Reiferon Retard

Chronic hepatitis B

Adult patients

Reiferon Retard is indicated for the treatment of hepatitis B envelope antigen (HBeAg)-positive or HBeAg-negative chronic hepatitis B (CHB) in adult patients with compensated liver disease and evidence of viral replication, increased alanine aminotransferase (ALT) and histologically verified liver inflammation and/or fibrosis.

Paediatric patients 3 years of age and older

Reiferon Retard is indicated for the treatment of HBeAg-positive CHB in non-cirrhotic children and adolescents 3 years of age and older with evidence of viral replication and persistently elevated serum ALT levels.4 and 5.1.

Chronic hepatitis C

Adult patients

Reiferon Retard is indicated in combination with other medicinal products, for the treatment of chronic hepatitis C (CHC) in patients with compensated liver disease.

Paediatric patients 5 years of age and older

Reiferon Retard in combination with ribavirin is indicated for the treatment of CHC in treatment-naïve children and adolescents 5 years of age and older who are positive for serum HCV-RNA.

When deciding to initiate treatment in childhood, it is important to consider growth inhibition induced by combination therapy. The reversibility of growth inhibition is uncertain. The decision to treat should be made on a case by case basis.

Treatment should be initiated only by a physician experienced in the treatment of patients with hepatitis B or C.

Refer also to the Summary of Product Characteristics of the medicinal products that are used in combination with Reiferon Retard.

Monotherapy for hepatitis C should only be considered in case of contraindication to other medicinal products.

Posology

Chronic hepatitis B - adult patients

The recommended dosage and duration of Reiferon Retard for both HBeAg-positive and HBeAg-negative CHB is 180 micrograms once weekly for 48 weeks.

Chronic hepatitis C

Treatment-naïve adult patients

The recommended dose for Reiferon Retard is 180 micrograms once weekly given in combination with oral ribavirin or as monotherapy.

The dose of ribavirin to be used in combination with Reiferon Retard is given in Table 1.

The ribavirin dose should be administered with food.

Duration of treatment - dual therapy with Reiferon Retard and ribavirin

The duration of combination therapy with ribavirin for CHC depends on viral genotype. Patients infected with HCV genotype 1 who have detectable HCV RNA at week 4 regardless of pre-treatment viral load should receive 48 weeks of therapy.

Treatment for 24 weeks may be considered in patients infected with

- genotype 1 with low viral load (LVL) (≤ 800,000 IU/ml) at baseline or

- genotype 4

who become HCV RNA negative at week 4 and remain HCV RNA negative at week 24. However, an overall 24 weeks treatment duration may be associated with a higher risk of relapse than a 48 weeks treatment duration. In these patients, tolerability to combination therapy and additional prognostic factors such as degree of fibrosis should be taken into account when deciding on treatment duration. Shortening the treatment duration in patients with genotype 1 and high viral load (HVL) (>800, 000 IU/ml) at baseline who become HCV RNA negative at week 4 and remain HCV RNA negative at week 24 should be considered with even more caution since the limited data available suggest that this may significantly negatively impact the sustained virologic response.

Patients infected with HCV genotype 2 or 3 who have detectable HCV RNA at week 4, regardless of pre-treatment viral load should receive 24 weeks of therapy. Treatment for only 16 weeks may be considered in selected patients infected with genotype 2 or 3 with LVL (≤ 800,000 IU/ml) at baseline who become HCV negative by week 4 of treatment and remains HCV negative by week 16. Overall 16 weeks of treatment may be associated with a lower chance of response and is associated with a higher risk of relapse than a 24-week treatment duration. In these patients, tolerability to combination therapy and the presence of additional clinical or prognostic factors such as degree of fibrosis should be taken into account when considering deviations from standard 24 weeks treatment duration. Shortening the treatment duration in patients infected with genotype 2 or 3 with HVL (> 800,000 IU/ml) at baseline who become HCV negative by week 4 should be considered with more caution as this may significantly negatively impact the sustained virological response (see Table 1).

Available data for patients infected with genotype 5 or 6 are limited; therefore combination treatment with 1,000/1,200 mg of ribavirin for 48 weeks is recommended.

Table 1: Dosing recommendations for combination therapy for adult patients with chronic hepatitis C

*RVR = rapid viral response (HCV RNA undetectable) at week 4 and HCV RNA undetectable at week 24;

**RVR = rapid viral response (HCV RNA negative) by week 4

LVL = ≤ 800,000 IU/ml; HVL = > 800,000 IU/ml

^(a) It is presently not clear whether a higher dose of ribavirin (e.g.1000/1200 mg/day based on body weight) results in higher SVR rates than does the 800 mg/day, when treatment is shortened to 16 weeks.

The ultimate clinical impact of a shortened initial treatment of 16 weeks instead of 24 weeks is unknown, taking into account the need for re-treating non-responding and relapsing patients.

The recommended duration of Reiferon Retard monotherapy is 48 weeks.

Treatment-experienced adult patients

The recommended dose of Reiferon Retard in combination with ribavirin is 180 mcg once weekly by subcutaneous administration. For patients <75 kg and >75 kg, 1000 mg daily and 1200 mg daily of ribavirin, respectively, and regardless of genotype, should be administered.

Patients who have detectable virus at week 12 should stop therapy. The recommended total duration of therapy is 48 weeks. If patients infected with virus genotype 1, not responding to prior treatment with peginterferon and ribavirin are considered for treatment, the recommended total duration of therapy is 72 weeks.

HIV-HCV co-infected adult patients

The recommended dosage for Reiferon Retard, alone or in combination with ribavirin, is 180 micrograms once weekly subcutaneously for 48 weeks. For patients infected with HCV genotype 1 <75 kg and >75 kg, 1000 mg daily and 1200 mg daily of ribavirin, respectively, should be administered. Patients infected with HCV genotypes other than genotype 1 should receive 800 mg daily of ribavirin. A duration of therapy less than 48 weeks has not been adequately studied.

Duration of therapy when Reiferon Retard is used in combination with other medicinal products

Refer also to the Summary of Product Characteristics of the medicinal products that are used in combination with Reiferon Retard.

Predictability of response and non-response with Reiferon Retard and ribavirin dual therapy - treatment-naïve patients

Early virological response by week 12, defined as a 2 log viral load decrease or undetectable levels of HCV RNA has been shown to be predictive for sustained response (see Tables 2 and 13).

Table 2: Predictive value of week 12 virological response at the recommended dosing regimen while on Reiferon Retard combination therapy in adult patients with chronic hepatitis C

The negative predictive value for sustained response in patients treated with Reiferon Retard in monotherapy was 98%.

A similar negative predictive value has been observed in HIV-HCV co-infected patients treated with Reiferon Retard monotherapy or in combination with ribavirin (100% (130/130) or 98% (83/85), respectively). Positive predictive values of 45% (50/110) and 70% (59/84) were observed for genotype 1 and genotype 2/3 HIV-HCV co-infected patients receiving combination therapy.

Predictability of response and non-response with Reiferon Retard and ribavirin dual therapy - treatment-experienced patients

In non-responder patients re-treated for 48 or 72 weeks, viral suppression at week 12 (undetectable HCV RNA defined as <50 IU/ml) has been shown to be predictive for sustained virological response. The probabilities of not achieving a sustained virological response with 48 or 72 weeks of treatment if viral suppression was not achieved at week 12 were 96% (363 of 380) and 96% (324 of 339), respectively. The probabilities of achieving a sustained virological response with 48 or 72 weeks of treatment if viral suppression was achieved at week 12 were 35% (20 of 57) and 57% (57 of 100), respectively.

