Plaxat

Plaxat in combination with 5-fluorouracil (5-FU) and folinic acid (FA) is indicated for:

- adjuvant treatment of stage III (Dukes' C) colon cancer after complete resection of primary tumour

- treatment of metastatic colorectal cancer.

Posology

FOR ADULTS ONLY

The recommended dose for Plaxat in adjuvant setting is 85 mg/m² intravenously repeated every two weeks for 12 cycles (6 months).

The recommended dose for Plaxat in treatment of metastatic colorectal cancer is 85 mg/m² intravenously repeated every 2 weeks until disease progression or unacceptable toxicity.

Dosage given should be adjusted according to tolerability.

Plaxat should always be administered before fluoropyrimidines - i.e. 5-fluorouracil.

Plaxat is administered as a 2- to 6-hour intravenous infusion in 250 to 500 ml of 5% glucose solution to give a concentration between 0.2 mg/ml and 0.70 mg/ml; 0.70 mg/ml is the highest concentration in clinical practice for an Plaxat dose of 85 mg/m².

Plaxat was mainly used in combination with continuous infusion 5-fluorouracil based regimens. For the two-weekly treatment schedule 5-fluorouracil regimens combining bolus and continuous infusion were used.

Special Populations

Renal impairment:

Plaxat must not be administered in patients with severe renal impairment. In patients with mild to moderate renal impairment, the recommended dose of Plaxat is 85 mg/m².

Hepatic impairment:

In a phase I study including patients with several levels of hepatic impairment, frequency and severity of hepato-biliary disorders appeared to be related to progressive disease and impaired liver function tests at baseline. No specific dose adjustment for patients with abnormal liver function tests was performed during clinical development.

Elderly patients:

No increase in severe toxicities was observed when Plaxat was used as a single agent or in combination with 5-fluorouracil in patients over the age of 65. In consequence no specific dose adaptation is required for elderly patients.

Paediatric population:

There is no relevant indication for use of Plaxat in children. The effectiveness of Plaxat single agent in the paediatric populations with solid tumours has not been established.

Method of administration

Plaxat is administered by intravenous infusion.

The administration of Plaxat does not require hyperhydration.

Plaxat diluted in 250 to 500 ml of 5% glucose solution to give a concentration not less than 0.2 mg/ml must be infused via a central venous line or peripheral vein over 2 to 6 hours.

Plaxat infusion must always precede the administration of 5-fluorouracil.

Instruction for use

Plaxat must be diluted before use. Only 5% glucose diluent is to be used to dilute the concentrate for solution for infusion product..

In the event of extravasation, administration must be discontinued immediately.

Plaxat is contraindicated in patients who:

- are breast feeding

- have myelosuppression prior to starting first course, as evidenced by baseline neutrophils <2x10⁹/l and/or platelet count of <100x10⁹l

- have a peripheral sensitive neuropathy with functional impairment prior to first course

- have a severely impaired renal function (creatinine clearance less than 30 ml/min).

Renal impairment

Patients with mild to moderate renal impairment should be closely monitored for adverse reactions and the dose adjusted according to toxicity.

Hypersensitivity reactions

Special surveillance should be ensured for patients with a history of allergic manifestations to other products containing platinum. In case of anaphylactic manifestations the infusion should be interrupted immediately and an appropriate symptomatic treatment started. Re-administration of Plaxat is contra-indicated. Cross reactions, sometimes fatal, have been reported with all platinum compounds.

In case of Plaxat extravasation, the infusion must be stopped immediately and usual local symptomatic treatment initiated.

Neurological symptoms

Neurological toxicity of Plaxat should be carefully monitored, especially if co-administered with other medications with specific neurological toxicity. A neurological examination should be performed before each administration and periodically thereafter.

For patients who develop acute laryngopharyngeal dysaesthesia , during or within the hours following the 2-hour infusion, the next Plaxat infusion should be administered over 6 hours.

