GSK Shares Edge Lower Despite Double Dose of Pipeline Good News

GSK plc (LSE/NYSE: GSK) shares slipped slightly in early Monday trading, even as the pharmaceutical giant unveiled two regulatory milestones for its oncology and hepatology portfolios.

The US Food and Drug Administration has accepted for priority review a supplemental Biologics License Application for Jemperli (dostarlimab) in previously untreated stage II and III dMMR/MSI-H locally advanced rectal cancer, setting a PDUFA action date of February 2027.

The submission, backed by data from the phase II AZUR-1 trial, showed a meaningful proportion of the 154 participants remained free of detectable cancer a year or more after treatment. If approved, Jemperli could become the first immunotherapy to spare some patients from chemotherapy, radiation and surgery.

The application, accepted under the FDA’s Project Orbis scheme for coordinated international review, is also eligible for expedited assessment via the National Priority Voucher programme.

Separately, GSK secured its first global approval for Hibsago (bepirovirsen) after Japan’s Ministry of Health, Labour and Welfare cleared the antisense oligonucleotide as a functional cure for chronic hepatitis B in adults who have completed at least six months of prior nucleoside analogue therapy.

The approval, accelerated via Japan’s SENKU designation, was underpinned by B-Well phase III data showing a 19% functional cure rate versus roughly 1% for standard care alone. Chief Scientific Officer Tony Wood called it “a major advance” for hepatitis B management, with US and other regulatory decisions expected in coming months.

Despite the encouraging clinical and regulatory progress on two fronts, investors showed a muted reaction, with GSK stock trading marginally lower on the day.