On October 23, 2026 Genmab A/S (Nasdaq: GMAB) reported positive topline results from the global Phase 3 RAINFOL-02 trial of rinatabart sesutecan (Rina-S), an investigational folate receptor alpha (FRα)-targeted, topoisomerase I (TOPO1)-inhibitor antibody-drug conjugate (ADC), in patients with platinum-resistant ovarian cancer (PROC) regardless of FRα expression level or prior treatment with mirvetuximab. The trial met its primary endpoint of progression-free survival (PFS), with Rina-S demonstrating a statistically significant and clinically meaningful improvement compared with investigator’s choice chemotherapy in the intent-to-treat (ITT) and in the primary analysis set (PAS) populations.

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The ITT population (N=584) comprised of all randomized patients with PROC, regardless of FRα expression. The PAS population (N=492) mandated patients with FRα expression ≥75% PS2+ to have been treated with mirvetuximab.

In the ITT population, Rina-S demonstrated a 71% reduction in the risk of disease progression or death (HR 0.29; 95% CI, 0.23-0.37; p<0.0001). In the PAS population, Rina-S demonstrated a 67% reduction in the risk of disease progression or death (HR 0.33; 95% CI, 0.26–0.42; p<0.0001).

The study also met its key secondary endpoint of overall survival (OS), demonstrating a statically significant and clinically meaningful improvement in the ITT population (HR 0.43; 95% CI, 0.31–0.59; p<0.0001) and in the PAS population (HR 0.44; 95% CI, 0.31–0.63; p<0.0001).

The observed safety profile was consistent with the known profile of Rina-S, with no new safety signals or unexpected safety concerns identified.

"As the first Phase 3 readout from our Rina-S program, the positive topline results from RAINFOL-02 mark a significant milestone for Genmab and strengthen our confidence in Rina-S’s potential for patients with platinum-resistant ovarian cancer. These results advance our ambition to become a leader in gynecologic oncology and reflect our commitment to improving the lives of patients with high unmet medical needs," said Jan van de Winkel, Ph.D., Chief Executive Officer of Genmab. "We look forward to discussing these results and potential next steps with regulatory authorities worldwide. We are deeply grateful to the patients, caregivers, and investigators whose participation made this study possible."

Based on these results, Genmab plans to engage with regulatory authorities worldwide regarding potential next steps. The data will also be submitted for presentation at a future medical meeting.

"Platinum-resistant ovarian cancer remains one of the greatest challenges in gynecologic oncology, with patients often facing a poor prognosis and limited effective treatment options. The Phase 3 RAINFOL-02 results set a new benchmark in addressing this urgent unmet need regardless of FRα expression," said Angeles Alvarez Secord, MD, MHSc, the study’s lead investigator for the Gynecologic Oncology Group (GOG) and Professor of Obstetrics and Gynecology at the Duke Cancer Institute. "The 71% reduction in the risk of disease progression and 57% reduction in the risk of death underscore the potential of Rina-S to change clinical practice if approved by offering a therapeutic option for a broad patient population."

Rina-S is being evaluated in a broad clinical development program spanning multiple gynecologic cancers and other solid tumors. The program includes five Phase 3 trials evaluating Rina-S in PROC (RAINFOL-02; NCT06619236), recurrent or progressive endometrial cancer (RAINFOL-03; NCT07166094), platinum-sensitive ovarian cancer (PSOC) maintenance therapy (RAINFOL-04; NCT07225270), second-line PSOC (RAINFOL-07; NCT07564141), and in first-line ovarian cancer as maintenance therapy (RAINFOL-10; NCT07859215). Additional studies include the Phase 1/2 RAINFOL-01 trial (NCT05579366) and Phase 2 trials in non-small cell lung cancer (RAINFOL-05; NCT07288177) and advanced gastrointestinal cancers (RAINFOL-09; NCT07539311).

On Wednesday, October 28 at 5:00 p.m. CET/12:00 p.m. EDT, Genmab will host an investor update. To register, visit genmab.com/events-presentations.

About the RAINFOL-02 Trial RAINFOL-02 (NCT06619236) is a randomized, open-label, multicenter Phase 3 study evaluating the efficacy and safety of Rina-S versus investigator’s choice chemotherapy in 582 patients with PROC regardless of FRα expression level. Patients are randomized 1:1 to receive either Rina-S 120 mg/m² on Day 1 of each three-week treatment cycle or one of four standard-of-care chemotherapy agents: paclitaxel, topotecan, PLD, or gemcitabine. The primary endpoint is investigator-assessed PFS. Key secondary endpoints are OS and objective response rate (ORR). Other secondary endpoints include PFS by blinded independent central review, duration of response, incidence of adverse events and laboratory abnormalities, time from randomization to second disease progression or death, and change from baseline in global health status/quality of life. Efficacy is evaluated in two populations. The ITT population (N = 584) includes all randomized patients, regardless of FRα expression level. The PAS (N=492), a subset of the ITT population, includes only patients with FRα expression <75% PS2+ and patients previously treated with mirvetuximab if eligible based on FRα expression ≥75% PS2+ and available in the region.

About Ovarian Cancer Ovarian cancer (OC) is a major global health issue, more than 320,000 new cases diagnosed annually worldwide.[i] It ranks as the eighth most common cancer and the eighth leading cause of cancer-related deaths among women globally.[ii] The disease is often diagnosed at an advanced stage because its symptoms, including abdominal bloating, pelvic pain and difficulty eating, can be subtle and nonspecific.[iii] Approximately 70-90% of women with advanced-stage OC worldwide experience a recurrence after initial treatment.[iv] OC has a ow five-year survival rate, which varies significantly by region, but generally hovers around 30-50%.[v],[vi]

About Rinatabart Sesutecan (Rina-S; GEN1184)
Rina-S (GEN1184) is an investigational ADC. It is composed of a novel human monoclonal antibody directed at FRα, a hydrophilic protease-cleavable linker, and exatecan, a TOPO1 inhibitor payload. The clinical trial program for Rina-S continues to expand, including ovarian, endometrial, and other cancers with unmet need.

The safety and efficacy of Rina-S have not been established. Please visit View Source for more information.

(Press release, Genmab, OCT 23, 2026, View Source [SID1234673707])