Peripheral neuropathy

If neurological symptoms (paraesthesia, dysaesthesia) occur, the following recommended Plaxat dosage adjustment should be based on the duration and severity of these symptoms:

- if symptoms last longer than seven days and are troublesome, the subsequent Plaxat dose should be reduced from 85 to 65 mg/m² (metastatic setting) or 75 mg/m² (adjuvant setting)

- if paraesthesia without functional impairment persists until the next cycle, the subsequent Plaxat dose should be reduced from 85 to 65 mg/m² (metastatic setting) or 75 mg/m² (adjuvant setting)

- if paraesthesia with functional impairment persists until the next cycle, Plaxat should be discontinued

- if these symptoms improve following discontinuation of Plaxat therapy, resumption of therapy may be considered.

Patients should be informed of the possibility of persistent symptoms of peripheral sensory neuropathy after the end of the treatment. Localized moderate paresthesias or paresthesias that may interfere with functional activities can persist after up to 3 years following treatment cessation in the adjuvant setting.

Reversible Posterior Leukoencephalopathy Syndrome (RPLS)

Cases of Reversible Posterior Leukoencephalopathy Syndrome (RPLS also known as PRES, Posterior Reversible Encephalopathy Syndrome) have been reported in patients receiving Plaxat in combination chemotherapy. RPLS is a rare, reversible, rapidly evolving neurological condition, which can include seizure, hypertension, headache, confusion, blindness, and other visual and neurological disturbances. Diagnosis of RPLS is based upon confirmation by brain imaging, preferably MRI (Magnetic Resonance Imaging).

Nausea, vomiting, diarrhoea, dehydration and haematological changes

Gastrointestinal toxicity, which manifests as nausea and vomiting, warrants prophylactic and/or therapeutic anti-emetic therapy.

Dehydration, paralytic ileus, intestinal obstruction, hypokalemia, metabolic acidosis and renal impairment may be caused by severe diarrhoea/emesis particularly when combining Plaxat with 5-fluorouracil.

Cases of intestinal ischemia, including fatal outcomes, have been reported with Plaxat treatment. In case of intestinal ischemia, Plaxat treatment should be discontinued and appropriate measures initiated.

If haematological toxicity occurs (neutrophils < 1.5x10⁹/l or platelets < 50x10⁹/l), administration of the next course of therapy should be postponed until haematological values return to acceptable levels. A full blood count with white cell differential should be performed prior to start of therapy and before each subsequent course. Myelosuppressive effects may be additive to those of concomitant chemotherapy. Patient with severe and persistent myelosuppression are at high risk of infectious complications. Sepsis, neutropenic sepsis and septic shock have been reported in patients treated with Plaxat including fatal outcomes. If any of these events occurs, Plaxat should be discontinued.

Patients must be adequately informed of the risk of diarrhoea/emesis, mucositis/ stomatitis and neutropenia after Plaxat and 5-fluorouracil administration so that they can urgently contact their treating physician for appropriate management.

If mucositis/ stomatitis occurs with or without neutropenia, the next treatment should be delayed until recovery from mucositis/ stomatitis to grade 1 or less and/or until the neutrophil count is > 1.5 x 10⁹/l.

For Plaxat combined with 5-fluorouracil (with or without folinic acid), the usual dose adjustments for 5-fluorouracil associated toxicities should apply.

If grade 4 diarrhoea, grade 3-4 neutropenia (neutrophils <1.0x10⁹/l), febrile neutropenia (fever of unknown origin without clinically or microbiologically documented infection with an absolute neutrophil count < 1.0 x 10⁹/L, temperature > 38.3°C or a sustained temperature > 38°C for more than one hour), or grade 3-4 thrombocytopenia (platelets < 50x10⁹/l) occur, the dose of Plaxat should be reduced from 85 to 65 mg/m² (metastatic setting) or 75 mg/m² (adjuvant setting), in addition to any 5-fluorouracil dose reductions required.

Pulmonary

In the case of unexplained respiratory symptoms such as non-productive cough, dyspnoea, crackles or radiological pulmonary infiltrates, Plaxat should be discontinued until further pulmonary investigations exclude an interstitial lung disease.

