• Treatment with rinatabart sesutecan (Rina-S) showed encouraging response rate in heavily pretreated patients with ovarian cancer in dose expansion cohort
• Responses with Rina-S were observed across FRα expression levels
• Phase 3 trial will further evaluate the safety and efficacy of Rina-S at 120 mg/m² in patients with advanced ovarian cancer
  
  

Genmab A/S (Nasdaq: GMAB) announced new data from the Phase 1/2 study of rinatabart sesutecan (Rina-S), an investigational folate receptor-alpha (FRα)-targeted, Topo1 antibody-drug conjugate (ADC), demonstrated a confirmed objective response rate (ORR) of 50.0% (95% CI) in ovarian cancer patients treated with Rina-S 120 mg/m² once every 3 weeks (Q3W), regardless of FRα 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 (OC) and endometrial cancer (EC). These results, and additional findings from the study, were presented at the European Society of Medical Oncology Congress 2024 (ESMO) in Barcelona, Spain.

Part B of the study randomized 42 previously-treated patients with histologically or cytologically confirmed advanced OC (epithelial ovarian cancer, primary peritoneal cancer or fallopian tube cancer) to Rina-S 100 mg/m² (n=22) or Rina-S 120 mg/m² (n=20). Ninety-five percent of patients in the 120 mg/m² group were identified as platinum-resistant ovarian cancer (PROC) 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 (0%) and 1 (5.6%); partial response in 4 (18.2%) and 8 patients (44.4%); stable disease in 15 (68.2%) and 7 patients (38.9%); disease progression in 3 patients (13.6%) and 1 patient (5.6%). 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 (DCR) was 86.4% and 88.9% (95% CI: 65.3-98.6), 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.

"Ovarian cancer presents a significant challenge, especially for those with advanced or recurrent cases, where treatment options and prognosis are often limited," said Elizabeth Lee, MD, a medical oncologist in the gynecologic oncology program at Dana-Farber. "The encouraging Phase 1/2 data for Rina-S demonstrates the potential for future treatment options for patients. We are looking forward to additional data from tumor-specific dose expansion cohorts.”

In this Phase 1/2 study, common treatment-emergent adverse events (TEAEs) 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 (ILD) were observed.

“We are encouraged by the data from this ongoing Phase 1/2 trial evaluating Rina-S in a patient population that is in need of new therapeutic options and believe the data support the potential for Rina-S to demonstrate anti-tumor activity beyond first-generation folate receptor-alpha based therapies,” said Jan van de Winkel, Ph.D., President and Chief Executive Officer of Genmab. “Genmab is pioneering technologies that aim to transform the treatment of cancer and other serious diseases. We are committed to evaluating the full potential utility of Rina-S in patients with ovarian, endometrial and other solid tumor cancers.”