Components:
Method of action:
Treatment option:
Medically reviewed by Militian Inessa Mesropovna, PharmD. Last updated on 12.03.2022
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Thiophosphamide is indicated, in combination with other chemotherapy medicinal products:
- with or without total body irradiation (TBI), as conditioning treatment prior to allogeneic or autologous haematopoietic progenitor cell transplantation (HPCT) in haematological diseases in adult and paediatric patients;
- when high dose chemotherapy with HPCT support is appropriate for the treatment of solid tumours in adult and paediatric patients.
Thiophosphamide administration must be supervised by a physician experienced in conditioning treatment prior to haematopoietic progenitor cell transplantation.
Posology
Thiophosphamide is administered at different doses, in combination with other chemotherapeutic medicinal products, in patients with haematological diseases or solid tumours prior to HPCT.
Thiophosphamide posology is reported, in adult and paediatric patients, according to the type of HPCT (autologous or allogeneic) and disease.
Adults
AUTOLOGOUS HPCT
Haematological diseases
The recommended dose in haematological diseases ranges from 125 mg/m2/day (3.38 mg/kg/day) to 300 mg/m2/day (8.10 mg/kg/day) as a single daily infusion, administered from 2 up to 4 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 900 mg/m2 (24.32 mg/kg), during the time of the entire conditioning treatment.
LYMPHOMA
The recommended dose ranges from 125 mg/m2/day (3.38 mg/kg/day) to 300 mg/m2/day (8.10 mg/kg/day) as a single daily infusion, administered from 2 up to 4 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 900 mg/m2 (24.32 mg/kg), during the time of the entire conditioning treatment.
CENTRAL NERVOUS SYSTEM (CNS) LYMPHOMA
The recommended dose is 185 mg/m2/day (5 mg/kg/day) as a single daily infusion, administered for 2 consecutive days before autologous HPCT, without exceeding the total maximum cumulative dose of 370 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
MULTIPLE MYELOMA
The recommended dose ranges from 150 mg/m2/day (4.05 mg/kg/day) to 250 mg/m2/day (6.76 mg/kg/day) as a single daily infusion, administered for 3 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 750 mg/m2 (20.27 mg/kg), during the time of the entire conditioning treatment.
Solid tumours
The recommended dose in solid tumours ranges from 120 mg/m2/day (3.24 mg/kg/day) to 250 mg/m2/day (6.76 mg/kg/day) divided in one or two daily infusions, administered from 2 up to 5 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 800 mg/m2 (21.62 mg/kg), during the time of the entire conditioning treatment.
BREAST CANCER
The recommended dose ranges from 120 mg/m2/day (3.24 mg/kg/day) to 250 mg/m2/day (6.76 mg/kg/day) as a single daily infusion, administered from 3 up to 5 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 800 mg/m2 (21.62 mg/kg), during the time of the entire conditioning treatment.
CNS TUMOURS
The recommended dose ranges from 125 mg/m2/day (3.38 mg/kg/day) to 250 mg/m2/day (6.76 mg/kg/day) divided in one or two daily infusions, administered from 3 up to 4 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 750 mg/m2 (20.27 mg/kg), during the time of the entire conditioning treatment.
OVARIAN CANCER
The recommended dose is 250 mg/m2/day (6.76 mg/kg/day) as a single daily infusion, administered in 2 consecutive days before autologous HPCT, without exceeding the total maximum cumulative dose of 500 mg/m2 (13.51 mg/kg), during the time of the entire conditioning treatment.
GERM CELL TUMOURS
The recommended dose ranges from 150 mg/m2/day (4.05 mg/kg/day) to 250 mg/m2/day (6.76 mg/kg/day) as a single daily infusion, administered for 3 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 750 mg/m2 (20.27 mg/kg), during the time of the entire conditioning treatment.