Blood disorders

Haemolytic-uraemic syndrome (HUS) is a life-threatening side effect (frequency not known). Plaxat should be discontinued at the first signs of any evidence of microangiopathic haemolytic anaemia, such as rapidly falling haemoglobin with concomitant thrombocytopenia, elevation of serum bilirubin, serum creatinine, blood urea nitrogen, or LDH. Renal failure may not be reversible with discontinuation of therapy and dialysis may be required. Disseminated intravascular coagulation (DIC), including fatal outcomes, has been reported in association with Plaxat treatment. If DIC is present, Plaxat treatment should be discontinued and appropriate treatment should be administered.

QT prolongation

QT prolongation may lead to an increased risk for ventricular arrhythmias including Torsade de Pointes, which can be fatal. The QT interval should be closely monitored on a regular basis before and after administration of Plaxat. Caution should be exercised in patients with a history or a predisposition for prolongation of QT, those who are taking medicinal products known to prolong QT interval, and those with electrolyte disturbances such as hypokalemia, hypocalcaemia, or hypomagnesaemia. In case of QT prolongation, Plaxat treatment should be discontinued.

Rhabdomyolysis

Rhabdomyolysis has been reported in patients treated with Plaxat, including fatal outcomes. In case of muscle pain and swelling, in combination with weakness, fever or darkened urine, Plaxat treatment should be discontinued. If rhabdomyolysis is confirmed, appropriate measures should be taken. Caution is recommended if medicinal products associated with rhabdomyolysis are administered concomitantly with Plaxat.

Gastrointestinal ulcer/ Gastrointestinal ulcer haemorrhage and perforation

Plaxat treatment can cause gastrointestinal ulcer and potential complications, such as gastrointestinal haemorrhage and perforation, which can be fatal. In case of gastrointestinal ulcer, Plaxat treatment should be discontinued and appropriate measures taken.

Hepatic

In case of abnormal liver function test results or portal hypertension which does not obviously result from liver metastases, very rare cases of drug-induced hepatic vascular disorders should be considered.

Pregnancy

Fertility

Genotoxic effects were observed with Plaxat in the preclinical studies. Therefore male patients treated with Plaxat are advised not to father a child during and up to 6 months after treatment and to seek advice on conservation of sperm prior to treatment because Plaxat may have an anti-fertility effect which could be irreversible.

Women should not become pregnant during treatment with Plaxat and should use an effective method of contraception.

Immunosuppressant effects/increased susceptibility to infections:

Administration of live or live-attenuated vaccines in patients immunocompromised by chemotherapeutic agents including Plaxat, may result in serious or fatal infections. Vaccination with a live vaccine should be avoided in patients receiving Plaxat. Killed or inactivated vaccines may be administered; however, the response to such vaccines may be diminished.

No studies on the effects on the ability to drive and use machines have been performed. However Plaxat treatment resulting in an increase risk of dizziness, nausea and vomiting, and other neurologic symptoms that affect gait and balance may lead to a minor or moderate influence on the ability to drive and use machines.

Vision abnormalities, in particular transient vision loss (reversible following therapy discontinuation), may affect patients' ability to drive and use machines. Therefore, patients should be warned of the potential effect of these events on the ability to drive or use machines.

Summary of the safety profile

The most frequent adverse events of Plaxat in combination with 5-fluorouracil/folinic acid (5-FU/FA) were gastrointestinal (diarrhoea, nausea, vomiting and mucositis), haematological (neutropenia, thrombocytopenia) and neurological (acute and dose cumulative peripheral sensory neuropathy). Overall, these adverse events were more frequent and severe with Plaxat and 5-FU/FA combination than with 5-FU/FA alone.

Tabulated list of adverse reactions

The frequencies reported in the table below are derived from clinical trials in the metastatic and adjuvant settings (having included 416 and 1108 patients respectively in the Plaxat + 5-FU/FA treatment arms) and from post marketing experience.

Frequencies in this table are defined using the following convention: very common (>1/10) common (>1/100, <1/10), uncommon (>1/1000, ≤1/100), rare (>1/10000, ≤1/1000), very rare (≤1/10000), not known (cannot be estimated from the available data).

Further details are given after the table.