Dose adjustment for adverse reactions in adult patients

General

Where dose adjustment is required for moderate to severe adverse reactions (clinical and/or laboratory) initial dose reduction to 135 micrograms is generally adequate for adult patients. In some cases, dose reduction to 90 micrograms or 45 micrograms is necessary. Dose increases to or towards the original dose may be considered when the adverse reaction abates.

Haematological (see also Table 3)

For adults, dose reduction is recommended if the absolute neutrophil count (ANC) is 500 to < 750 cells/mm³. For patients with ANC < 500 cells/mm³ treatment should be suspended until ANC values return to > 1000 cells/mm³. Therapy should initially be re-instituted at 90 micrograms Reiferon Retard and the neutrophil count monitored.

Dose reduction to 90 micrograms is recommended if the platelet count is 25,000 to < 50,000 cells/mm³. Treatment discontinuation is recommended when platelet count decreases to levels < 25,000 cells/mm³.

Specific recommendations for management of treatment-emergent anaemia in adults are as follows: ribavirin should be reduced to 600 milligrams/day (200 milligrams in the morning and 400 milligrams in the evening) if either of the following apply: (1) a patient without significant cardiovascular disease experiences a fall in haemoglobin to < 10 g/dl and > 8.5 g/dl, or (2) a patient with stable cardiovascular disease experiences a fall in haemoglobin by > 2 g/dl during any 4 weeks of treatment. A return to original dosing is not recommended. Ribavirin should be discontinued if either of the following applies: (1) a patient without significant cardiovascular disease experiences a fall in haemoglobin confirmed to < 8.5 g/dl; (2) a patient with stable cardiovascular disease maintains a haemoglobin value < 12 g/dl despite 4 weeks on a reduced dose. If the abnormality is reversed, ribavirin may be restarted at 600 milligrams daily, and further increased to 800 milligrams daily at the discretion of the treating physician. A return to original dosing is not recommended.

In case of intolerance to ribavirin, Reiferon Retard monotherapy should be continued.

Liver function

Fluctuations in abnormalities of liver function tests are common in patients with CHC. Increases in ALT levels above baseline (BL) have been observed in patients treated with Reiferon Retard, including patients with a virological response.

In CHC clinical trials with adult patients, isolated increases in ALT (> 10x upper limit of normal [ULN], or > 2x BL for patients with a BL ALT > 10x ULN) which resolved without dose-modification were observed in 8 of 451 patients treated with combination therapy. If ALT increase is progressive or persistent, the dose should be reduced initially to 135 micrograms. When increases in ALT levels are progressive despite dose reduction, or are accompanied by increased bilirubin or evidence of hepatic decompensation, therapy should be discontinued.

For CHB patients, transient flares of ALT levels sometimes exceeding 10x ULN are not uncommon, and may reflect immune clearance. Treatment should normally not be initiated if ALT is >10x ULN. Consideration should be given to continuing treatment with more frequent monitoring of liver function during ALT flares. If the Reiferon Retard dose is reduced or withheld, therapy can be restored once the flare is subsiding.

Special populations

Elderly

Adjustments in the recommended dosage of 180 micrograms once weekly are not necessary when instituting Reiferon Retard therapy in elderly patients.

Renal impairment

No dose adjustment is required for adult patients with mild or moderate renal impairment. A reduced dose of 135 mcg once weekly is recommended in adult patients with severe renal impairment or end stage renal disease. Regardless of the starting dose or degree of renal impairment, patients should be monitored and appropriate dose reductions of Reiferon Retard during the course of therapy should be made in the event of adverse reactions.

Hepatic impairment

In patients with compensated cirrhosis (e.g., Child-Pugh A), Reiferon Retard has been shown to be effective and safe. Reiferon Retard has not been evaluated in patients with decompensated cirrhosis (e.g., Child-Pugh B or C or bleeding oesophageal varices).

The Child-Pugh classification divides patients into groups A, B, and C, or "Mild", "Moderate" and "Severe" corresponding to scores of 5-6, 7-9 and 10-15, respectively.

Modified Assessment

*Grading according to Trey, Burns and Saunders (1966)

Paediatric population

Reiferon Retard is contraindicated in neonates and young children up to 3 years old due to the excipient benzyl alcohol.

It is recommended that Reiferon Retard pre-filled syringes be used for paediatric patients. The Reiferon Retard pre-filled pens do not allow for appropriate adjustment of dosing in these patients. Patients who initiate treatment prior to their 18^th birthday should maintain paediatric dosing through the completion of therapy.

The posology of Reiferon Retard in paediatric patients is based on the Body Surface Area (BSA). To calculate BSA, it is recommended to use Mosteller's equation:

The recommended duration of therapy is 48 weeks in patients with CHB.

Before initiating therapy for CHB, persistently elevated serum ALT levels should have been documented. The response rate was lower in patients with no to minimal increase in ALT level at baseline.

The duration of treatment with Reiferon Retard in combination with ribavirin in paediatric patients with CHC depends on viral genotype. Patients infected with viral genotypes 2 or 3 should receive 24 weeks of treatment, while patients infected with any other genotype should receive 48 weeks of therapy. Patients who still have detectable levels of HCV-RNA despite an initial 24 weeks of therapy, should discontinue therapy, as it is unlikely they will be able to achieve a sustained virological response with continued therapy.

For children and adolescents aged 3 to 17 years with CHB and having a BSA greater than 0.54 m² and for children and adolescents aged 5 to 17 years with CHC and having a BSA greater than 0.71 m², the recommended doses for Reiferon Retard are provided in Table 4.

Table 4: Reiferon Retard dosing recommendations for paediatric patients with chronic hepatitis B and chronic hepatitis C

For paediatric patients, based on toxicities, up to three levels of dose modification can be made before dose interruption or discontinuation is considered (see Table 5).

Table 5: Reiferon Retard dose modification recommendations in paediatric patients with chronic hepatitis B or chronic hepatitis C

Recommendations for dose modifications of Reiferon Retard for toxicities in the CHB and CHC paediatric populations are presented in Table 6.

Table 6: Reiferon Retard dose modification recommendations for toxicities in paediatric patients with chronic hepatitis B or chronic hepatitis C

Dose adjustement in paediatric patients - dual therapy with Reiferon Retard and ribavirin

For children and adolescents aged 5 to 17 years with CHC, the recommended dose of ribavirin is based on the patient's body weight, with a target dose of 15 mg/kg/day, divided in two daily doses. For children and adolescents 23 kg or greater, a dosing schedule using 200 mg ribavirin tablets is provided in Table 7. Patients and caregivers must not attempt to break the 200 mg tablets.

Table 7: Ribavirin dosing recommendations for paediatric patients with chronic hepatitis C aged 5 to 17 years

It is important to note that ribavirin should never be given as monotherapy. Unless otherwise noted, the management of all other toxicities should follow the adult recommendations.

In paediatric patients, ribavirin treatment-associated toxicities, such as treatment-emergent anaemia, will be managed by reduction of the full dose. The dose reduction levels are provided in Table 8.

