Cyteir Therapeutics, Inc. (?Cyteir?) presented ongoing results from a dose expansion cohort in its Phase 1 combination study of CYT-0851 with capecitabine in patients with platinum-refractory or -resistant ovarian cancer in a late-breaker poster titled ?Phase 1 Dose Expansion Results of CYT-0851, a Monocarboxylate Transporter (MCT) Inhibitor, in Combination with Capecitabine in Platinum-Resistant Ovarian Cancer? (Poster: LB_A13) at the 2023 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics meeting in Boston, Massachusetts. The primary objective of the expansion cohort of the ongoing Phase 1 combination study is to determine in advanced platinum-resistant ovarian cancer patients the safety and tolerability of the CYT-0851 plus capecitabine combination.

Other secondary objectives included the determination of pharmacokinetic parameters and to characterize the preliminary anti-tumor activity. The poster presents ongoing results for eleven evaluable patients with platinum-refractory or -resistant ovarian cancer treated in this expansion cohort. As of the September 26, 2023 data cutoff, 11 patients with advanced ovarian cancer were treated and evaluable in the capecitabine cohort.

Patients were heavily pretreated, with a median of six prior treatment regimens; four patients were platinum-refractory, and seven patients were platinum-resistant. Ten patients were treated with CYT-0851 at the recommended Phase 2 dose of 400 mg daily, and one patient was treated with CYT-0851 at 300 mg daily. Two patients had a confirmed partial response by RECIST and one additional patient achieved an unconfirmed partial response.

Seven patients had stable disease and one patient had progressive disease. The disease control rate was 91% and median progression-free survival was 170 days. To date, CYT-0851 has exhibited a generally well tolerated safety profile with no unanticipated toxicities observed at clinically active doses.

The median treatment compliance was 99%. There were no treatment discontinuations or dose reductions for treatment related adverse events. All treatment related adverse events were mild (Grade 1-2).

The most common adverse events were fatigue (46%) and decreased appetite, diarrhea, nausea, palmar-plantar erythrodysesthesia syndrome and vomiting (18%).