* See detailed section below

<

+ including fatal outcomes

++ Very common allergies/allergic reactions, occurring mainly during infusion, sometimes fatal. Common allergic reactions include skin rash, particularly urticaria, conjunctivitis ,and rhinitis. Common anaphylactic or anaphylactoid reactions include bronchospasm, angiooedema, hypotension, sensation of chest pain and anaphylactic shock. Delayed hypersensitivity has also been reported with Plaxat hours or even days after the infusion.

+++ Very common fever, rigors (tremors), either from infection (with or without febrile neutropenia) or possibly from immunological mechanism.

++++ Injection site reactions including local pain, redness, swelling and thrombosis have been reported. Extravasation may also result in local pain and inflammation which may be severe and lead to complications including necrosis, especially when Plaxat is infused through a peripheral vein.

Description of selected adverse reactions

Blood and lymphatic system disorders

Incidence by patient (%), by grade

Rare (>1/10000, <1/1000)

Disseminated intravascular coagulation (DIC), including fatal outcomes.

Post marketing experience with frequency unknown

Hemolytic uremic syndrome, autoimmune pancytopenia.

Infections and infestations

Incidence by patient (%), by grade

Post-marketing experience with frequency not known

Septic shock, including fatal outcomes.

Immune system disorders

Incidence of allergic reactions by patient (%), by grade

Nervous system disorders

The dose limiting toxicity of Plaxat is neurological. It involves a sensory peripheral neuropathy characterized by dysaesthesia and/or paraesthesia of the extremities with or without cramps, often triggered by the cold.

These symptoms occur in up to 95% of patients treated. The duration of these symptoms, which usually regress between courses of treatment, increases with the number of treatment cycles.

The onset of pain and/or a functional disorder are indications, depending on the duration of the symptoms, for dose adjustment, or even treatment discontinuation.

This functional disorder includes difficulties in executing delicate movements and is a possible consequence of sensory impairment. The risk of occurrence of persistent symptoms for a cumulative dose of 850 mg/m² (10 cycles) is approximately 10% and 20% for a cumulative dose of 1020 mg/m² (12 cycles).

In the majority of the cases, the neurological signs and symptoms improve or totally recover when treatment is discontinued. In the adjuvant setting of colon cancer, 6 months after treatment cessation, 87 % of patients had no or mild symptoms. After up to 3 years of follow up, about 3 % of patients presented either with persisting localized paresthesias of moderate intensity (2.3%) or with paresthesias that may interfere with functional activities (0.5%).

Acute neurosensory manifestations have been reported. They start within hours of administration and often occur on exposure to cold. They usually present as transient paresthesia, dysesthesia and hypoesthesia. An acute syndrome of pharyngolaryngeal dysesthesia occurs in 1% - 2% of patients and is characterised by subjective sensations of dysphagia or dyspnoea/feeling of suffocation, without any objective evidence of respiratory distress (no cyanosis or hypoxia) or of laryngospasm or bronchospasm (no stridor or wheezing). Although antihistamines and bronchodilators have been administered in such cases, the symptoms are rapidly reversible even in the absence of treatment. Prolongation of the infusion helps to reduce the incidence of this syndrome. Occasionally other symptoms that have been observed include jaw spasm/muscle spasms/muscle contractions-involuntary/muscle twitching/myoclonus, coordination abnormal/gait abnormal/ ataxia/ balance disorders, throat or chest tightness/ pressure/ discomfort/pain. In addition, cranial nerve dysfunctions may be associated with above mentioned events, or also occur as an isolated event such as ptosis, diplopia, aphonia/ dysphonia/ hoarseness, sometimes described as vocal cord paralysis, abnormal tongue sensation or dysarthria, sometimes described as aphasia, trigeminal neuralgia/ facial pain/ eye pain, decrease in visual acuity, visual field disorders.

Other neurological symptoms such as dysarthria, loss of deep tendon reflex and Lhermitte's sign were reported during treatment with Plaxat. Isolated cases of optic neuritis have been reported.

Post marketing experience with frequency unknown

Convulsion

Cardiac disorders

Post-marketing experience with frequency not known

QT prolongation, which may lead to ventricular arrhythmias including Torsade de Pointes, which may be fatal.

Respiratory, thoracic and mediastinal disorders

Post-marketing experience with frequency not known:

Laryngospasm

Gastrointestinal disorders

Incidence by patient (%), by grade

Prophylaxis and/or treatment with potent antiemetic agents is indicated.