ALLOGENEIC HPCT
Haematological diseases
The recommended dose in haematological diseases ranges from 185 mg/m2/day (5 mg/kg/day) to 481 mg/m2/day (13 mg/kg/day) divided in one or two daily infusions, administered from 1 up to 3 consecutive days before allogeneic HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 555 mg/m2 (15 mg/kg), during the time of the entire conditioning treatment.
LYMPHOMA
The recommended dose in lymphoma is 370 mg/m2/day (10 mg/kg/day) divided in two daily infusions before allogeneic HPCT, without exceeding the total maximum cumulative dose of 370 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
MULTIPLE MYELOMA
The recommended dose is 185 mg/m2/day (5 mg/kg/day) as a single daily infusion before allogeneic HPCT, without exceeding the total maximum cumulative dose of 185 mg/m2 (5 mg/kg), during the time of the entire conditioning treatment.
LEUKAEMIA
The recommended dose ranges from 185 mg/m2/day (5 mg/kg/day) to 481 mg/m2/day (13 mg/kg/day) divided in one or two daily infusions, administered from 1 up to 2 consecutive days before allogeneic HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 555 mg/m2 (15 mg/kg), during the time of the entire conditioning treatment.
THALASSEMIA
The recommended dose is 370 mg/m2/day (10 mg/kg/day) divided in two daily infusions, administered before allogeneic HPCT, without exceeding the total maximum cumulative dose of 370 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
Paediatric population
AUTOLOGOUS HPCT
Solid tumours
The recommended dose in solid tumours ranges from 150 mg/m2/day (6 mg/kg/day) to 350 mg/m2/day (14 mg/kg/day) as a single daily infusion, administered from 2 up to 3 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 1050 mg/m2 (42 mg/kg), during the time of the entire conditioning treatment.
CNS TUMOURS
The recommended dose ranges from 250 mg/m2/day (10 mg/kg/day) to 350 mg/m2/day (14 mg/kg/day) as a single daily infusion, administered for 3 consecutive days before autologous HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 1050 mg/m2 (42 mg/kg), during the time of the entire conditioning treatment.
ALLOGENEIC HPCT
Haematological diseases
The recommended dose in haematological diseases ranges from 125 mg/m2/day (5 mg/kg/day) to 250 mg/m2/day (10 mg/kg/day) divided in one or two daily infusions, administered from 1 up to 3 consecutive days before allogeneic HPCT depending on the combination with other chemotherapeutic medicinal products, without exceeding the total maximum cumulative dose of 375 mg/m2 (15 mg/kg), during the time of the entire conditioning treatment.
LEUKAEMIA
The recommended dose is 250 mg/m2/day (10 mg/kg/day) divided in two daily infusions, administered before allogeneic HPCT, without exceeding the total maximum cumulative dose of 250 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
THALASSEMIA
The recommended dose ranges from 200 mg/m2/day (8 mg/kg/day) to 250 mg/m2/day (10 mg/kg/day) divided in two daily infusions, administered before allogeneic HPCT without exceeding the total maximum cumulative dose of 250 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
REFRACTORY CYTOPENIA
The recommended dose is 125 mg/m2/day (5 mg/kg/day) as a single daily infusion, administered for 3 consecutive days before allogeneic HPCT, without exceeding the total maximum cumulative dose of 375 mg/m2 (15 mg/kg), during the time of the entire conditioning treatment.
GENETIC DISEASES
The recommended dose is 125 mg/m2/day (5 mg/kg/day) as a single daily infusion, administered for 2 consecutive days before allogeneic HPCT, without exceeding the total maximum cumulative dose of 250 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
SICKLE CELL ANAEMIA
The recommended dose is 250 mg/m2/day (10 mg/kg/day) divided in two daily infusions, administered before allogeneic HPCT, without exceeding the total maximum cumulative dose of 250 mg/m2 (10 mg/kg), during the time of the entire conditioning treatment.
Special populations
Renal impairment
Studies in renally impaired patients have not been conducted. As thiotepa and its metabolites are poorly excreted in the urine, dose modification is not recommended in patients with mild or moderate renal insufficiency. However, caution is recommended.
