GSK (LSE:GSK) reported updated phase Ib data on Monday showing mocertatug rezetecan (Mo-Rez) produced a 62% confirmed objective response rate in platinum-resistant ovarian cancer, with responses lasting a median of 12.2 months at more than 13 months of follow-up.
The London-listed pharmaceutical group's antibody-drug conjugate, which targets the B7-H4 checkpoint protein, achieved the response rate in 28 of 45 patients at the 5.8mg/kg dose selected for phase III testing, with median progression-free survival of 11.1 months in the BEHOLD-1 trial.
Grade 3 or higher treatment-related adverse events occurred in 71% of the 45 patients at the selected dose, predominantly haematologic, with treatment discontinuation in one patient and interstitial lung disease or pneumonitis in one patient.
The data will be presented in a late-breaking oral session at the European Society for Medical Oncology Congress in Madrid.
Five pivotal phase III trials are now under way across the programme: platinum-resistant ovarian cancer, platinum-sensitive ovarian cancer, first-line maintenance in ovarian cancer without homologous recombination deficiency, second-line endometrial cancer, and first-line maintenance in mismatch repair proficient endometrial cancer.
The update follows a run of oncology pipeline progress GSK has disclosed through the year, including September's reported 54% reduction in risk of death for risvutatug rezetecan against topotecan in small cell lung cancer, and the accelerated FDA approval secured in October for Jemperli in MSI-H/dMMR rectal cancer.
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The company's broader oncology build-out has also included the $10.6bn agreement to acquire Nuvalent, which closed in July and added three lung-cancer assets to the pipeline, and last month's agreement worth up to $750m for Chimagen's trispecific T-cell engager targeting multiple myeloma.