Dehydration, paralytic ileus, intestinal obstruction, hypokalaemia, metabolic acidosis and renal impairment may be caused by severe diarrhoea/emesis particularly when combining Plaxat with 5 fluorouracil (5 FU).

Post marketing experience with frequency not known

Intestinal ischaemia, including fatal outcomes.

Gastrointestinal ulcer and perforation, which can be fatal.

Hepato-biliary disorders

Very rare (≤ 1/10000)

Liver sinusoidal obstruction syndrome, also known as veno-occlusive disease of liver or pathological manifestations related to such liver disorder, including peliosis hepatis, nodular regenerative hyperplasia, perisinusoidal fibrosis. Clinical manifestations may be portal hypertension and/or increased transaminases.

Musculoskeletal and connective tissue disorders

Post-marketing experience with frequency not known

Rhabdomyolysis, including fatal outcomes.

Skin and subcutaneous tissue disorders

Post-marketing experience with frequency not known

Hypersensitivity vasculitis.

Renal and urinary disorders

Very rare (≤ 1/10000)

Acute tubular necrosis, acute interstitial nephritis and acute renal failure.

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 via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

There is no known antidote to Plaxat. In cases of overdose, exacerbation of adverse events can be expected. Monitoring of haematological parameters should be initiated and symptomatic treatment given.

Pharmacotherapeutic group: other antineoplastic agents, platinum compounds

ATC code: L01XA 03

Mechanism of action

Plaxat is an antineoplastic active substance belonging to a new class of platinum-based compounds in which the platinum atom is complexed with 1,2-diaminocyclohexane (“DACH”) and an oxalate group.

Plaxat is a single enantiomer, (SP-4-2)-[(1R,2R)-Cyclohexane-1,2-diamine-kN, kN'] [ethanedioato(2-)-kO¹, kO²] platinum.

Plaxat exhibits a wide spectrum of both in vitro cytotoxicity and in vivo anti-tumour activity in a variety of tumour model systems including human colorectal cancer models. Plaxat also demonstrates in vitro and in vivo activity in various cisplatin resistant models.

A synergistic cytotoxic action has been observed in combination with 5-fluorouracil both in vitro and in vivo.

Studies on the mechanism of action of Plaxat, although not completely elucidated, show that the aqua-derivatives resulting from the biotransformation of Plaxat, interact with DNA to form both inter and intra-strand cross-links, resulting in the disruption of DNA synthesis leading to cytotoxic and anti-tumour effects.

Clinical and efficacy and safety

In patients with metastatic colorectal cancer, the efficacy of Plaxat (85 mg/m² repeated every two weeks) combined with 5-fluorouracil/folinic acid (5-FU/FA) is reported in three clinical studies:

- in front-line treatment, the 2-arm comparative phase III EFC2962 study randomised 420 patients either to 5-FU/FA alone (LV5FU2, N=210) or the combination of Plaxat with 5-FU/FA (FOLFOX4, N=210)

- in pretreated patients, the comparative three arms phase III study EFC4584 randomised 821 patients refractory to an irinotecan (CPT-11) + 5-FU/FA combination either to 5-FU/FA alone (LV5FU2, N=275), Plaxat single agent (N=275), or combination of Plaxat with 5-FU/FA (FOLFOX4, N=271).

- finally, the uncontrolled phase II EFC2964 study included patients refractory to 5-FU/FA alone, that were treated with the Plaxat and 5-FU/FA combination (FOLFOX4, N=57).

The two randomised clinical trials, EFC2962 in front-line therapy and EFC4584 in pretreated patients, demonstrated a significantly higher response rate and a prolonged progression free survival (PFS)/time to progression (TTP) as compared to treatment with 5-FU/FA alone. In EFC4584 performed in refractory pretreated patients, the difference in median overall survival (OS) between the combination of Plaxat and 5-FU/FA did not reach statistical significance.