Table 8: Ribavirin dose modification recommendations in paediatric patients with chronic hepatitis C

There is limited experience with Reiferon Retard in treating paediatric patients with CHC aged 3 to 5 years, or who have failed to be adequately treated previously. There are no data in paediatric patients coinfected with HCV/HIV or with renal impairment.

Method of administration

Reiferon Retard is administered subcutaneously in the abdomen or thigh. Exposure to Reiferon Retard was decreased in studies following administration of Reiferon Retard in the arm.

Reiferon Retard is designed for administration by the patient or carer. Each syringe should be used by one person only and is for single use.

Appropriate training is recommended for non-healthcare professionals administering this medicinal product. The “Instructions for the User”, provided in the carton, must be followed carefully by the patient.

-

- Autoimmune hepatitis

- Severe hepatic dysfunction or decompensated cirrhosis of the liver

- A history of severe pre-existing cardiac disease, including unstable or uncontrolled cardiac disease in the previous six months

- HIV-HCV patients with cirrhosis and a Child-Pugh score > 6, except if only due to indirect hyperbilirubinemia caused by medicinal products such as atazanavir and indinavir

- Combination with telbivudine

- )

- In paediatric patients, the presence of, or history of severe psychiatric condition, particularly severe depression, suicidal ideation or suicidal attempt

In order to improve the traceability of biological medicinal products, the trade name and the batch number of the administered product should be clearly recorded (or stated) in the patient file.

Laboratory tests prior to and during therapy

Prior to beginning Reiferon Retard therapy, standard haematological and biochemical laboratory tests are recommended for all patients.

The following may be considered as baseline values for initiation of treatment:

- Platelet count > 90,000 cells/mm³

- ANC > 1500 cells/mm³

- Adequately controlled thyroid function (TSH and T4)

Haematological tests should be repeated after 2 and 4 weeks and biochemical tests should be performed at 4 weeks. Additional testing should be performed periodically during therapy (including glucose monitoring).

In clinical trials, Reiferon Retard treatment was associated with decreases in both total white blood cell (WBC) count and ANC, usually starting within the first 2 weeks of treatment. Progressive decreases after 8 weeks of therapy were infrequent. The decrease in ANC was reversible upon dose reduction or cessation of therapy , reached normal values by 8 weeks in the majority of patients and returned to baseline in all patients after about 16 weeks.

Reiferon Retard treatment has been associated with decreases in platelet count, which returned to pre-treatment levels during the post-treatment observation period. In some cases, dose modification may be necessary.

The occurrence of anaemia (haemoglobin <10 g/dl) has been observed in up to 15% of CHC patients in clinical trials on the combined treatment of Reiferon Retard with ribavirin. The frequency depends on the treatment duration and the dose of ribavirin. The risk of developing anaemia is higher in the female population.

Caution should be exercised when administering Reiferon Retard in combination with other potentially myelosuppressive agents.

Pancytopenia and bone marrow suppression have been reported in the literature to occur within 3 to 7 weeks after the administration of a peginterferon and ribavirin concomitantly with azathioprine. This myelotoxicity was reversible within 4 to 6 weeks upon withdrawal of HCV antiviral therapy and concomitant azathioprine and did not recur upon re-introduction of either treatment alone.

The use of Reiferon Retard and ribavirin combination therapy in CHC patients who failed prior treatment has not been adequately studied in patients who discontinued prior therapy for haematological adverse reactions. Physicians considering treatment in these patients should carefully weigh the risks versus the benefits of re-treatment.

Endocrine system

Thyroid function abnormalities or worsening of pre-existing thyroid disorders have been reported with the use of alfa interferons, including Reiferon Retard. Prior to initiation of Reiferon Retard therapy, TSH and T4 levels should be evaluated. Reiferon Retard treatment may be initiated or continued if TSH levels can be maintained in the normal range by pharmaceutical means. TSH levels should be determined during the course of therapy if a patient develops clinical symptoms consistent with possible thyroid dysfunction. Hypoglycaemia, hyperglycaemia and diabetes mellitus have been observed with Reiferon Retard. Patients with these conditions who cannot be effectively controlled by medication should not begin Reiferon Retard monotherapy or Reiferon Retard/ribavirin combination therapy. Patients who develop these conditions during treatment and cannot be controlled with medication should discontinue Reiferon Retard or Reiferon Retard/ribavirin therapy.

Cardiovascular system

Hypertension, supraventricular arrhythmias, congestive heart failure, chest pain and myocardial infarction have been associated with alfa interferon therapies, including Reiferon Retard. It is recommended that patients who have pre-existing cardiac abnormalities have an electrocardiogram prior to initiation of Reiferon Retard therapy. If there is any deterioration of cardiovascular status, therapy should be suspended or discontinued. In patients with cardiovascular disease, anaemia may necessitate dose reduction or discontinuation of ribavirin.

Liver function

In patients who develop evidence of hepatic decompensation during treatment, Reiferon Retard should be discontinued. Increases in ALT levels above baseline have been observed in patients treated with Reiferon Retard, including patients with a viral response. When the increase in ALT levels is progressive and clinically significant, despite dose reduction, or is accompanied by increased direct bilirubin, therapy should be discontinued.

In CHB, unlike CHC, disease exacerbations during therapy are not uncommon and are characterised by transient and potentially significant increases in serum ALT. In clinical trials with Reiferon Retard in HBV, marked transaminase flares have been accompanied by mild changes in other measures of hepatic function and without evidence of hepatic decompensation. In approximately half the cases of flares exceeding 10x ULN, Reiferon Retard dosing was reduced or withheld until the transaminase elevations subsided, while in the rest therapy was continued unchanged. More frequent monitoring of hepatic function was recommended in all instances.

Hypersensitivity

Serious, acute hypersensitivity reactions (e.g., urticaria, angioedema, bronchoconstriction, anaphylaxis) have been rarely observed during alfa interferon therapy. If this occurs, therapy must be discontinued and appropriate medical therapy instituted immediately. Transient rashes do not necessitate interruption of treatment.

Autoimmune disease

The development of auto-antibodies and autoimmune disorders has been reported during treatment with alfa interferons.8).

Cases of Vogt-Koyanagi-Harada (VKH) syndrome have been reported in patients with CHC treated with interferon. This syndrome is a granulomatous inflammatory disorder affecting the eyes, auditory system, meninges, and skin. If VKH syndrome is suspected, antiviral treatment should be withdrawn and corticosteroid therapy discussed.

Fever/infections

While fever may be associated with the flu-like syndrome reported commonly during interferon therapy, other causes of persistent fever, particularly serious infections (bacterial, viral, fungal) must be ruled out, especially in patients with neutropenia. Serious infections (bacterial, viral, fungal) and sepsis have been reported during treatment with alfa interferons including Reiferon Retard. Appropriate anti-infective therapy should be started immediately and discontinuation of therapy should be considered.

Ocular changes

Retinopathy including retinal haemorrhages, cotton wool spots, papilloedema, optic neuropathy and retinal artery or vein obstruction which may result in loss of vision have been reported in rare instances with Reiferon Retard. All patients should have a baseline eye examination. Any patient complaining of decrease or loss of vision must have a prompt and complete eye examination. Adult and paediatric patients with preexisting ophthalmologic disorders (e.g., diabetic or hypertensive retinopathy) should receive periodic ophthalmologic exams during Reiferon Retard therapy. Reiferon Retard treatment should be discontinued in patients who develop new or worsening ophthalmologic disorders.

