Genmab announces new data from Phase 1/2 study of Rina-S

Genmab announced new data from the Phase 1/2 study of rinatabart sesutecan, or Rina-S, an investigational folate receptor-alpha-targeted, Topo1 antibody-drug conjugate, demonstrated a confirmed objective response rate of 50.0% in ovarian cancer patients treated with Rina-S 120 mg/m2 once every 3 weeks, regardless of FRalpha expression levels. These data were from the dose expansion part of a multi-part study evaluating the safety and efficacy of single-agent Rina-S in ovarian cancer and endometrial cancer. These results, and additional findings from the study, were presented at the European Society of Medical Oncology Congress 2024 in Barcelona, Spain. Part B of the study randomized 42 previously-treated patients with histologically or cytologically confirmed advanced OC to Rina-S 100 mg/m2 or Rina-S 120 mg/m2. Ninety-five percent of patients in the 120 mg/m2 group were identified as platinum-resistant ovarian cancer as were 90.9% of patients in the 100 mg/m2 group. In patients receiving Rina-S 100 mg/m2, results showed a confirmed ORR of 18.2% compared with 50.0% among patients receiving 120 mg/m2. Results for 100 mg/m2 and 120 mg/m2 respectively also included: complete response: 0 and 1; partial response in 4 and 8 patients ; stable disease in 15 and 7 patients; disease progression in 3 patients and 1 patient. Only one patient in the 120 mg/m2 treatment arm was not evaluable. With a median on study follow-up of 24 weeks, all confirmed responses with the 120 mg/m2 dose were ongoing at the time of data cutoff. The disease control rate was 86.4% and 88.9%, respectively. Based on these results, Rina-S 120 mg/m2 has been selected for further evaluation in a Phase 3 trial for patients with advanced ovarian cancer, which is expected to start in 2024. In this Phase 1/2 study, common treatment-emergent adverse events included anemia, neutropenia, nausea, thrombocytopenia, leukopenia, fatigue, vomiting, alopecia, and diarrhea. Dose reductions and treatment discontinuations were infrequent. No signals of ocular toxicities, neuropathy or interstitial lung disease were observed.