Hepatic impairment
Thiotepa has not been studied in patients with hepatic impairment. Since thiotepa is mainly metabolized through the liver, caution needs to be exercised when thiotepa is used in patients with pre-existing impairment of liver function, especially in those with severe hepatic impairment. Dose modification is not recommended for transient alterations of hepatic parameters.
Elderly
The administration of thiotepa has not been specifically investigated in elderly patients. However, in clinical studies, a proportion of patients over the age of 65 received the same cumulative dose as the other patients. No dose adjustment was deemed necessary.
Method of administration
Thiophosphamide must be administered by a qualified healthcare professional as a 2-4 hours intravenous infusion via a central venous catheter.
Each Thiophosphamide vial must be reconstituted with 10 ml of sterile water for injection.
Precautions to be taken before handling or administering the medicinal product
Topical reactions associated with accidental exposure to thiotepa may occur. Therefore, the use of gloves is recommended in preparing the solution for infusion. If thiotepa solution accidentally contacts the skin, the skin must be immediately thoroughly washed with soap and water. If thiotepa accidentally contacts mucous membranes, they must be flushed thoroughly with water.
Hypersensitivity to the active substance.
Pregnancy and lactation.
Concomitant use with yellow fever vaccine and with live virus and bacterial vaccines.
The consequence of treatment with thiotepa at the recommended dose and schedule is profound myelosuppression, occurring in all patients. Severe granulocytopenia, thrombocytopenia, anaemia or any combination thereof may develop. Frequent complete blood counts, including differential white blood cell counts, and platelet counts need to be performed during the treatment and until recovery is achieved. Platelet and red blood cell support, as well as the use of growth factors such as Granulocyte-colony stimulating factor (G-CSF), should be employed as medically indicated. Daily white blood cell counts and platelet counts are recommended during therapy with thiotepa and after transplant for at least 30 days.
Prophylactic or empiric use of anti-infectives (bacterial, fungal, viral) should be considered for the prevention and management of infections during the neutropenic period.
Thiotepa has not been studied in patients with hepatic impairment. Since thiotepa is mainly metabolized through the liver, caution needs to be observed when thiotepa is used in patients with pre-existing impairment of liver function, especially in those with severe hepatic impairment. When treating such patients it is recommended that serum transaminase, alkaline phosphatase and bilirubin are monitored regularly following transplant, for early detection of hepatotoxicity.
Patients who have received prior radiation therapy, greater than or equal to three cycles of chemotherapy, or prior progenitor cell transplant may be at an increased risk of hepatic veno-occlusive disease.
Caution must be used in patients with history of cardiac diseases, and cardiac function must be monitored regularly in patients receiving thiotepa.
Caution must be used in patients with history of renal diseases and periodic monitoring of renal function should be considered during therapy with thiotepa.
Thiotepa might induce pulmonary toxicity that may be additive to the effects produced by other cytotoxic agents (busulfan, fludarabine and cyclophosphamide).
Previous brain irradiation or craniospinal irradiation may contribute to severe toxic reactions (e.g. encephalopathy).
The increased risk of a secondary malignancy with thiotepa, a known carcinogen in humans, must be explained to the patient.
Concomitant use with live attenuated vaccines (except yellow fever vaccines), phenytoin and fosphenytoin is not recommended.
Thiotepa must not be concurrently administered with cyclophosphamide when both medicinal products are present in the same conditioning treatment. Thiophosphamide must be delivered after the completion of any cyclophosphamide infusion.
During the concomitant use of thiotepa and inhibitors of CYP2B6 or CYP3A4, patients should be carefully monitored clinically.
As most alkylating agents, thiotepa might impair male or female fertility. Male patients should seek for sperm cryopreservation before therapy is started and should not father a child while treated and during the year after cessation of treatment.
Thiophosphamide may have major influence on the ability to drive and use machines. It is likely that certain adverse reactions of thiotepa like dizziness, headache and blurred vision could affect these functions.
