Ifosfamide

Additional information

Worse outcome has been demonstrated in young male adults, compared to females, with Ewing sarcoma [1].

Pharmacokinetics and dosing

Studies have not been able to verify sex-related discrepancy in pharmacokinetics of ifosfamide [2].

Effects

Ifosfamide and cyclophosphamide were compared as single drugs in a randomized phase II study including 135 patients (15-70 years old) with advanced or metastatic soft-tissue sarcoma. Overall response rates considering both treatments together were four times higher in girls/women (20% vs. 5%). Sex difference was not significant taking ifosfamide alone (9 of 40 (23%) for girls/women vs 3 of 38 (8%) for boys/men) [3].

In a meta-analysis of three randomized clinical trials on sarcoma (897 boys/men and 631 girls/women, median age 12 (range 0-50) years), patients were treated with either cyclophosphamide or ifosfamide in combination with vincristine and dactinomycin. Analyses showed no significant heterogeneity of the treatment effect between sexes for both agents together [4].

Adverse effects

Subgroup analysis of data from a randomized noninferiority study (EE99-R1) [5] comparing cyclophosphamide with ifosfamide, revealed higher risk of ifosfamide toxicity in girls/women than in boys/men (251 boys/men, 174 girls/women, median age 14 (range 0-50) years). The most significant sex-related differences were observed for nephrotoxicity (OR 2.98, 95% CI 1.43-6.2), infection (OR 2.5, 95% CI 1.68-3.73) and leukopenia/neutropenia (OR 1.58, 95% CI 1.01-2.47) [5]. Two smaller clinical studies conducted earlier showed no significant different toxicity of ifosfamide between boys/men and girls/women [6, 7]. A meta-analysis in pediatric and adult sarcoma patients mentioned above [4] came to comparable conclusions as of the EE99-R1 study [5].

Sex-related difference in chemotherapy toxicity was evaluated in patients with non-metastatic osteosarcoma. Among those treated with regimens including ifosfamide, doxorubicin and cisplatin (501 boys/men, 255 girls/women, median age 17 (4-40) years), female patients experienced hematological toxicities more frequently than males. The frequency of grade four neutropenia and thrombocytopenia were significantly higher in the females than males (65 vs 50 %, and 51 vs 25 %) [8].

Reproductive health issues

Fetal defects and miscarriages have been reported. Women of childbearing potential and their partner should be advised against becoming pregnant and advised to use effective contraception during and 6 months after treatment with ifosfamide [9]. Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).