Abstract 545P
Background
Until now, patients with platinum-resistant ovarian cancer have a poor prognosis with limited response to second-line single agent chemotherapy. Reported response rates are poor and encompasses 13-20%. Insufficient treatment efficacy reflects short survival. There is a need to investigate new combined chemotherapy regimens. The mechanism of action and the distinct toxicity profile of each agent are relevant variables in new regimen design . The appropriate pharmacological and toxicological properties of irinotecan and treosulfan allow us to evaluate the efficiency and safety of their combination.
Methods
During the period of 2016-2020 we recruited 152 patients diagnosed with tubo-ovarian cancer or primary peritoneal carcinomatosis. The dosing regimen contained: Treosulfan administered every 3 weeks at 6 g /m2 dose , and irinotecan dosed 180 mg/m2 every 3 weeks. Both drugs were administered intravenously on day 1 of each treatment cycle. The total number of cycles not exceeded 6. Enrolled patients proceeded with at least 1 line of platinum-based chemotherapy and had a documented progressive disease in 6 month after treatment completion.The primary end-points were progression-free survival and objective response, secondary end-point was overall survival.
Results
A total of 791 cycles were conducted. 70% of patients completed all planned 6 cycles of treatement. Response assessment was performed according to RECIST 1.1 criteria . Complete responses were registered in 11 patients (7.2%), a partial response – in 56 patients (36.8%), and stable disease was documaneted in 41 patients (27.0%). Median time to progression was 6.63 months, median overall survival – 16.9 months. Adverse events were classified based on CTCAE 3.0/4.0. The most common non-hematological adverse event was diarrhea (7.8%). Grade 3-4 neutropenia was observed in 7,8%, grade 3-4 anemia - 1.9%, grade 3-4 thrombocytopenia - 0.5%.
Conclusions
Treosulfan–irinotecan combination demonstrates synergistic effect and has an acceptable toxicity profile.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
N.N. Alexandrov national cancer centre academic group.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.