Summary of the safety profile
The safety of thiotepa has been examined through a review of adverse events reported in published data from clinical trials. In these studies, a total of 6,588 adult patients and 902 paediatric patients received thiotepa for conditioning treatment prior to haematopoietic progenitor cell transplantation.
Serious toxicities involving the haematologic, hepatic and respiratory systems were considered as expected consequences of the conditioning regimen and transplant process. These include infection and Graft-versus host disease (GvHD) which, although not directly related, were the major causes of morbidity and mortality, especially in allogeneic HPCT.
The most frequently adverse reactions reported in the different conditioning treatments including thiotepa are: infections, cytopenia, acute GvHD and chronic GvHD, gastrointestinal disorders, haemorrhagic cystitis, mucosal inflammation.
Leukoencephalopathy
Cases of leukoencephalopathy have been observed following treatment with thiotepa in adult and paediatric patients with multiple previous chemotherapies, including methotrexate and radiotherapy. Some cases had a fatal outcome.
Tabulated list of adverse reactions
Adults
The adverse reactions considered at least possibly related to conditioning treatment including thiotepa, reported in adult patients as more than an isolated case, are listed below by system organ class and by frequency. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. Frequencies are defined as: very common (>1/10), common ((>1/100 to <1/10), uncommon (>1/1,000 to <1/100), rare (>1/10,000 to <1/1,000) very rare (<1/10,000), not known (cannot be estimated from the available data).
| System organ class | Very common | Common | Uncommon | Not known |
| Infections and infestations | Infection susceptibility increased Sepsis | Toxic shock syndrome | ||
| Neoplasms benign, malignant and unspecified (incl cysts and polyps) | Treatment related second malignancy | |||
| Blood and lymphatic system disorders | Leukopenia Thrombocytopenia Febrile neutropenia Anaemia Pancytopenia Granulocytopenia | |||
| Immune system disorders | Acute graft versus host disease Chronic graft versus host disease | Hypersensitivity | ||
| Endocrine disorders | Hypopituitarism | |||
| Metabolism and nutrition disorders | Anorexia Decreased appetite Hyperglycaemia | |||
| Psychiatric disorders | Confusional state Mental status changes | Anxiety | Delirium Nervousness Hallucination Agitation | |
| Nervous system disorders | Dizziness Headache Vision blurred Encephalopathy Convulsion Paraesthesia | Intracranial aneurysm Extrapyramidal disorder Cognitive disorder Cerebral haemorrhage | Leukoencephalopathy | |
| Eye disorders | Conjunctivitis | Cataract | ||
| Ear and labyrinth disorders | Hearing impaired Ototoxicity Tinnitus | |||
| Cardiac disorders | Arrhythmia | Tachycardia Cardiac failure | Cardiomyopathy Myocarditis | |
| Vascular disorders | Lymphoedema Hypertension | Haemorrhage Embolism | ||
| Respiratory, thoracic and mediastinal disorders | Idiopathic pneumonia syndrome Epistaxis | Pulmonary oedema Cough Pneumonitis | Hypoxia | |
| Gastrointestinal disorders | Nausea Stomatitis Oesophagitis Vomiting Diarrhoea Dyspepsia Abdominal pain Enteritis Colitis | Constipation Gastrointestinal perforation Ileus | Gastrointestinal ulcer | |
| Hepatobiliary disorders | Venoocclusive liver disease Hepatomegaly Jaundice | |||
| Skin and subcutaneous tissue disorders | Rash Pruritus Alopecia | Erythema | Pigmentation disorder Erythrodermic psoriasis | Severe toxic skin reactions including cases of Stevens-Johnson syndrome and toxic epidermal necrolysis |
| Musculoskeletal and connective tissue disorders | Back pain Myalgia Arthralgia | |||
| Renal and urinary disorders | Cystitis haemorrhagic | Dysuria Oliguria Renal failure Cystitis Haematuria | ||
| Reproductive system and breast disorders | Azoospermia Amenorrhoea Vaginal haemorrhage | Menopausal symptoms Infertility female Infertility male | ||
| General disorders and administration site conditions | Pyrexia Asthenia Chills Generalised oedema Injection site inflammation Injection site pain Mucosal inflammation | Multi-organ failure Pain | ||
| Investigation | Weight increased Blood bilirubin increased Transaminases increased Blood amylase increased | Blood creatinine increased Blood urea increased Gamma-glutamyltransferase increased Blood alkaline phosphatase increased Aspartate aminotransferase increased |
Paediatric population
The adverse reactions considered at least possibly related to conditioning treatment including thiotepa, reported in paediatric patients as more than an isolated case, are listed below by system organ class and by frequency. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. Frequencies are defined as: very common (>1/10), common ((>1/100 to <1/10), uncommon (>1/1,000 to <1/100), rare (>1/10,000 to <1/1,000) very rare (<1/10,000), not known (cannot be estimated from the available data).
