Genmab has linked an antibody-drug conjugate (ADC) to median progression-free survival (PFS) of 9.5 months, leading TD Cowen analysts to hail the asset as “clearly superior” to AbbVie’s Elahere.
Like Elahere, Genmab’s rinatabart sesutecan (Rina-S) is an FRα-directed ADC. Part C of Genmab’s phase 1/2 Rainfol-01 trial tested Rina-S in 109 patients with platinum-resistant ovarian cancer (PROC). Genmab reported an objective response rate (ORR) of 55.6% in ovarian cancer patients in an earlier part of the trial.
ORR was lower in part C, clocking in at 45.9%. Yet, while noting that ORR “moderated” in the new data, TD Cowen analysts hailed the readout as a boost for Genmab in a note to investors titled “Rina-S Makes It RAIN.”
Rina-S “ought to overtake” Elahere given its differentiated efficacy and safety and is ahead of the pack of next-generation FRα-directed ADCs, the analysts argued.
Calling the efficacy results “solid,” the analysts focused on cross-trial survival comparisons. Median PFS of 9.5 months for Rina-S is “meaningfully better than Elahere’s 5.6 months,” they said, quoting data from a phase 3 trial that compared AbbVie’s ADC to chemotherapy in 453 patients.
The Rina-S result “establishes strong durability in a broad, heavily pretreated population,” the analysts continued. In Genmab’s study, 53% of patients had received three or four prior lines of therapy. All patients had received prior bevacizumab and taxane therapy. Almost half of patients had tried a PARP inhibitor and one-third had received Elahere.
Genmab reported antitumor activity regardless of prior treatment with Elahere. Similarly, Genmab saw activity in patients with low FRα expression and non-expressors. Elahere is indicated for use in FRα-positive PROC.
The data were positive when it came to adverse events. Elahere has (PDF) a boxed warning for ocular toxicity and AbbVie's drug has been associated with Grade 3 ocular adverse reactions in 11% of patients. In contrast, Genmab's latest data revealed no safety signals for ocular toxicity or peripheral neuropathy, interstitial lung disease or stomatitis.
AbbVie has reported grade 4 cases of keratopathy and cataract, while fatigue, nausea and vomiting were more common on Rina-S than Elahere.
TD Cowen analysts said Genmab’s data provide a “clear readthrough” for the phase 3 Rainfol-02 trial, which is comparing Rina-S to the investigator’s choice of treatment in PROC. The primary endpoint of that study is PFS and Genmab expects (PDF) to share some data this year.
The biopharma predicts that the trial, plus studies in endometrial cancer and in platinum-sensitive ovarian cancer (PSOC), can drive Rina-S sales north of $2 billion. Elahere, which is not used in endometrial cancer or PSOC, generated $690 million in 2025, its third full year on the market. Part C data “reinforce our confidence that Rina-S will outpace this trajectory as the clearly superior drug,” the analysts said.
AbbVie is defending its business in the courts. Last year, AbbVie accused Genmab of being “willfully blind” to the theft of trade secrets when buying Rina-S in its $1.8 billion ProfoundBio takeover. Genmab provided (PDF) an update on the allegations, which it refutes, in its second-quarter earnings.
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