GSK Shares Jump 3.83% as Twin Lung Cancer Drug Trial Wins Reinforce Its Growing Oncology Pipeline Bet

LONDON — Shares of GSK plc climbed 3.83% to $49.97 on the New York Stock Exchange Monday, adding $1.85, after the British pharmaceutical giant unveiled two sets of positive clinical trial results for lung cancer treatments at a major oncology conference in Seoul, South Korea.

The company's London-listed shares rose a similar amount, climbing roughly 3.4% to 1,830.5 pence and touching a session high of 1,837 pence, well above Friday's closing price of 1,770.5 pence. The gains came after GSK presented data at the 2026 World Conference on Lung Cancer showing strong results for two separate treatments: zidesamtinib, marketed under the brand name Jideytro, and Ris-Rez, a drug the company has licensed from China's Hansoh Pharmaceutical.

According to results reported by Reuters, the registrational phase I/II ARROS-1 trial for Jideytro showed a 94% objective response rate at 15.2 months of follow-up, with 90% of patients remaining progression-free at 12 months. The trial also found that 70% of patients with measurable brain metastases, a particularly difficult-to-treat complication of advanced lung cancer, achieved complete clearance of detectable brain tumors. GSK said it plans to submit the drug for U.S. regulatory approval later this year, seeking to expand its indication to first-line treatment for the specific genetic subset of lung cancer the drug targets.

The second dataset covered Ris-Rez, which GSK reported cut the risk of death by 54% compared with standard chemotherapy in patients with relapsed small cell lung cancer, an aggressive and historically difficult-to-treat form of the disease. The comparison was made against topotecan, a chemotherapy drug commonly used as a second-line treatment for the condition.

The dual readout reinforces the momentum behind GSK's broader push into oncology, which the company highlighted during its second-quarter 2026 earnings as a key growth driver alongside its established HIV treatment franchise, managed through its ViiV Healthcare joint venture, and a £1.9 billion cost-savings program aimed at improving overall profitability. Both Jideytro and Ris-Rez had already been flagged by GSK as potential best-in-class candidates within their respective treatment categories, and Monday's data was seen by investors as materially reducing the regulatory and commercial risk associated with both programs.

Not every analyst shared in the enthusiasm reflected in Monday's share price move. JPMorgan maintained its Underweight rating on GSK following the announcement and left its price target unchanged at 1,700 pence, a level that remained below where the stock was trading even before Monday's gains. That cautious stance stood in contrast to a more bullish view from Morgan Stanley, which raised its price target on GSK to 1,900 pence from 1,750 pence in late August, and RBC, which recently initiated coverage of the stock with a Sector Perform rating and a price target of 1,975 pence. Other firms have maintained more skeptical positions in recent weeks, with both Morgan Stanley's equity research desk and Barclays separately keeping Sell ratings on the stock ahead of Monday's data.

GSK's oncology push has been accompanied by a broader string of pipeline updates in recent weeks. The company disclosed positive Phase II data from an mRNA flu vaccine candidate on September 1, and separately advanced an early-stage lung drug through a new formulation study in late August. GSK also reported findings from a pediatric asthma trial in late August that the company said signaled long-term upside potential in the broader biologic drug market, and its ViiV Healthcare joint venture announced in late August that the U.S. Food and Drug Administration had approved Tivicay PD, a treatment within its HIV portfolio.

Monday's rally in GSK shares also came against a broadly supportive backdrop for the wider UK stock market. The FTSE 100 index opened higher Monday, with healthcare, software and energy stocks providing leadership, offering a tentative recovery after the index posted its worst weekly performance since July in the prior week. Energy stocks including BP and Shell also advanced Monday as Brent crude prices climbed above $107 a barrel amid escalating tensions in the Middle East, though that same rise in oil prices has stoked broader concerns about inflation and the path of interest rates in the United Kingdom. The Bank of England is due to announce its latest policy decision later this week, and rising energy costs have added to pressure on the central bank to consider further rate increases, a dynamic that has added a layer of uncertainty to the FTSE 100's broader recovery even as individual stocks like GSK posted standout gains.

For GSK specifically, Monday's clinical trial results provide concrete evidence that the company's multibillion-pound investment in expanding its oncology franchise is beginning to yield differentiated, clinically meaningful results, a development investors have been watching closely as the company works to diversify its revenue base beyond its traditional vaccines and general medicines businesses. Founded in 1715 and headquartered in London, GSK has increasingly positioned oncology alongside its established vaccines, HIV treatment and general medicines segments as a core pillar of its long-term growth strategy.

With a U.S. regulatory submission for Jideytro's expanded indication expected later this year, and continued late-stage development underway for Ris-Rez, investors are likely to watch closely in the coming months for further updates on both programs' regulatory progress, as well as any additional pipeline readouts that could further reshape Wall Street's mixed assessment of the stock, reflected in the current split between bullish price targets well above 1,900 pence and more cautious Underweight and Sell ratings that have persisted even after Monday's gains.