Pulmonary changes

Pulmonary symptoms, including dyspnoea, pulmonary infiltrates, pneumonia, and pneumonitis have been reported during therapy with Reiferon Retard. In case of persistent or unexplained pulmonary infiltrates or pulmonary function impairment, treatment should be discontinued.

Skin disorder

Use of alfa interferons has been associated with exacerbation or provocation of psoriasis and sarcoidosis. Reiferon Retard must be used with caution in patients with psoriasis, and in cases of onset or worsening of psoriatic lesions, discontinuation of therapy should be considered.

Transplantation

The safety and efficacy of Reiferon Retard and ribavirin treatment have not been established in patients with liver and other transplantations. Liver and renal graft rejections have been reported with Reiferon Retard, alone or in combination with ribavirin.

HIV-HCV co-infection

Please refer to the respective Summary of Product Characteristics of the antiretroviral medicinal products that are to be taken concurrently with HCV therapy for awareness and management of toxicities specific for each product and the potential for overlapping toxicities with Reiferon Retard with or without ribavirin. In study NR15961, patients concurrently treated with stavudine and interferon therapy with or without ribavirin, the incidence of pancreatitis and/or lactic acidosis was 3% (12/398).

Patients co-infected with HIV and receiving Highly Active Anti-Retroviral Therapy (HAART) may be at increased risk of developing lactic acidosis. Caution should therefore be exercised when adding Reiferon Retard and ribavirin to HAART therapy (see ribavirin SmPC).

Co-infected patients with advanced cirrhosis receiving HAART may also be at increased risk of hepatic decompensation and possibly death if treated with ribavirin in combination with interferons, including Reiferon Retard. Baseline variables in co-infected cirrhotic patients that may be associated with hepatic decompensation include: increased serum bilirubin, decreased haemoglobin, increased alkaline phosphatase or decreased platelet count, and treatment with didanosine (ddI).

The concomitant use of ribavirin with zidovudine is not recommended due to an increased risk of anaemia.

During treatment, co-infected patients should be closely monitored for signs and symptoms of hepatic decompensation (including ascites, encephalopathy, variceal bleeding, impaired hepatic synthetic function; e.g., Child-Pugh score of 7 or greater). The Child-Pugh scoring may be affected by factors related to treatment (i.e. indirect hyperbilirubinemia, decreased albumin) and not necessarily attributable to hepatic decompensation. Treatment with Reiferon Retard should be discontinued immediately in patients with hepatic decompensation.

In patients co-infected with HIV-HCV, limited efficacy and safety data are available in patients with CD4 counts less than 200 cells/µl. Caution is therefore warranted in the treatment of patients with low CD4 counts.

Dental and periodontal disorders

Dental and periodontal disorders, which may lead to loss of teeth, have been reported in patients receiving Reiferon Retard and ribavirin combination therapy. In addition, dry mouth could have a damaging effect on teeth and mucous membranes of the mouth during long-term treatment with the combination of Reiferon Retard and ribavirin. Patients should brush their teeth thoroughly twice daily and have regular dental examinations. In addition some patients may experience vomiting. If this reaction occurs, they should be advised to rinse out their mouth thoroughly afterwards.

Use of peginterferon as long term maintenance monotherapy (unapproved use)

In a randomised, controlled US study (HALT-C) of HCV non-responder patients with varied degrees of fibrosis where 3.5 years of treatment with 90 micrograms/week of Reiferon Retard monotherapy was studied, no significant reductions were observed in the rate of fibrosis progression or related clinical events.

Excipient

Reiferon Retard contains benzyl alcohol. Must not be given to premature babies or neonates. May cause toxic reactions and anaphylactoid reactions in infants and children up to 3 years old.

Reiferon Retard has minor or moderate influence on the ability to drive and use machines. Patients who develop dizziness, confusion, somnolence or fatigue should be cautioned to avoid driving or operating machinery.

Summary of the safety profile

Chronic hepatitis B in adult patients

In clinical trials of 48 weeks treatment and 24 weeks follow-up, the safety profile for Reiferon Retard in CHB was similar to that seen in CHC. With the exception of pyrexia the frequency of the majority of the reported adverse reactions was notably less in CHB patients treated with Reiferon Retard monotherapy compared with CHC patients treated with Reiferon Retard monotherapy (see Table 9). Adverse events were experienced by 88% of Reiferon Retard-treated patients as compared with 53% of patients in the lamivudine comparator group, while 6% of the Reiferon Retard-treated and 4% of the lamivudine-treated patients experienced serious adverse events during the studies. Adverse events or laboratory abnormalities led to 5% of patients withdrawing from Reiferon Retard treatment, while less than 1% of patients withdrew from lamivudine treatment for these reasons. The percentage of patients with cirrhosis who withdrew from treatment was similar to that of the overall population in each treatment group.

Chronic hepatitis C in adult patients

The frequency and severity of the most commonly reported adverse reactions with Reiferon Retard are similar to those reported with interferon alfa-2a (see Table 9). The most frequently reported adverse reactions with Reiferon Retard 180 micrograms were mostly mild to moderate in severity and were manageable without the need for modification of doses or discontinuation of therapy.

Chronic hepatitis C in prior non-responder patients

Overall, the safety profile for Reiferon Retard in combination with ribavirin in prior non-responder patients was similar to that in naïve patients. In a clinical trial of non-responder patients to prior pegylated interferon alfa-2b/ribavirin, which exposed patients to either 48 or 72 weeks of treatment, the frequency of withdrawal for adverse events or laboratory abnormalities from Reiferon Retard treatment and ribavirin treatment was 6% and 7%, respectively, in the 48 week arms and 12% and 13%, respectively, in the 72 week arms. Similarly for patients with cirrhosis or transition to cirrhosis, the frequencies of withdrawal from Reiferon Retard treatment and ribavirin treatment were higher in the 72-week treatment arms (13% and 15%) than in the 48-week arms (6% and 6%). Patients who withdrew from previous therapy with pegylated interferon alfa-2b/ribavirin because of haematological toxicity were excluded from enrolling in this trial.

In another clinical trial, non-responder patients with advanced fibrosis or cirrhosis (Ishak score of 3 to 6) and baseline platelet counts as low as 50,000 cells/mm³ were treated for 48 weeks. Haematologic laboratory abnormalities observed during the first 20 weeks of the trial included anaemia (26% of patients experienced a haemoglobin level of <10 g/dl), neutropenia (30% experienced an ANC <750 cells/mm³), and thrombocytopenia (13% experienced a platelet count <50,000 cells/mm³).

Chronic hepatitis C and HIV co-infection

In HIV-HCV co-infected patients, the clinical adverse reaction profiles reported for Reiferon Retard, alone or in combination with ribavirin, were similar to those observed in HCV mono-infected patients. For HIV-HCV patients receiving Reiferon Retard and ribavirin combination therapy other undesirable effects have been reported in > 1% to ≤ 2% of patients: hyperlactacidaemia/lactic acidosis, influenza, pneumonia, affect lability, apathy, tinnitus, pharyngolaryngeal pain, cheilitis, acquired lipodystrophy and chromaturia. Reiferon Retard treatment was associated with decreases in absolute CD4+ cell counts within the first 4 weeks without a reduction in CD4+ cell percentage. The decrease in CD4+ cell counts was reversible upon dose reduction or cessation of therapy. The use of Reiferon Retard had no observable negative impact on the control of HIV viraemia during therapy or follow-up. Limited safety data are available in co-infected patients with CD4+ cell counts <200/µl.

