GSK Showcases Strong Oncology Pipeline Data at ESMO Investor Update

Key Points

• Ris-rez delivered encouraging results in second-line small-cell lung cancer, with an objective response rate of about 61% and improved median overall survival versus topotecan (18.5 months vs. 10.3 months). It also significantly improved progression-free survival in relapsed or refractory osteosarcoma, though overall-survival data remain immature.
• Mo-rez showed strong activity in platinum-resistant ovarian cancer, achieving a 62% response rate at the selected dose, with a 12.2-month median duration of response and 11.1-month median progression-free survival. GSK has launched five Phase III trials across ovarian and endometrial cancers.
• GSK reported positive updates for its other oncology medicines: dostarlimab produced durable complete responses in many patients with dMMR/MSI-high rectal cancer, while JIDEYTRO achieved a 94% response rate in treatment-naive ROS1-positive lung cancer and showed strong activity against brain metastases.

GSK NYSE: GSK highlighted clinical data across its oncology pipeline at the European Society for Medical Oncology meeting, including updates for its B7-H3 antibody-drug conjugate ris-rez, B7-H4 ADC mo-rez, PD-1 therapy dostarlimab and ROS1 inhibitor JIDEYTRO.

Hesham Abdullah, GSK’s senior vice president and global head of oncology R&D, said the company presented more than 21 abstracts at ESMO. The briefing focused on recently presented clinical data and did not include third-quarter financial commentary.

Ris-rez Data in Small-Cell Lung Cancer and Osteosarcoma

In second-line small-cell lung cancer, Abdullah said data from GSK’s global Phase I-II program showed a 61% objective response rate at an 8 mg/kg dose of ris-rez. That result was broadly consistent with the 58% response rate reported in Hansoh’s China-based Phase III ARTEMIS-008 trial, he said.

ARTEMIS-008 compared ris-rez with topotecan in second-line small-cell lung cancer. GSK said the study showed a median overall survival of 18.5 months for ris-rez, compared with 10.3 months for topotecan. The overall-survival hazard ratio was 0.46. The company also cited a 58.3% objective response rate for ris-rez, versus 12.8% for topotecan.

GSK is recruiting patients for the EMBOLD-SCLC-301 Phase III study in second-line small-cell lung cancer using the 8 mg/kg dose and plans to initiate a first-line study before year-end.

The company also presented data on interstitial lung disease, an adverse event of interest for topoisomerase 1-based ADCs. Across GSK’s development program in solid tumors, grade 3 or higher ILD events occurred in 0.9% of patients, while all-grade events occurred in 4%, according to Abdullah.

Separately, a Phase III study in relapsed or refractory osteosarcoma compared ris-rez with gemcitabine plus docetaxel in 122 patients. The trial met its primary endpoint of blinded independent central review-assessed progression-free survival. Median PFS was 5.5 months with ris-rez and 1.1 months with chemotherapy. The objective response rate was 15% for ris-rez, compared with 2% for the control arm, while disease-control rates were 76% and 33%, respectively.

Overall-survival data from the osteosarcoma study were immature, with roughly 16% to 17% maturity, GSK said. The preliminary overall-survival hazard ratio was 0.51. The study used a 12 mg/kg dose, higher than the dose being used in GSK’s small-cell lung cancer program.

Mo-rez Shows Activity in Resistant Ovarian Cancer

GSK also updated results for mo-rez in platinum-resistant ovarian cancer. In the Phase I program, confirmed objective response rates rose across studied dose levels, reaching 62% at the selected 5.8 mg/kg every-three-weeks dose. At that dose, median duration of response was 12.2 months and median progression-free survival was 11.1 months, with 80% of patients progression-free at six months.

Abdullah said responses were observed across a range of B7-H4 expression levels. The safety profile was primarily characterized by gastrointestinal and myelosuppression-related events. At the 5.8 mg/kg dose, all-grade ILD occurred in 2% of patients. GSK plans to strongly recommend prophylactic G-CSF use in its Phase III studies to help mitigate neutropenia.

The company has initiated five Phase III trials for mo-rez across platinum-resistant and platinum-sensitive ovarian cancer, first-line maintenance ovarian cancer, second-line endometrial cancer and first-line maintenance endometrial cancer.

Dostarlimab Results in dMMR Rectal Cancer

GSK presented data from the AZUR-1 study of dostarlimab in locally advanced mismatch repair-deficient, microsatellite instability-high rectal cancer. The company recently announced U.S. regulatory approval in this setting.

Patients received nine doses, or about six months, of treatment. GSK reported a 68% clinical complete response rate at 12 months among patients with sufficient follow-up for the endpoint. It said 98% of clinical complete responses were durable to date, with no recurrences reported. When combining clinical complete responses at 12 months with pathologic complete responses, the rate was 76%.

Abdullah said the results could allow many patients to avoid chemotherapy and surgery, treatments that can affect gastrointestinal, urinary and fertility outcomes. The company characterized the safety profile as consistent with known immune-mediated adverse events for dostarlimab, with a low incidence of grade 3 events.

JIDEYTRO in ROS1-Positive Lung Cancer

GSK also referenced data presented at the World Conference on Lung Cancer for JIDEYTRO in treatment-naive patients with advanced ROS1-positive non-small-cell lung cancer. In 94 TKI-naive patients, independent review found a 94% objective response rate and a 15% complete response rate.

At 12 months, 86% of responding patients remained in response and 90% remained progression-free; median duration of response and median PFS had not been reached. Among patients with baseline brain metastases, GSK reported a 100% intracranial objective response rate and a 70% intracranial complete response rate.

JIDEYTRO was approved in the U.S. in late July, according to the company. GSK said the FDA is reviewing a first-line label for the medicine.

About GSK (NYSE:GSK)

GSK plc, formerly GlaxoSmithKline, is a global biopharmaceutical company headquartered in Brentford, England. The company focuses on researching, developing and commercializing medicines and vaccines designed to prevent and treat infectious diseases, respiratory conditions, immune-related disorders and certain cancers.

Its vaccine portfolio includes products such as Shingrix for shingles, Arexvy for respiratory syncytial virus (RSV) in older adults, and vaccines targeting meningitis, influenza and other infectious diseases.

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