The combination of irinotecan and temozolomide is active and well tolerated in patients with relapsed Ewing sarcoma, according to a pooled analysis published in BMC Cancer

The researchers noted that prospective trials of irinotecan plus temozolomide have produced conflicting results. To gain insight into the benefits and risks of the combination, researchers conducted a pooled analysis of 6 retrospective studies.

The cohort encompassed 184 patients with relapsed Ewing sarcoma, including those with recurrent disease and primary refractory disease. The median age of the patients ranged from 14 years to 21 years.

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All patients were treated with upfront or adjuvant irinotecan plus temozolomide. Irinotecan was given at 10-20 mg/m2 per day on days 1-5 and days 8-12, 10 mg/m2 per day on days 1-5 (or days 1-10), or 40 mg/m2 per day on days 1-5. Temozolomide was given at 100 mg/m2 per day on days 1-5. The median number of cycles ranged from 4 to 14.

In the pooled population, the objective response rate was 44%, and the disease control rate was 66%. The median progression-free survival (PFS) ranged from 3.8 months to 8.3 months, and the 1-year PFS rate was 44.4%. The median overall survival (OS) ranged from 12 months to 14.1 months, and the 1-year OS rate was 55%.

Treatment-related adverse events were analyzed based on the number of patients and the number of chemotherapy cycles. In 2 studies encompassing 104 patients, the rate of grade 3-4 neutropenia was 18%, and the rate of grade 3-4 thrombocytopenia was 6%.

In 3 studies encompassing 338 chemotherapy cycles, the pooled incidences of grade 3-4 neutropenia, thrombocytopenia, and diarrhea were 8%, 7%, and 8%, respectively.

“Irinotecan combined with temozolomide is an effective and safe chemotherapeutic strategy for patients with relapsed Ewing sarcoma,” the researchers concluded. “More future prospective studies are needed to confirm the retrospective results.”


Wang B-C, Xiao B-Y, and Lin G-H. Irinotecan plus temozolomide in relapsed Ewing sarcoma: An integrated analysis of retrospective studies. BMC Cancer. Published online March 31, 2022. doi:10.1186/s12885-022-09469-5