Tabulated list of adverse reactions

Table 9 summarises the undesirable effects reported with Reiferon Retard monotherapy in CHB or CHC adult patients and with Reiferon Retard in combination with ribavirin in CHC patients. Undesirable effects reported in clinical studies are grouped according to frequency as follows: very common (> 1/10), common (> 1/100 to < 1/10), uncommon (> 1/1000 to < 1/100), rare (> 1/10,000 to < 1/1000), very rare (< 1/10,000). For spontaneous reports of undesirable effects from post-marketing experience, the frequency is not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in decreasing order of seriousness.

Table 9: Undesirable effects reported with Reiferon Retard monotherapy for CHB or CHC or in combination with ribavirin for CHC patients in clinical trials and post marketing

*These adverse reactions were common (>1/100 to < 1/10) in CHB patients treated with Reiferon Retard monotherapy

^§ Class label for interferon products, see below Pulmonary arterial hypertension.

Description of selected adverse reactions

Pulmonary arterial hypertension

Cases of pulmonary arterial hypertension (PAH) have been reported with interferon alfa products, notably in patients with risk factors for PAH (such as portal hypertension, HIV infection, cirrhosis). Events were reported at various time points typically several months after starting treatment with interferon alfa.

Laboratory values

Reiferon Retard treatment was associated with abnormal laboratory values: ALT increase, bilirubin increase, electrolyte disturbance (hypokalaemia, hypocalcaemia, hypophosphataemia), hyperglycaemia, hypoglycaemia and elevated triglycerides. With both Reiferon Retard monotherapy, and also the combined treatment with ribavirin, up to 2% of patients experienced increased ALT levels that led to dose modification or discontinuation of the treatment.

Treatment with Reiferon Retard was associated with decreases in haematological values (leucopenia, neutropenia, lymphopenia, thrombocytopenia and haemoglobin), which generally improved with dose modification, and returned to pre-treatment levels within 4-8 weeks upon cessation of therapy.

Moderate (ANC: 0.749 - 0.5 x 10⁹/l) and severe (ANC: < 0.5 x 10⁹/l) neutropenia was observed respectively in 24% (216/887) and 5% (41/887) of patients receiving Reiferon Retard 180 micrograms and ribavirin 1000/1200 milligrams for 48 weeks.

Anti-interferon antibodies

1-5% of patients treated with Reiferon Retard developed neutralising anti-interferon antibodies. As with other interferons, a higher incidence of neutralising antibodies was seen in CHB. However in neither disease was this correlated with lack of therapeutic response.

Thyroid function

Reiferon Retard treatment was associated with clinically significant abnormalities in thyroid laboratory values requiring clinical intervention. The frequencies observed (4.9%) in patients receiving Reiferon Retard/ribavirin (NV15801) are similar to those observed with other interferons.

Laboratory values for HIV-HCV co-infected patients

Although haematological toxicities of neutropenia, thrombocytopenia and anaemia occurred more frequently in HIV-HCV patients, the majority could be managed by dose modification and the use of growth factors and infrequently required premature discontinuation of treatment. Decrease in ANC levels below 500 cells/mm³ was observed in 13% and 11% of patients receiving Reiferon Retard monotherapy and combination therapy, respectively. Decrease in platelets below 50,000 cells/mm³ was observed in 10% and 8% of patients receiving Reiferon Retard monotherapy and combination therapy, respectively. Anaemia (haemoglobin < 10 g/dl) was reported in 7% and 14% of patients treated with Reiferon Retard monotherapy or in combination therapy, respectively.

Paediatric population

Chronic hepatitis B

In a clinical trial (YV25718) with 111 paediatric patients (3 to 17 years of age) treated with Reiferon Retard for 48 weeks, the safety profile was consistent with that seen in adults with CHB and in paediatric patients with CHC.

The mean changes from baseline in height and weight for age Z-scores at Week 48 of treatment in study YV25718 were -0.07 and -0.21(n=108 and n= 106 respectively) for Reiferon Retard-treated patients as compared to - 0.01 and -0.08 (n=47 each) in untreated patients. At Week 48 of Reiferon Retard treatment, a height or weight percentile decrease of more than 15 percentiles on the normative growth curves was observed in 6% of patients for height and 11% of patient for weight, whereas in the untreated group it was 2% of patients for height and 9% for weight. No data is available on long-term follow-up post-treatment in these patients.

Chronic hepatitis C

In a clinical trial with 114 paediatric patients (5 to 17 years of age) treated with Reiferon Retard alone or in combination with ribavirin , dose modifications were required in approximately one-third of patients, most commonly for neutropenia and anaemia. In general, the safety profile observed in paediatric patients was similar to that seen in adults. In the paediatric study, the most prevalent adverse reactions in patients treated with combination therapy for up to 48 weeks with Reiferon Retard and ribavirin were influenza-like illness (91%), headache (64%), gastrointestinal disorder (56%), and injection-site reaction (45%). A full listing of adverse reactions reported in this treatment group (n=55) is provided in Table 10. Seven patients receiving combination Reiferon Retard and ribavirin treatment for 48 weeks discontinued therapy for safety reasons (depression, psychiatric evaluation abnormal, transient blindness, retinal exudates, hyperglycaemia, type 1 diabetes mellitus, and anaemia). Most of the adverse reactions reported in the study were mild or moderate in severity. Severe adverse reactions were reported in 2 patients in the Reiferon Retard plus ribavirin combination therapy group (hyperglycaemia and cholecystectomy).

Growth inhibition was observed in paediatric patients. Paediatric patients treated with Reiferon Retard plus ribavirin combination therapy showed a delay in weight and height increases after 48 weeks of therapy compared with baseline. Patient 'weight for age' and 'height for age' percentiles of the normative population decreased during treatment. At the end of 2 years follow-up after treatment, most patients had returned to baseline normative growth curve percentiles for weight and height (mean weight percentile was 64% at baseline and 60% at 2 years post-treatment; mean height percentile was 54% at baseline and 56% at 2 years post-treatment). At the end of treatment, 43% of patients experienced a weight percentile decrease of 15 percentiles or more, and 25% (13 of 53) experienced a height percentile decrease of 15 percentiles or more on the normative growth curves. At 2 years post-treatment, 16% (6 of 38) of patients remained 15 percentiles or more below their baseline weight curve and 11% (4 of 38) remained 15 percentiles or more below their baseline height curve.

55% (21 of 38) of subjects who completed the original study enrolled in the long-term follow up extending up to 6 years post-treatment. The study demonstrated that the post-treatment recovery in growth at 2 years post-treatment was maintained to 6 years post-treatment. For a few subjects who were more than 15 percentiles below their baseline height curve at 2 years post-treatment, they either returned to baseline comparable height percentiles at 6 years post-treatment or a non-treatment related causative factor has been identified. The extent of available data is not sufficient to conclude that growth inhibition due to Reiferon Retard exposure is always reversible.

Table 10: Adverse reactions reported among paediatric patients infected with HCV and assigned to Reiferon Retard plus ribavirin in study NV17424

Laboratory values

Decreases in haemoglobin, neutrophils, platelets or increased ALT may require dose reduction or permanent discontinuation from treatment. Most laboratory abnormalities noted during the clinical trial returned to baseline levels shortly after discontinuation of treatment.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions (see details below).