| System organ class | Very common | Common | Not known |
| Infections and infestations | Infection susceptibility increased Sepsis | Thrombocytopenic purpura | |
| Neoplasms benign, malignant and unspecified (incl cysts and polyps) | Treatment related second malignancy | ||
| Blood and lymphatic system disorders | Thrombocytopenia Febrile neutropenia Anaemia Pancytopenia Granulocytopenia | ||
| Immune system disorders | Acute graft versus host disease Chronic graft versus host disease | ||
| Endocrine disorders | Hypopituitarism Hypogonadism Hypothyroidism | ||
| Metabolism and nutrition disorders | Anorexia Hyperglycaemia | ||
| Psychiatric disorders | Mental status changes | Mental disorder due to a general medical condition | |
| Nervous system disorders | Headache Encephalopathy Convulsion Cerebral haemorrhage Memory impairment Paresis | Ataxia | Leukoencephalopathy |
| Ear and labyrinth disorders | Hearing impaired | ||
| Cardiac disorders | Cardiac arrest | Cardiovascular insufficiency Cardiac failure | |
| Vascular disorders | Haemorrhage | Hypertension | |
| Respiratory, thoracic and mediastinal disorders | Pneumonitis | Idiopathic pneumonia syndrome Pulmunary haemorrage Pulmonary oedema Epistaxis Hypoxia Respiratory arrest | Pulmonary arterial hypertension |
| Gastrointestinal disorders | Nausea Stomatitis Vomiting Diarrhoea Abdominal pain | Enteritis Intestinal obstruction | |
| Hepatobiliary disorders | Venoocclusive liver disease | Liver failure | |
| Skin and subcutaneous tissue disorders | Rash Erythema Desquamation Pigmentation disorder | Severe toxic skin reactions including cases of Stevens-Johnson syndrome and toxic epidermal necrolysis | |
| Musculoskeletal and connective tissue disorders | Growth retardation | ||
| Renal and urinary disorders | Bladder disorders | Renal failure Cystitis haemorrhagic | |
| General disorders and administration site conditions | Pyrexia Mucosal inflammation Pain Multi-organ failure | ||
| Investigation | Blood bilirubin increased Transaminases increased Blood creatinine increased Aspartate aminotransferase increased Alanine aminotransferase increased | Blood urea increased Blood electrolytes abnormal Prothrombin time ratio increased |
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
Yellow Card Scheme
Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store
There is no experience with overdoses of thiotepa. The most important adverse reactions expected in case of overdose is myeloablation and pancytopenia.
There is no known antidote for thiotepa.
The haematological status needs to be closely monitored and vigorous supportive measures instituted as medically indicated.
Pharmacotherapeutic group: Antineoplastic agents, Alkylating Agents, ATC code: L01AC01
Mechanism of action
Thiotepa is a polyfunctional cytotoxic agent related chemically and pharmacologically to the nitrogen mustard. The radiomimetic action of thiotepa is believed to occur through the release of ethylene imine radicals that, as in the case of irradiation therapy, disrupt the bonds of DNA, e.g. by alkylation of guanine at the N-7, breaking the linkage between the purine base and the sugar and liberating alkylated guanine.
