26 May 2026

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• Promising phase Ib results for velzatinib* (IDRX-42) support accelerating start of phase III trial in 1L gastrointestinal stromal tumours (GIST)  
• New Blenrep (belantamab mafodotin) results will highlight potential for long-term efficacy in relapsed or refractory multiple myeloma and meaningful activity in newly diagnosed patients
• Modelling data predict cure rate with Jemperli (dostarlimab) plus chemotherapy in dMMR/MSI-H primary advanced or recurrent endometrial cancer
• New analyses will show Ojjaara/Omjjara (momelotinib) delivers benefit across patient subgroups including when switching from ruxolitinib 

GSK plc (LSE/NYSE: GSK) will present new data from its expanding oncology portfolio and pipeline at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting (29 May - 2 June) in Chicago, IL and the 31st European Hematology Association (EHA) Congress (11 - 14 June) in Stockholm, Sweden. These findings demonstrate long-term outcomes for current therapies and pipeline expansion into additional tumour types and earlier treatment lines to advance practice-changing medicines for people with cancer.

First results for velzatinib in first-line (1L) advanced gastrointestinal stromal tumours (GIST) will show promising activity and tolerability across KIT mutations. These data have accelerated initiation of the StrateGIST Frontline phase III clinical trial given the need for therapies in 1L that broadly inhibit clinically relevant KIT variants, a key driver of relapse today.

• Data for velzatinib across clinically relevant KIT mutations in all lines, including 1L and second-line (2L) advanced GIST, will show encouraging anti-tumour activity and tolerability supporting the potential for a differentiated clinical profile (ASCO oral presentation abstract #11501).
• Analyses of velzatinib will show broad activity and substantial circulating tumour DNA (ctDNA) clearance of clinically meaningful KIT mutations and inhibition of GIST tumour cells (ASCO rapid oral presentation abstract #11520).

New DREAMM clinical trial programme data will show durable benefit with belantamab mafodotin combinations in relapsed or refractory multiple myeloma (RRMM) and potential in newly diagnosed multiple myeloma

• Four-year results from DREAMM-7 will show long-term efficacy, including overall survival, depth of response and health-related quality of life, reinforcing belantamab mafodotin with bortezomib and dexamethasone as a potential new standard of care in RRMM (EHA abstract #PS1862).
• DREAMM-8 long-term responder and sustained minimal residual disease negativity analyses will show depth and durability of response for patients treated with belantamab mafodotin in combination with pomalidomide and dexamethasone in RRMM (ASCO abstract #7565 and rapid oral presentation abstract #7515).
• In transplant-ineligible newly diagnosed multiple myeloma patients, final DREAMM-9 analysis will provide clinical evidence of meaningful activity with an optimised induction/maintenance dosing strategy of belantamab mafodotin (ASCO oral presentation abstract #7503).

Latest modelling data will predict the cure rate with dostarlimab plus chemotherapy in dMMR/MSI-H primary advanced or recurrent endometrial cancer, supporting patient care  

• New long-term analyses from the phase III RUBY trial will reinforce the sustained benefit of dostarlimab plus chemotherapy in patients with mismatch repair deficient/microsatellite instability-high (dMMR/MSI-H) primary advanced or recurrent endometrial cancer. Building from these results, new modelling analyses predict the proportion of patients who may be considered “cured”—defined as those who survive their disease and no longer experience disease-related mortality. These data complement traditional clinical trial measures, such as progression-free and overall survival, to support clinicians in advising their patients on treatment options and potential outcomes (ASCO oral presentation abstract #5501).

New analyses will show momelotinib can deliver symptom control across myelofibrosis patient subgroups and when switching from ruxolitinib 

• Post-hoc analyses from SIMPLIFY-1 and MOMENTUM will further build evidence for momelotinib across patient risk profiles in myelofibrosis, demonstrating consistent spleen, symptom and anaemia responses. Data will show earlier initiation of treatment before progression may be associated with better outcomes, underscoring the importance of initiating treatment before progression (EHA abstract #PS1995).
• New analyses from SIMPLIFY-1 and SIMPLIFY-2 will show that most patients in the trials could transition directly from ruxolitinib to momelotinib without acute symptom worsening. Symptoms remained stable or improved in the majority of patients. These data address a key challenge in treatment sequencing (EHA abstract #PS2001). 

Gastrointestinal stromal tumours (GIST) are the most common subtype of soft tissue sarcoma, with about 80,000 to 120,000 patients diagnosed with GIST per year worldwide.¹ GIST typically presents in the gastrointestinal tract with 80% of cases driven by mutations in the KIT gene that lead to the growth, proliferation and survival of tumour cells (primary or activating mutations in exons 9 and 11).² Additionally, about 90% of patients treated in the first-line develop new KIT mutations (secondary or resistance mutations in exons 13 and 17) that typically lead to relapse with limited therapeutic options.³ There are no approved tyrosine kinase inhibitors (TKIs) that inhibit the full spectrum of clinically relevant primary and secondary mutations in KIT.

