Genmab Announces Rinatabart Sesutecan (Rina-S®) Demonstrates Statistically Significant Improvement in Progression-Free Survival and Overall Survival in Patients with Platinum-Resistant Ovarian Cancer

• Phase 3 RAINFOL™-02 trial met its primary endpoint of progression-free survival (PFS) and its key secondary endpoint of overall survival (OS) with rinatabart sesutecan (Rina-S®) compared to investigator's choice chemotherapy

• Results demonstrated statistically significant and clinically meaningful improvement in PFS and OS in patients with platinum-resistant ovarian cancer (PROC)

• Data will be submitted for presentation at a future medical meeting and discussed with regulatory authorities worldwide

COPENHAGEN, Denmark, October 23, 2026--Genmab A/S (Nasdaq: GMAB) announced today 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.

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."