Genmab has reported data from Part C of the Phase I/II RAINFOL-01 trial of rinatabart sesutecan (Rina-S; GEN1184) in patients with platinum-resistant ovarian cancer.
Rina-S is an investigational antibody-drug conjugate (ADC) comprising a human monoclonal antibody targeting folate receptor alpha (FRα), a hydrophilic protease-cleavable linker, and an exatecan topoisomerase I inhibitor payload.
The study evaluated 109 patients diagnosed with platinum-resistant ovarian cancer who received Rina-S.
It found a confirmed objective response rate of 45.9%, including five complete responses.
The median duration of response reached 12.1 months, with 51% of responders remaining in response after one year. Median progression-free survival was recorded at 9.5 months.
Antitumour activity was observed across all levels of FRα expression and regardless of prior mirvetuximab treatment.
Part C of the trial assessed Rina-S (120mg/m², once every three weeks) as a standalone treatment in patients with platinum-resistant high-grade serous ovarian, primary peritoneal, or fallopian tube cancer.
Eligible participants had previously received between one and three lines of therapy, except for those whose last treatment was mirvetuximab, who could have had up to four prior lines. More than half, or 53%, had either three or four previous lines of treatment.
All patients in the cohort had been treated with both bevacizumab and a taxane, while 49.5% had previously received a PARP inhibitor, and 33% had been administered mirvetuximab soravtansine. The median follow-up period exceeded one year.
Genmab executive vice-president and chief medical officer, experimental medicines head Tahamtan Ahmadi said: “These findings, including the observed antitumor activity, duration of response, and the first progression-free survival data reported for the programme, as well as the manageable tolerability, reinforce the potential of Rina-S.
“As our Phase III programme continues to advance, the results further inform our evaluation of Rina-S as a potential treatment option for patients with gynaecologic cancers.”
Common adverse events included fatigue and Grade 1 to 2 gastrointestinal symptoms such as vomiting, nausea, decreased appetite, constipation, and abdominal pain. Frequent haematologic events included neutropenia, anaemia, decreased platelet count, and thrombocytopenia.
Serious adverse events occurred in roughly one-third of participants, while 5.5% discontinued treatment due to adverse events. No safety signals were observed for interstitial lung disease, ocular toxicity, peripheral neuropathy, or stomatitis.
In June 2026, Genmab’s Phase III trial of a combination therapy including its bispecific T-cell engager (BiTE) combination, including Epkinly, met its primary endpoint in adult patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL).