Multiple myeloma is the third most common blood cancer globally and is generally considered treatable but not curable.^4,5 There are approximately more than 180,000 new cases of multiple myeloma diagnosed globally each year.⁶ Research into new therapies is needed as multiple myeloma commonly becomes refractory to available treatments.⁷ Many patients with multiple myeloma are treated in a community cancer setting, leaving an urgent need for new, effective therapies with manageable side effects that can be administered outside of an academic centre.^8,9

Endometrial cancer is found in the inner lining of the uterus, known as the endometrium. Endometrial cancer is the most common gynaecologic cancer in developed countries,¹⁰ with an estimated 1.6 million people living with active disease at any stage and 417,000 new cases reported each year worldwide.⁴ Incidence rates are expected to rise by approximately 40% between 2020 and 2040.¹¹ In Europe, approximately 121,000 people are estimated to be diagnosed with primary advanced or recurrent endometrial cancer each year.¹² Approximately 15-20% of patients with endometrial cancer will be diagnosed with advanced disease at the time of diagnosis.¹³ Among patients with primary advanced or recurrent endometrial cancer, approximately 75% have mismatch repair proficient/microsatellite stable tumours (MMRp/MSS).¹⁴

Myelofibrosis is a rare blood cancer that disrupts the body’s normal production of blood cells because of dysregulated Janus kinase (JAK)-signal transducer and activator of transcription protein signalling. The clinical hallmarks of myelofibrosis are splenomegaly (enlarged spleen), severely low blood counts, including anaemia and thrombocytopenia, and debilitating constitutional symptoms, such as fatigue, night sweats and bone pain, attributable to ineffective haematopoiesis and excessive production of proinflammatory cytokines.^15,16

Ovarian cancer is the eighth most common cancer in women worldwide.¹⁷ Despite high response rates to platinumbased chemotherapy in the first-line setting, approximately 85% of patients will experience disease recurrence. Once the disease recurs, it is rarely curable, with decreasing time intervals to each subsequent recurrence.¹⁸

Velzatinib is a highly selective, investigational small molecule tyrosine kinase inhibitor (TKI) designed to target all key KIT mutations in GIST. The US Food and Drug Administration (FDA) has granted velzatinib Fast Track designation for the treatment of patients with GIST after disease progression on or intolerance to imatinib, and Orphan Drug designations for the treatment of GIST.

Belantamab mafodotin is an antibody-drug conjugate comprising a humanised b-cell maturation antigen (BCMA) monoclonal antibody conjugated to the cytotoxic agent auristatin F via a non-cleavable linker. The drug linker technology is licensed from Seagen Inc.; the monoclonal antibody is produced using POTELLIGENT Technology licensed from BioWa Inc., a member of the Kyowa Kirin Group.

For product and important safety information, please consult the country’s relevant summary of product  characteristics:

• The EU product information is available at: BLENREP-EPAR-MEDICINE-OVERVIEW_EN.PDF-0  
• The US product information is available at: BLENREP-PI-MG.PDF  

Dostarlimab, a programmed death receptor-1 (PD-1)-blocking antibody, is the backbone of GSK’s ongoing immunooncology-based research and development programme. A robust clinical trial programme includes studies of dostarlimab alone and in combination with other therapies in gynaecologic, colorectal and lung cancers, as well as where there are opportunities for transformational outcomes.

Dostarlimab was discovered by AnaptysBio, Inc. and licensed to TESARO, Inc., under a collaboration and exclusive license agreement signed in March 2014. Under this agreement, GSK is responsible for the ongoing research, development, commercialisation and manufacturing of dostarlimab. 

For product and important safety information, please consult the country’s relevant summary of product  characteristics:

• The EU product information is available at: JEMPERLI-EPAR-PRODUCT-INFORMATION_EN.PDF  
• The US product information is available at: JEMPERLI-PI-MG.PDF 

Momelotinib has a differentiated mechanism of action, with inhibitory ability along three key signalling pathways: JAK1, JAK2, and activin A receptor, type I (ACVR1).^19,20,21,22 Inhibition of JAK1 and JAK2 may improve constitutional symptoms and splenomegaly.^19,20,22 Additionally, inhibition of ACVR1 leads to a decrease in circulating hepcidin levels, potentially contributing to anaemia-related benefit.^19,20,21,22

For product and important safety information, please consult the country’s relevant summary of product  characteristics:

• The EU product information is available at: OMJJARA-EPAR-PRODUCT-INFORMATION_EN.PDF
• The US product information is available at: OJJAARA-PI-PIL.PDF

Niraparib is an oral, once-daily Poly (ADP-ribose) polymerase (PARP) inhibitor indicated in the US for the maintenance treatment of adult patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to first-line platinum-based chemotherapy; and for the maintenance treatment of adult patients with deleterious or suspected deleterious germline BRCA-mutated recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy and who have been selected based on a US FDA-approved companion diagnostic for niraparib.

For product and important safety information, please consult the country’s relevant summary of product  characteristics:

• The EU product information is available at: ZEJULA-EPAR-PRODUCT-INFORMATION_EN.PDF
• The US product information is available at: ZEJULA-TABLETS-PI-PIL.PDF

Our ambition in oncology is to help increase overall quality of life, maximise survival and change the course of disease, expanding from our current focus on blood and women’s cancers into lung and gastrointestinal cancers, as well as other solid tumours. This includes accelerating priority programmes such as antibody-drug conjugates targeting B7-H3 and B7-H4, and IDRX-42, a highly selective KIT tyrosine kinase inhibitor.

GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at gsk.com.

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the “Risk Factors” section in GSK’s Annual Report on Form 20-F for 2025, and GSK’s Q1 Results for 2026. 

*United States Adopted Names Council approval pending for the name velzatinib

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