British drugmaker GSK plc (NYSE:GSK) is betting on blockbuster potential for its experimental cancer therapy Mo-rez, after early trial data showed the drug shrank tumors in patients with advanced, hard-to-treat gynecological cancers.

“Do we think it would be a blockbuster? Yes, absolutely,” GSK’s head of oncology research, Hesham Abdullah, told reporters on Sunday, as the data was presented at a medical conference in Puerto Rico, according to Reuters.

In platinum-resistant ovarian cancer, 62% of patients achieved at least a 30% reduction in tumor size. In endometrial cancer, 67% met that threshold.

Mo-rez is an antibody-drug conjugate that targets the B7H4 protein found on gynecological cancer cells but largely absent from healthy tissue. GSK licensed the drug from China’s Hansoh Pharma in 2023. The ADC market is projected to reach $31 billion by 2030.

Pipeline Momentum Builds Under New CEO

The results add momentum to GSK’s fast-growing oncology business. CEO Luke Miels, who took the role in January, has pushed for a faster development pace. GSK is currently running two late-stage trials for Mo-rez in ovarian and endometrial cancers and plans to launch three additional studies in the coming months.

Broader Portfolio Strengthens GSK’s Position

The Mo-rez data comes as GSK continues to build out its portfolio. The FDA approved its severe asthma treatment Exdensur in December 2025, with trial data showing a 58% reduction in asthma exacerbations. In March 2026, the FDA expanded the approved age indication for its RSV vaccine Arexvy to adults aged 18 to 49 at higher risk, broadening its addressable market.

GSK has also joined the Trump administration’s TrumpRx.gov platform, offering discounts on several drugs, including a 55% reduction on its COPD treatment, Incruse.

Disclaimer: This content was produced with the help of AI tools and was reviewed and published by Benzinga editors.

Photo courtesy: HJBC via Shutterstock