Response rate under FOLFOX4 versus LV5FU2

* NA : Not Applicable

Median Progression Free Survival (PFS) / Median Time to Progression (TTP) FOLFOX4 versus LV5FU2

*NA : Not Applicable

Median Overall Survival (OS) under FOLFOX4 versus LV5FU2

*NA : Not Applicable

In pretreated patients (EFC4584), who were symptomatic at baseline, a higher proportion of those treated with Plaxat and 5-FU/FA experienced a significant improvement of their disease related symptoms compared to those treated with 5-FU/FA alone (27.7% versus 14.6% p = 0.0033).

In non-pretreated patients (EFC2962), no statistically significant difference between the two treatment groups was found for any of the quality of life dimensions. However, the quality of life scores were generally better in the control arm for measurement of global health status and pain and worse in the Plaxat arm for nausea and vomiting. In the adjuvant setting, the MOSAÏC comparative phase III study (EFC3313) randomised 2246 patients (899 stage II/Dukes' B2 and 1347 stage III/Dukes' C) further to complete resection of the primary tumour of colon cancer either to 5-FU/FA alone (LV5FU2, N=1123 ( B2/C = 448/675) or to combination of Plaxat and 5-FU/FA (FOLFOX4, N=1123 (B2/C) = 451/672).

EFC 3313 3-year disease free survival (ITT analysis )* for the overall population.

* median follow up 44.2 months (all patients followed for at least 3 years)

The study demonstrated an overall significant advantage in 3-year disease free survival for the Plaxat and 5-FU/FA combination (FOLFOX4) over 5-FU/FA alone (LV5FU2).

EFC 3313 3-year disease free survival (ITT analysis )* according to stage of disease.

* median follow up 44.2 months (all patients followed for at least 3 years)

Overall Survival (ITT analysis)

At time of the analysis of the 3-year disease free survival, which was the primary endpoint of the MOSAIC trial, 85.1% of the patients were still alive in the FOLFOX4 arm versus 83.8% in the LV5FU2 arm. This translated into an overall reduction in mortality risk of 10% in favour of FOLFOX4 not reaching statistical significance (hazard ratio = 0.90). The figures were 92.2% versus 92.4% in the stage II (Dukes' B2) sub-population (hazard ratio = 1.01) and 80.4% versus 78.1% in the stage III (Dukes' C) sub-population (hazard ratio = 0.87), for FOLFOX4 and LV5FU2, respectively.

Paediatric population

Plaxat single agent has been evaluated in paediatric population in 2 Phase I (69 patients) and 2 Phase II (166 patients) studies. A total of 235 paediatric patients (7 months - 22 years of age) with solid tumours have been treated. The effectiveness of Plaxat single agent in the paediatric populations treated has not been established. Accrual in both Phase II studies was stopped for lack of tumour response.

The pharmacokinetics of individual active compounds have not been determined. The pharmacokinetics of ultrafiltrable platinum, representing a mixture of all unbound, active and inactive platinum species, following a two-hour infusion of Plaxat at 130 mg /m² every three weeks for 1 to 5 cycles and Plaxat at 85 mg/m² every two weeks for 1 to 3 cycles are as follows:

Summary of Platinum Pharmacokinetic Parameter Estimates in Ultrafiltrate Following Multiple Doses of Plaxat at 85 mg/m² Every Two Weeks or at 130 mg/m² Every Three Weeks

Mean AUC_0-48, and C_max values were determined on Cycle 3 (85 mg/m²) or cycle 5 (130 mg/m²).

Mean AUC, Vss, CL, and CL_R0-48 values were determined on Cycle 1.

C_end, C_max, AUC, AUC_0-48, Vss and CL values were determined by non-compartmental analysis.

t_1/2α, t_1/2β, and t_1/2γ, were determined by compartmental analysis (Cycles 1-3 combined).

At the end of a 2-hour infusion, 15% of the administered platinum is present in the systemic circulation, the remaining 85% being rapidly distributed into tissues or eliminated in the urine. Irreversible binding to red blood cells and plasma, results in half-lives in these matrices that are close to the natural turnover of red blood cells and serum albumin. No accumulation was observed in plasma ultrafiltrate following 85 mg/m² every two weeks or 130 mg/m² every three weeks and steady state was attained by cycle one in this matrix. Inter- and intra-subject variability is generally low.