Ireland

HPRA Pharmacovigilance

Earlsfort Terrace

IRL - Dublin 2

Tel: +353 1 6764971

Fax: +353 1 6762517

Website: www.hpra.ie

e-mail: [email protected]

Malta

ADR Reporting

Website: www.medicinesauthority.gov.mt/adrportal

United Kingdom

Yellow Card Scheme

Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store

Overdoses involving between two injections on consecutive days (instead of weekly interval) up to daily injections for 1 week (i.e., 1260 micrograms/week) have been reported. None of these patients experienced unusual, serious or treatment-limiting events. Weekly doses of up to 540 and 630 micrograms have been administered in renal cell carcinoma and chronic myelogenous leukaemia clinical trials, respectively. Dose limiting toxicities were fatigue, elevated liver enzymes, neutropenia and thrombocytopenia, consistent with interferon therapy.

Pharmacotherapeutic group: Immunostimulants, interferons, ATC code: L03AB11

Mechanism of action

The conjugation of PEG reagent (bis-monomethoxypolyethylene glycol) to interferon alfa-2a forms a pegylated interferon alfa-2a (Reiferon Retard). Reiferon Retard possesses the in vitro antiviral and antiproliferative activities that are characteristic of interferon alfa-2a.

Interferon alfa-2a is conjugated with bis-[monomethoxy polyethylene glycol] at a degree of substitution of one mole of polymer/mole of protein. The average molecular mass is approximately 60,000 of which the protein moiety constitutes approximately 20,000.

Pharmacodynamic effects

HCV RNA levels decline in a biphasic manner in responding patients with hepatitis C who have received treatment with 180 micrograms Reiferon Retard. The first phase of decline occurs 24 to 36 hours after the first dose of Reiferon Retard and is followed by the second phase of decline which continues over the next 4 to 16 weeks in patients who achieve a sustained response. Ribavirin had no significant effect on the initial viral kinetics over the first 4 to 6 weeks in patients treated with the combination of ribavirin and pegylated interferon alfa-2a or interferon alfa.

Clinical efficacy and safety

Chronic hepatitis B

Predictability of response

A patient-level meta-analysis of 9 Reiferon Retard clinical studies (n=1,423) in CHB HBeAg positive and HBeAg-negative patients demonstrated that HBsAg and HBV DNA levels at Week 12 of treatment, are predictive of final treatment outcome at Week 24 post-treatment in certain genotypes. Operating characteristics of these biomarkers are presented in Table 11. No single biomarker with a cut-off can be identified to optimize all the operating characteristics (negative predictive value [NPV], sensitivity, specificity) and practical characteristics (simplicity, convenience). Consideration for early treatment discontinuation should be evaluated in the context of a particular clinical situation.

For HBeAg-positive patients with HBV genotype B and C infection, HBsAg > 20,000 IU/mL or HBV DNA > 8 log₁₀ IU/mL at Week 12 following commencement of treatment is associated with high likelihood of failure to achieve HBeAg seroconversion and HBV-DNA <2,000 IU/mL at 24 week post-treatment (NPV > 90%). For HBV genotype A and D, subgroup size was insufficient to be analyzed.

For HBeAg-negative patients with HBV genotype D infection, HBsAg > 20,000 IU/mL or HBV DNA > 6.5 log₁₀ IU/mL at Week 12 following commencement of treatment is associated with high likelihood of failure to achieve HBV-DNA <2,000 IU/mL and ALT normalization at Week 24 post treatment. HBV genotype A subgroup size was insufficient to be analyzed. No biomarker can be identified with acceptable performance for HBeAg-negative patients with HBV genotype B or C infection.

Other published on-treatment biomarkers that are predictive of the final outcome of Reiferon Retard treatment may be considered.

Table 11: Performance of individual biomarkers at Week 12 of therapy in CHB HBeAg-positive and HBeAg-negative patients according to genotype

NPV= negative predictive value; Sensitivity = % of all responders not meeting the stopping rule; Specificity = % of all non-responders meeting stopping rule

(a) Treatment response for HBeAg-positive patients was defined as HBeAg seroconversion (defined as loss of HBeAg and presence of anti-HBe) + HBV DNA <2,000 IU/mL at 6 months post-treatment and treatment response for HBeAg-negative patients was defined as HBV DNA < 2,000 IU/mL + ALT normalization at 6 months post-treatment.

All clinical trials recruited patients with CHB who had active viral replication measured by HBV DNA, elevated levels of ALT and a liver biopsy consistent with chronic hepatitis. Study WV16240 recruited patients who were positive for HBeAg, while study WV16241 recruited patients who were negative for HBeAg and positive for anti-HBe. In both studies the treatment duration was 48 weeks, with 24 weeks of treatment-free follow-up. Both studies compared Reiferon Retard plus placebo vs Reiferon Retard plus lamivudine vs lamivudine alone. No HBV-HIV co-infected patients were included in these clinical trials.

Response rates at the end of follow-up for the two studies are presented in Table 12. In study WV16240, the primary efficacy endpoints were HBeAg seroconversion and HBV-DNA below 10⁵ copies/ml. In study WV16241, the primary efficacy endpoints were ALT normalisation and HBV-DNA below 2 x 10⁴ copies/ml. HBV-DNA was measured by the COBAS AMPLICORâ„¢ HBV MONITOR Assay (limit of detection 200 copies/ml).

A total of 283/1351 (21%) of patients had advanced fibrosis or cirrhosis, 85/1351 (6%) had cirrhosis. There was no difference in response rate between these patients and those without advanced fibrosis or cirrhosis.

Table 12: Serological, virological and biochemical responses in chronic hepatitis B

* For HBeAg-positive patients: HBV DNA < 10⁵ copies/ml

For HBeAg-negative/anti-HBe-positive patients: HBV DNA < 2 x 10⁴ copies/ml

# p-value (vs. lamivudine) < 0.01 (stratified Cochran-Mantel-Haenszel test)

Histological response was similar across the three treatment groups in each study; however, patients showing a sustained response 24 weeks after the end of treatment were significantly more likely to also show histological improvement.

All patients who completed the phase III studies were eligible for entry into a long-term follow-up study (WV16866). Among patients from study WV16240, who received Reiferon Retard monotherapy and entered the long-term follow-up study, the rate of sustained HBeAg seroconversion 12 months after the end of therapy was 48% (73/153). In patients receiving Reiferon Retard monotherapy in study WV16241, the rate of HBV DNA response and ALT normalisation 12 months after end of treatment were 42% (41/97) and 59% (58/99), respectively.

Chronic hepatitis C

Predictability of response

Dose-response in monotherapy

In a direct comparison with 90 micrograms, the 180 micrograms-dose was associated with superior sustained virological response in patients with cirrhosis, but in a study in non-cirrhotic patients very similar results were obtained with doses of 135 micrograms and 180 micrograms.

Confirmatory clinical trials in adult treatment-naïve patients

All clinical trials recruited interferon-naïve patients with CHC confirmed by detectable levels of serum HCV RNA, elevated levels of ALT (with the exception of study NR16071) and a liver biopsy consistent with chronic hepatitis. Study NV15495 specifically recruited patients with a histological diagnosis of cirrhosis (about 80%) or transition to cirrhosis (about 20%). Only HIV-HCV co-infected patients were included in the study NR15961 (see Table 21). These patients had stable HIV disease and mean CD4 T-cell count was about 500 cells/µl.