Clinical safety and efficacy
The conditioning treatment must provide cytoreduction and ideally disease eradication. Thiotepa has marrow ablation as its dose-limiting toxicity, allowing significant dose escalation with the infusion of autologous HPCT. In allogeneic HPCT, the conditioning treatment must be sufficiently immunosuppressive and myeloablative to overcome host rejection of the graft. Due to its highly myeloablative characteristics, thiotepa enhances recipient immunosuppression and myeloablation, thus strengthening engraftment; this compensates for the loss of the GvHD-related GvL effects. As alkylating agent, thiotepa produces the most profound inhibition of tumour cell growth in vitro with the smallest increase in medicinal product concentration. Due to its lack of extramedullary toxicity despite dose escalation beyond myelotoxic doses, thiotepa has been used for decades in combination with other chemotherapy medicinal products prior to autologous and allogeneic HPCT.
The results of published clinical studies supporting the efficacy of thiotepa are summarised:
Autologous HPCT
Haematological diseases
Engraftment: Conditioning treatments including thiotepa have proved to be myeloablative.
Disease Free Survival (DFS): An estimated 43% at five years has been reported, confirming that conditioning treatments containing thiotepa following autologous HPCT are effective therapeutic strategies for treating patients with haematological diseases.
Relapse: In all conditioning treatments containing thiotepa, relapse rates at more than 1 year have been reported as being 60% or lower, which was considered by the physicians as the threshold to prove efficacy. In some of the conditioning treatments evaluated, relapse rates lower than 60% have also been reported at 5 years.
Overall Survival (OS): OS ranged from 29% to 87% with a follow-up ranging from 22 up to 63 months.
Regimen Related Mortality (RRM) and Transplant Related Mortality TRM : RRM values ranging from 2.5% to 29% have been reported. TRM values ranged from 0% to 21% at 1 year, confirming the safety of the conditioning treatment including thiotepa for autologous HPCT in adult patients with haematological diseases.
Solid tumours
Engraftment: Conditioning treatments including thiotepa have proved to be myeloablative.
Disease Free Survival (DFS): Percentages reported with follow-up periods of more than 1 year confirm that conditioning treatments containing thiotepa following autologous HPCT are effective choices for treating patients with solid tumours.
Relapse: In all conditioning treatments containing thiotepa, relapse rates at more than 1 year have been reported as being lower than 60%, which was considered by the physicians as the threshold to prove efficacy. In some cases, relapse rates of 35% and of 45% have been reported at 5 years and 6 years respectively.
Overall Survival: OS ranged from 30% to 87% with a follow-up ranging from 11.7 up to 87 months.
Regimen Related Mortality (RRM) and Transplant Related Mortality (TRM): RRM values ranging from 0% to 2% have been reported. TRM values ranged from 0% to 7.4% confirming the safety of the conditioning treatment including thiotepa for autologous HPCT in adult patients with solid tumours.
Allogeneic HPCT
Haematological diseases
Engraftment: Engraftment has been achieved (92%-100%) in all reported conditioning treatments and it was considered to occur at the expected time. Therefore it can be concluded that conditioning treatments including thiotepa are myeloablative.
GvHD (graft versus host disease): all conditioning treatments evaluated assured a low incidence of acute GvHD grade III-IV (from 4% to 24%).
Disease Free Survival (DFS): Percentages reported with follow-up periods of more than 1 year and up to 5 years confirm that conditioning treatments containing thiotepa following allogeneic HPCT are effective choices for treating patients with haematological diseases.
Relapse: In all conditioning treatments containing thiotepa, relapse rates at more than 1 year have been reported as being lower than 40% (which was considered by the physicians as the threshold to prove efficacy). In some cases, relapse rates lower than 40% have also been reported at 5 years and 10 years.