Biotransformation in vitro is considered to be the result of non-enzymatic degradation and there is no evidence of cytochrome P450-mediated metabolism of the diaminocyclohexane (DACH) ring.

Plaxat undergoes extensive biotransformation in patients, and no intact drug was detectable in plasma ultrafiltrate at the end of a 2h-infusion. Several cytotoxic biotransformation products including the monochloro-, dichloro- and diaquo-DACH platinum species have been identified in the systemic circulation together with a number of inactive conjugates at later time points. Platinum is predominantly excreted in urine, with clearance mainly in the 48 hours following administration. By day 5, approximately 54% of the total dose was recovered in the urine and < 3% in the faeces.

The effect of renal impairment on the disposition of Plaxat was studied in patients with varying degrees of renal function. Plaxat was administered at a dose of 85 mg/m² in the control group with a normal renal function (CLcr > 80 ml/min, n=12) and in patients with mild (CLcr = 50 to 80 ml/min, n=13) and moderate (CLcr = 30 to 49 ml/min, n=11) renal impairment, and at a dose of 65 mg/m² in patients with severe renal impairment (CLcr < 30 ml/min, n=5). Median exposure was 9, 4, 6, and 3 cycles, respectively, and PK data at cycle 1 were obtained in 11, 13, 10, and 4 patients respectively.

There was an increase in plasma ultrafiltrate (PUF) platinum AUC, AUC/dose and a decrease in total and renal CL and Vss with increasing renal impairment especially in the (small) group of patients with severe renal impairment: point estimate (90% CI) of estimated mean ratios by renal status versus normal renal function for AUC/dose were 1.36 (1.08, 1.71), 2.34 (1.82, 3.01) and 4.81 (3.49, 6.64) for patients with mild and moderate and in severe renal failure respectively.

Elimination of Plaxat is significantly correlated with the creatinine clearance. Total PUF platinum CL was respectively 0.74 (0.59, 0.92), 0.43 (0.33, 0.55) and 0.21 (0.15, 0.29) and for Vss respectively 0.52 (0.41, 0.65), 0.73 (0.59, 0.91) and 0.27 (0.20, 0.36) for patients with mild, moderate and severe renal failure respectively. Total body clearance of PUF platinum was therefore reduced by respectively 26% in mild, 57% in moderate, and 79% in severe renal impairment compared to patients with normal function.

Renal clearance of PUF platinum was reduced in patients with impaired renal function by 30% in mild, 65% in moderate, and 84% in severe renal impairment compared to patients with normal function.

There was an increase in beta half life of PUF platinum with increasing degree of renal impairment mainly in the severe group. Despite the small number of patients with severe renal dysfunction, these data are of concern in patients in severe renal failure and should be taken into account when prescribing Plaxat in patients with renal impairment.

The target organs identified in preclinical species (mice, rats, dogs, and/or monkeys) in single- and multiple-dose studies included the bone marrow, the gastrointestinal system, the kidney, the testes, the nervous system, and the heart. The target organ toxicities observed in animals are consistent with those produced by other platinum-containing drugs and DNA-damaging, cytotoxic drugs used in the treatment of human cancers with the exception of the effects produced on the heart. Effects on the heart were observed only in the dog and included electrophysiological disturbances with lethal ventricular fibrillation. Cardiotoxicity is considered specific to the dog not only because it was observed in the dog alone but also because doses similar to those producing lethal cardiotoxicity in dogs (150 mg/m²) were well-tolerated by humans. Preclinical studies using rat sensory neurons suggest that the acute neurosensory symptoms related to Plaxat may involve an interaction with voltage-gated Na⁺ channels.

Plaxat was mutagenic and clastogenic in mammalian test systems and produced embryo-fetal toxicity in rats. Plaxat is considered a probable carcinogen, although carcinogenic studies have not been conducted.

As with other potentially toxic compounds, caution should be exercised when handling and preparing Plaxat solutions.

Instructions for handling

The handling of this cytotoxic agent by healthcare personnel requires every precaution to guarantee the protection of the handler and his surroundings.