For HCV monoinfected patients and HIV-HCV co-infected patients, for treatment regimens, duration of therapy and study outcome see Tables 13, 14, 15 and Table 21, respectively. Virological response was defined as undetectable HCV RNA as measured by the COBAS AMPLICORâ„¢ HCV Test, version 2.0 (limit of detection 100 copies/ml equivalent to 50 International Units/ml) and sustained response as one negative sample approximately 6 months after end of therapy.

The virological responses of HCV monoinfected patients treated with Reiferon Retard and ribavirin combination therapy in relation to genotype and pre-treatment viral load and in relation to genotype, pre-treatment viral load and rapid virological response at week 4 are summarised in Table 14 and Table 15, respectively. The results of study NV15942 provide the rationale for recommending treatment regimens based on genotype, baseline viral load and virological response at week 4 (see Tables 1, 14 and 15).

The difference between treatment regimens was in general not influenced by presence/absence of cirrhosis; therefore treatment recommendations for genotype 1, 2 or 3 are independent of this baseline characteristic.

Table 14: Sustained virological response based on genotype and pre-treatment viral load after Reiferon Retard combination therapy with ribavirin in CHC patients

The possibility to consider shortening treatment duration to 24 weeks in genotype 1 and 4 patients was examined based on a sustained rapid virological response observed in patients with rapid virological response at week 4 in studies NV15942 and ML17131 (see Table 15).

Table 15: Sustained virological response based on rapid viral response at week 4 for genotype 1 and 4 after Reiferon Retard combination therapy with ribavirin in CHC patients

Low viral load = ≤ 800,000 IU/ml; High viral load = > 800,000 IU/ml

RVR = rapid viral response (HCV RNA undetectable) at week 4 and HCV RNA undetectable at week 24

Although limited, data indicated that shortening treatment to 24 weeks might be associated with a higher risk of relapse (see Table 16).

Table 16: Relapse of virological response at the end of treatment for rapid virological response population

The possibility of shortening treatment duration to 16 weeks in genotype 2 or 3 patients was examined based on a sustained virological response observed in patients with rapid virological response by week 4 in study NV17317 (see Table 17).

In study NV17317 in patients infected with viral genotype 2 or 3, all patients received Reiferon Retard 180 mcg sc qw and a ribavirin dose of 800 mg and were randomised to treatment for either 16 or 24 weeks. Overall treatment for 16 weeks resulted in lower sustained viral response (65%) than treatment for 24 weeks (76%) (p < 0.0001).

The sustained viral response achieved with 16 weeks of treatment and with 24 weeks of treatment was also examined in a retrospective subgroup analysis of patients who were HCV RNA negative by week 4 and had a LVL at baseline (see Table 17).

Table 17: Sustained virological response overall and based on rapid viral response by week 4 for genotype 2 or 3 after Reiferon Retard combination therapy with ribavirin in CHC patients

Low viral load = ≤ 800,000 IU/ml; High viral load = > 800,000 IU/ml

RVR = rapid viral response (HCV RNA undetectable) at week 4

It is presently not clear whether a higher dose of ribavirin (e.g.1000/1200 mg/day based on body weight) results in higher SVR rates than does the 800 mg/day, when treatment is shortened to 16 weeks.

The data indicated that shortening treatment to 16 weeks is associated with a higher risk of relapse (see Table 18).

Table 18: Relapse of virological response after the end of treatment in genotype 2 or 3 patients with a rapid viral response

Low viral load = ≤ 800,000 IU/ml; High viral load = > 800,000 IU/ml

RVR = rapid viral response (HCV RNA undetectable) at week 4

Superior efficacy of Reiferon Retard compared to interferon alfa-2a was demonstrated also in terms of histological response, including patients with cirrhosis and/or HIV-HCV co-infection.

Adult chronic hepatitis C prior treatment non-responder patients

In study MV17150, patients who were non-responders to previous therapy with pegylated interferon alfa-2b plus ribavirin were randomised to four different treatments:

- Reiferon Retard 360 mcg/week for 12 weeks, followed by 180 mcg/week for a further 60 weeks

- Reiferon Retard 360 mcg/week for 12 weeks, followed by 180 mcg/week for a further 36 weeks

- Reiferon Retard 180 mcg/week for 72 weeks

- Reiferon Retard 180 mcg/week for 48 weeks

All patients received ribavirin (1000 or 1200 mg/day) in combination with Reiferon Retard. All treatment arms had 24 week treatment-free follow-up.

Multiple regression and pooled group analyses evaluating the influence of treatment duration and use of induction dosing clearly identified treatment duration for 72 weeks as the primary driver for achieving a sustained virological response. Differences in sustained virological response (SVR) based on treatment duration, demographics and best responses to previous treatment are displayed in Table 19.

Table 19: Week 12 virological response (VR) and sustained virological response (SVR) in patients with virological response at week 12 after treatment with Reiferon Retard and ribavirin combination therapy in nonresponders to peginterferon alfa-2b plus ribavirin