Overall Survival: OS ranged from 31% to 81% with a follow-up ranging from 7.3 up to 120 months.
Regimen Related Mortality (RRM) and Transplant Related Mortality (TRM): low values have been reported, confirming the safety of the conditioning treatments including thiotepa for allogeneic HPCT in adult patients with haematological diseases.
Paediatric population
Autologous HPCT
Solid tumours
Engraftment: It has been achieved with all reported conditioning regimens including thiotepa.
Disease Free Survival (DFS): With a follow-up of 36 to 57 months, DFS ranged from 46% to 70% in the reported studies. Considering that all patients were treated for high risk solid tumours, DFS results confirm that conditioning treatments containing thiotepa following autologous HPCT are effective therapeutic strategies for treating paediatric patients with solid tumours.
Relapse: In all the reported conditioning regimens containing thiotepa, relapse rates at 12 to 57 months ranged from 33% to 57%. Considering that all patients suffer of recurrence or poor prognosis solid tumours, these rates support the efficacy of conditioning regimens based on thiotepa.
Overall Survival (OS): OS ranged from 17% to 84% with a follow-up ranging from 12.3 up to 99.6 months.
Regimen Related Mortality (RRM) and Transplant Related Mortality (TRM): RRM values ranging from 0% to 26.7% have been reported. TRM values ranged from 0% to 18% confirming the safety of the conditioning treatments including thiotepa for autologous HPCT in paediatric patients with solid tumours.
Allogeneic HPCT
Haematological diseases
Engraftment: It has been achieved with all evaluated conditioning regimens including thiotepa with a success rate of 96% - 100%. The haematological recovery is in the expected time.
Disease Free Survival (DFS): Percentages of 40% - 75% with follow-up of more than 1 year have been reported. DFS results confirm that conditioning treatment containing thiotepa following allogeneic HPCT are effective therapeutic strategies for treating paediatric patients with haematological diseases.
Relapse: In all the reported conditioning regimens containing thiotepa, the relapse rate was in the range of 15% - 44%. These data support the efficacy of conditioning regimens based on thiotepa in all haematological diseases.
Overall Survival (OS): OS ranged from 50% to 100% with a follow-up ranging from 9.4 up to 121 months.
Regimen Related Mortality (RRM) and Transplant Related Mortality (TRM): RRM values ranging from 0% to 2.5% have been reported. TRM values ranged from 0% to 30% confirming the safety of the conditioning treatment including thiotepa for allogeneic HPCT in paediatric patients with haematological diseases.
Absorption
Thiotepa is unreliably absorbed from the gastrointestinal tract: acid instability prevents thiotepa from being administered orally.
Distribution
Thiotepa is a highly lipophilic compound. After intravenous administration, plasma concentrations of the active substance fit a two compartment model with a rapid distribution phase. The volume of distribution of thiotepa is large and it has been reported as ranging from 40.8 l/m2 to 75 l/m2, indicating distribution to total body water. The apparent volume of distribution of thiotepa appears independent of the administered dose. The fraction unbound to proteins in plasma is 70-90%; insignificant binding of thiotepa to gamma globulin and minimal albumin binding (10-30%) has been reported.
After intravenous administration, CSF medicinal product exposure is nearly equivalent to that achieved in plasma; the mean ratio of AUC in CSF to plasma for thiotepa is 0.93. CSF and plasma concentrations of TEPA, the first reported active metabolite of thiotepa, exceed the concentrations of the parent compound.