The preparation of injectable solutions of cytotoxic agents must be carried out by trained specialist personnel with knowledge of the medicines used, in conditions that guarantee the integrity of the medicinal product, the protection of the environment and in particular the protection of the personnel handling the medicines, in accordance with the hospital policy. It requires a preparation area reserved for this purpose. It is forbidden to smoke, eat or drink in this area.

Personnel must be provided with appropriate handling materials, notably long sleeved gowns, protection masks, caps, protective goggles, sterile single-use gloves, protective covers for the work area, containers and collection bags for waste.

Excreta and vomit must be handled with care.

Pregnant women must be warned to avoid handling cytotoxic agents.

Any broken container must be treated with the same precautions and considered as contaminated waste. Contaminated waste should be incinerated in suitably labelled rigid containers. See below chapter “Disposal”.

If Plaxat concentrate or infusion solution, should come into contact with skin, wash immediately and thoroughly with water.

If Plaxat concentrate or infusion solution, should come into contact with mucous membranes, wash immediately and thoroughly with water.

Special precautions for administration

- DO NOT use injection equipment containing aluminium.

- DO NOT administer undiluted.

- Only glucose 5 % (50 mg/ml) infusion solution is to be used as a diluent. DO NOT dilute for infusion with sodium chloride or chloride containing solutions.

- DO NOT mix with any other medicinal products in the same infusion bag or administer simultaneously by the same infusion line.

- DO NOT mix with alkaline medicinal products or solutions, in particular 5-fluorouracil, folinic acid preparations containing trometamol as an excipient and trometamol salts of others active substances. Alkaline medicinal products or solutions will adversely affect the stability of Plaxat.

Instruction for use with folinic acid (as calcium folinate or disodium folinate)

Plaxat 85 mg/m² intravenous infusion in 250 to 500 ml of glucose 5 % (50 mg/ml) solution is given at the same time as folinic acid (FA) intravenous infusion in glucose 5 % solution, over 2 to 6 hours, using a Y-line placed immediately before the site of infusion.

These two medicinal products should not be combined in the same infusion bag. Folinic acid (FA) must not contain trometamol as an excipient and must only be diluted using isotonic glucose 5 % solution, never in alkaline solutions or sodium chloride or chloride containing solutions.

Instruction for use with 5 fluorouracil (5 FU)

Plaxat should always be administered before fluoropyrimidines - i.e. 5 fluorouracil (5 FU).

After Plaxat administration, flush the line and then administer 5 fluorouracil (5 FU).

For additional information on medicinal products combined with Plaxat, see the corresponding manufacturer's summary of product characteristics.

Concentrate for solution for infusion

Inspect visually prior to use. Only clear solutions without particles should be used.

The medicinal product is for single use only. Any unused concentrate should be discarded.

Instructions for dilution

Withdraw the required amount of concentrate from the vial(s) and then dilute with 250 ml to 500 ml of a 5% glucose solution to give an Plaxat concentration between not less than 0.2 mg/ml and 0.7 mg/ml. The concentration range for which the physico-chemical stability of Plaxat has been demonstrated is 0.2 mg/ml to 0.7 mg/ml.

Administer by intravenous infusion.

Chemical and physical in-use stability has been demonstrated for 24 hours at room temperature (15-25°C) or for 48 hours under refrigeration (2°C-8°C). From a microbiological point of view, this infusion preparation should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 2 °C to 8°C unless dilution has taken place in controlled and validated aseptic conditions.

Inspect visually prior to use. Only clear solutions without particles should be used.

The medicinal product is for single use only. Any unused infusion solution should be discarded.

NEVER use sodium chloride or chloride containing solutions for dilution.

The compatibility of Plaxat solution for infusion has been tested with representative, PVC based, administrative sets.

Infusion

The administration of Plaxat does not require prehydration.

Plaxat diluted in 250 to 500 ml of a 5% glucose solution to give a concentration not less than 0.2 mg/ml must be infused either by peripheral vein or central venous line over 2 to 6 hours. When Plaxat is administered with 5-fluorouracil, the Plaxat infusion must precede the administration of 5-fluorouracil.

Disposal

Any unused medicinal product or waste material should be disposed of according to standard procedures applicable to cytotoxic agents in accordance with local requirements.