Study MV17150
	Reiferon Retard 360/180 or 180 mcg & Ribavirin 1000/1200 mg 72 or 48 Weeks (N = 942) Pts with VR at Wk 12 a (N = 876)	Reiferon Retard 360/180 or 180 mcg & Ribavirin 1000/1200 mg 72 Weeks (N = 473) SVR in Pts with VR at Wk 12 b (N = 100)	Reiferon Retard 360/180 or 180 mcg & Ribavirin 1000/1200 mg 48 Weeks (N = 469) SVR in Pts with VR at Wk 12 b (N = 57)
Overall Low viral load High viral load	18% (157/876) 35% (56/159) 14% (97/686)	57% (57/100) 63% (22/35) 54% (34/63)	35% (20/57) 38% (8/21) 32% (11/34)
Genotype 1/4 Low viral load High viral load	17% (140/846) 35% (54/154) 13% (84/663)	55% (52/94) 63% (22/35) 52% (30/58)	Pharmacokinetic properties The information provided in Pharmacokinetic properties of Reiferon Retard is based on data of another medicine with exactly the same composition as the Reiferon Retard. . Be careful and be sure to specify the information on the section Pharmacokinetic properties in the instructions to the drug Reiferon Retard directly from the package or from the pharmacist at the pharmacy. more... Absorption Following a single subcutaneous injection of Reiferon Retard 180 micrograms in healthy subjects, serum concentrations of peginterferon alfa-2a are measurable within 3 to 6 hours. Within 24 hours, about 80% of the peak serum concentration is reached. The absorption of Reiferon Retard is sustained with peak serum concentrations reached 72 to 96 hours after dosing. The absolute bioavailability of Reiferon Retard is 84% and is similar to that seen with interferon alfa-2a. Distribution Peginterferon alfa-2a is found predominantly in the bloodstream and extracellular fluid as seen by the volume of distribution at steady-state (Vd) of 6 to 14 litres in humans after intravenous administration. From mass balance, tissue distribution and whole body autoradioluminography studies performed in rats, peginterferon alfa-2a is distributed to the liver, kidney and bone marrow in addition to being highly concentrated in the blood. Biotransformation The metabolism of Reiferon Retard is not fully characterised; however studies in rats indicate that the kidney is a major organ for excretion of radiolabelled material. Elimination In humans, the systemic clearance of peginterferon alfa-2a is about 100-fold lower than that of the native interferon alfa-2a. After intravenous administration, the terminal half-life of peginterferon alfa-2a in healthy subjects is approximately 60 to 80 hours compared to values of 3-4 hours for standard interferon. The terminal half-life after subcutaneous administration in patients is longer with a mean value of 160 hours (84 to 353 hours). The terminal half-life may not only reflect the elimination phase of the compound, but may also reflect the sustained absorption of Reiferon Retard. Linearity/non-linearity Dose-proportional increases in exposure of Reiferon Retard are seen in healthy subjects and in patients with chronic hepatitis B or C after once-weekly dosing. In CHB or CHC patients, peginterferon alfa-2a serum concentrations accumulate 2 to 3 fold after 6 to 8 weeks of once weekly dosing compared to single dose values. There is no further accumulation after 8 weeks of once weekly dosing. The peak to trough ratio after 48 weeks of treatment is about 1.5 to 2. Peginterferon alfa-2a serum concentrations are sustained throughout one full week (168 hours). Patients with renal impairment A clinical trial evaluated 50 CHC patients with either moderate (creatinine clearance 30 to 50 mL/min) or severe (creatinine clearance less than 30 mL/min) renal impairment, or with end stage renal disease (ESRD) requiring chronic hemodialysis (HD). Patients with moderate renal impairment receiving Reiferon Retard 180 mcg once weekly exhibited similar peginterferon alfa-2a plasma exposures compared to patients with normal renal function. Patients with severe renal impairment receiving Reiferon Retard 180 mcg once weekly showed a 60% higher peginterferon alfa-2a exposure than patients with normal renal function, therefore a reduced dose of Reiferon Retard 135 mcg once weekly is recommended in patients with severe renal impairment. In 13 patients with ESRD requiring chronic HD, administration of Reiferon Retard 135 mcg once weekly resulted in 34% lower peginterferon alfa-2a exposure than in patients with normal renal function. However, several independent studies have demonstrated the 135mcg dose to be safe, efficacious and well tolerated, in patients with ESRD. Gender The pharmacokinetics of Reiferon Retard after single subcutaneous injections was comparable between male and female healthy subjects. Paediatric population Reiferon Retard pharmacokinetics have been characterized in paediatric patients with CHB (YV25718), as well as in paediatric patients with CHC (NR16141), using population pharmacokinetics. In both studies, Reiferon Retard apparent clearance and apparent volume of distribution were related linearly to body size ie. either BSA (NR16141) or body weight (YV25718). From the YV25718 study, 31 paediatric patients 3 to 17 years of age with CHB participated in the PK sub-study and received Reiferon Retard according to a BSA category dosing regimen. Based on the population pharmacokinetic model, the mean exposure (AUC) during the dosing interval for each BSA category was comparable with that observed in adults receiving 180 mcg fixed dosing. From the NR16141study, 14 children 2 to 8 years of age with CHC received Reiferon Retard monotherapy at a dose of: 180 mcg x BSA of the child/1.73 m2. The PK model developed from this study shows a linear influence of BSA on the apparent clearance of the drug over the age range studied. Thus, the lower the BSA of the child, the lower the clearance of the drug and the higher the resultant exposure. The mean exposure (AUC) during the dosing interval is predicted to be 25% to 70% higher than that observed in adults receiving 180 mcg fixed dosing. Elderly In subjects older than 62 years, the absorption of Reiferon Retard after a single subcutaneous injection of 180 micrograms was delayed but still sustained compared to young healthy subjects (tmax of 115 hours vs. 82 hours, older than 62 years vs. younger, respectively). The AUC was slightly increased (1663 vs. 1295 ng·h/ml) but peak concentrations (9.1 vs. 10.3 ng/ml) were similar in subjects older than 62 years. Based on drug exposure, pharmacodynamic response and tolerability, a lower dose of Reiferon Retard is not needed in the geriatric patient. Hepatic impairment The pharmacokinetics of Reiferon Retard were similar between healthy subjects and patients with hepatitis B or C. Comparable exposure and pharmacokinetic profiles were seen in cirrhotic (Child-Pugh Grade A) and non-cirrhotic patients. Site of administration Subcutaneous administration of Reiferon Retard should be limited to the abdomen and thigh, as the extent of absorption based on AUC was about 20% to 30% higher upon injection in the abdomen and thigh. Exposure to Reiferon Retard was decreased in studies following administration of Reiferon Retard in the arm compared to administration in the abdomen and thigh. Pharmacotherapeutic group The information provided in Pharmacotherapeutic group of Reiferon Retard is based on data of another medicine with exactly the same composition as the Reiferon Retard. . Be careful and be sure to specify the information on the section Pharmacotherapeutic group in the instructions to the drug Reiferon Retard directly from the package or from the pharmacist at the pharmacy. more... Immunostimulants, interferons, ATC code: L03AB11 Preclinical safety data The information provided in Preclinical safety data of Reiferon Retard is based on data of another medicine with exactly the same composition as the Reiferon Retard. . Be careful and be sure to specify the information on the section Preclinical safety data in the instructions to the drug Reiferon Retard directly from the package or from the pharmacist at the pharmacy. more... The non-clinical toxicity studies conducted with Reiferon Retard were limited due to species specificity of interferons. Acute and chronic toxicity studies have been carried out in cynomolgus monkeys, and the findings observed in peginterferon dosed animals were similar in nature to those produced by interferon alfa-2a. Reproductive toxicity studies have not been performed with Reiferon Retard. As with other alfa interferons, prolongation of the menstrual cycle was observed following administration of peginterferon alfa-2a to female monkeys. Treatment with interferon alfa-2a resulted in a statistically significant increase in abortifacient activity in rhesus monkeys. Although no teratogenic effects were seen in the offspring delivered at term, adverse effects in humans cannot be excluded. Reiferon Retard plus ribavirin When used in combination with ribavirin, Reiferon Retard did not cause any effects in monkeys not previously seen with either active substance alone. The major treatment-related change was reversible mild to moderate anaemia, the severity of which was greater than that produced by either active substance alone. Incompatibilities The information provided in Incompatibilities of Reiferon Retard is based on data of another medicine with exactly the same composition as the Reiferon Retard. . Be careful and be sure to specify the information on the section Incompatibilities in the instructions to the drug Reiferon Retard directly from the package or from the pharmacist at the pharmacy. more... In the absence of compatibility studies, this medicinal product must not be mixed with other medicinal products. Special precautions for disposal and other handling The information provided in Special precautions for disposal and other handling of Reiferon Retard is based on data of another medicine with exactly the same composition as the Reiferon Retard. . Be careful and be sure to specify the information on the section Special precautions for disposal and other handling in the instructions to the drug Reiferon Retard directly from the package or from the pharmacist at the pharmacy. more... The solution for injection is for single use only. It should be inspected visually for particulate matter and discoloration before administration. Any unused medicinal product or waste material should be disposed of in accordance with local requirements. References: https://www.drugs.com/search.php?searchterm=reiferon-retard https://pubmed.ncbi.nlm.nih.gov/?term=reiferon-retard Available in countries Egypt Find in a country: A B C D E F G H I J K L M N O P Q R S T U V Y Z