GSK's Mo-Rez Posts 62% Response Rate in Platinum-Resistant Ovarian Cancer
GSK sits 19% above its 52-week low of $42.845.
Summary
GSK reported updated phase Ib data showing Mo-Rez produced a 62% confirmed response rate and 11.1-month median progression-free survival in platinum-resistant ovarian cancer, with five phase III trials now running across gynaecological cancers.
Key Events · Product Development and Regulatory · GSK
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Mo-Rez Hits 62% Response Rate
In the phase Ib BEHOLD-1 trial at the 5.8 mg/kg phase III dose, Mo-Rez achieved a confirmed objective response rate of 62% (n=28/45) with a 12.2-month median duration of response.
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Progression-Free Survival of 11.1 Months
Median PFS was 11.1 months (95% CI: 8.3-13.9) in platinum-resistant ovarian cancer, a setting where durable disease control is typically difficult to achieve.
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Five Phase III Trials Underway
Pivotal studies now span platinum-resistant ovarian, platinum-sensitive ovarian, first-line ovarian maintenance, second-line endometrial and first-line endometrial maintenance settings.
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Safety Profile Mostly Haematologic
Grade 3 or higher treatment-related adverse events occurred in 71% (n=32/45) of patients; 47% required dose reductions and 2% (n=1/45) discontinued, with ILD/pneumonitis in 2%.
Analysis · GSK · Life Sciences
Mo-Rez is one of GSK's lead antibody-drug conjugate bets, and a 62% confirmed response rate with 12.2 months of durability in platinum-resistant ovarian cancer is well above what this hard-to-treat setting typically delivers. GSK has already committed to five pivotal phase III trials across ovarian and endometrial cancer, so the readout de-risks a programme that could become a multi-indication oncology franchise. The offset is safety: 71% of patients had Grade 3 or worse treatment-related events, mostly haematologic, with 47% needing dose reductions — tolerability will decide how broadly the drug can be used. For a company of GSK's size this moves the oncology pipeline narrative rather than the near-term earnings base.
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