Biotransformation
Thiotepa undergoes rapid and extensive hepatic metabolism and metabolites could be detected in urine within 1 hour after infusion. The metabolites are active alkylating agents but the role they play in the antitumor activity of thiotepa remains to be elucidated. Thiotepa undergoes oxidative desulphuration via the cytochrome P450 CYP2B and CYP3A isoenzyme families to the major and active metabolite TEPA (triethylenephosphoramide). The total excreted amount of thiotepa and its identified metabolites accounts for 54-100% of the total alkylating activity, indicating the presence of other alkylating metabolites. During conversion of GSH conjugates to N-acetylcysteine conjugates, GSH, cysteinylglycine, and cysteine conjugates are formed. These metabolites are not found in urine, and, if formed, are probably excreted in bile or as intermediate metabolites rapidly converted into thiotepa-mercapturate.
Elimination
The total clearance of thiotepa ranged from 11.4 to 23.2 l/h/m2. The elimination half-life varied from 1.5 to 4.1 hours. The identified metabolites TEPA, monochlorotepa and thiotepa-mercapturate are all excreted in the urine. Urinary excretion of thiotepa and TEPA is nearly complete after 6 and 8 hours respectively. The mean urinary recovery of thiotepa and its metabolites is 0.5% for the unchanged medicinal product and monochlorotepa, and 11% for TEPA and thiotepa-mercapturate.
Linearity /non linearity
There is no clear evidence of saturation of metabolic clearance mechanisms at high doses of thiotepa.
Special populations
Paediatric population
The pharmacokinetics of high dose thiotepa in children between 2 and 12 years of age do not appear to vary from those reported in children receiving 75 mg/m2 or adults receiving similar doses.
Renal impairment
The effects of renal impairment on thiotepa elimination have not been assessed.
Hepatic impairment
The effects of hepatic impairment on thiotepa metabolism and elimination have not been assessed.
No conventional acute and repeat dose toxicity studies were performed.
Thiotepa was shown to be genotoxic in vitro and in vivo, and carcinogenic in mice and rats.
Thiotepa was shown to impair fertility and interfere with spermatogenesis in male mice, and to impair ovarian function in female mice. It was teratogenic in mice and in rats, and foeto-lethal in rabbits. These effects were seen at doses lower than those used in humans.
Preparation of Thiophosphamide
Procedures for proper handling and disposal of anticancer medicinal products must be considered. All transfer procedures require strict adherence to aseptic techniques, preferably employing a vertical laminar flow safety hood.
As with other cytotoxic compounds, caution needs to be exercised in handling and preparation of Thiophosphamide solutions to avoid accidental contact with skin or mucous membranes. Topical reactions associated with accidental exposure to thiotepa may occur. In fact, the use of gloves is recommended in preparing the solution for infusion. If thiotepa solution accidentally contacts the skin, the skin must be immediately and thoroughly washed with soap and water. If thiotepa accidentally contacts mucous membranes, they must be flushed thoroughly with water.
Reconstitution
Thiophosphamide must be reconstituted with 10 ml of sterile water for injection.
Using a syringe fitted with a needle, aseptically withdraw 10 ml of sterile water for injection.
Inject the content of the syringe into the vial through the rubber stopper.
Remove the syringe and the needle and mix manually by repeated inversions.
Only colourless solutions, without any particulate matter, must be used. Reconstituted solutions may occasionally show opalescence; such solutions can still be administered.
Further dilution in the infusion bag
The reconstituted solution is hypotonic and must be further diluted prior to administration with 500 ml sodium chloride 9 mg/ml (0.9%) solution for injection (1000 ml if the dose is higher than 500 mg) or with an appropriate volume of sodium chloride 9 mg/ml (0.9%) in order to obtain a final Thiophosphamide concentration between 0.5 and 1 mg/ml.
Administration
Thiophosphamide infusion solution should be inspected visually for particulate matter prior to administration. Solutions containing a precipitate should be discarded.
Prior to and following each infusion, the indwelling catheter line should be flushed with approximately 5 ml sodium chloride 9 mg/ml (0.9%) solution for injection.
The infusion solution must be administered to patients using an infusion set equipped with a 0.2 µm in-line filter. Filtering does not alter solution potency.
Disposal
Thiophosphamide is for single use only.
Any unused product or waste material should be disposed of in accordance with local requirements.
