In a Phase II clinical trial published in the Journal of Clinical Oncology, Camptosar® (irinotecan) reduced or eliminated detectable cancer in 11% of children with relapsed or refractory rhabdomyosarcoma.
Rhabdomyosarcoma arises from skeletal muscle and is the most common soft tissue sarcoma in children. Approximately 20% of patients are diagnosed with disease that has already spread and have a poor prognosis with current combined therapies. The remaining 80% of patients are diagnosed with localized disease and have cure rates that range from 50–90%.
Patients with recurrent rhabdomyosarcoma have a very poor prognosis and are usually treated with chemotherapy. Active agents for the treatment of recurrent or refractory rhabdomyosarcoma include Cytoxan® (cyclophosphamide), Ifex® (ifosfamide), Adriamycin® (doxorubicin), Actinomycin D® (dactinomycin), Vepesid® (etoposide), Platinol® (cisplatin), and Paraplatin® (carboplatin).
To explore the safety and effectiveness of Camptosar® (irinotecan) in the treatment of relapsed or refractory rhabdomyosarcoma, researchers in France and the UK conducted a Phase II clinical trial among 35 patients under the age of 20 years. All patients had previously been treated with chemotherapy, 74% had been treated with radiation therapy, and 60% had been treated with surgery.
Study participants received intravenous Camptosar every three weeks.
- 11% of patients (four out of 35) had a partial or complete disappearance of detectable cancer following treatment.
- The median time to cancer progression (the time by which half the patients had experienced cancer progression) was 1.4 months. Median survival was 5.8 months.
- Neutropenia (low white blood cell level) was the most common serious side effect.
The researchers conclude that among heavily pretreated children with relapsed or refractory rhabdomyosarcoma, Camptosar reduced or eliminated detectable disease in 11% of patients and was reasonably well tolerated. The researchers note that Camptosar warrants additional evaluation in combination with other anticancer medications.
Reference: Vassal G, Couanet D, Stockdale E et al. Phase II trial of irinotecan in children with relapsed or refractory rhabdomyosarcoma: a joint study of the French society of pediatric oncology and the United Kingdom Children’s Cancer Study Group. Journal of Clinical Oncology 2007;25:356-361.