GSK acquires exclusive rights from Syndivia for antibody-drug conjugate (ADC) in prostate cancer

• Metastatic castration-resistant prostate cancer (mCRPC) remains a significant health burden for men with critical need for novel targeted treatments
• Agreement adds a new preclinical ADC with potential for enhanced anti-tumour activity and best-in-class profile
• ADC complements GSK's diverse pipeline in prostate cancer anchored by GSK'227, a B7H3-targeted ADC

GSK plc (LSE/NYSE: GSK) and Syndivia, a private biotechnology company focused on next-generation ADCs, today announced an agreement granting GSK exclusive worldwide rights to develop and commercialise a preclinical ADC for mCRPC.

Approximately 1.4 million men worldwide are diagnosed with prostate cancer each year and approximately 10-20% develop advanced disease, castration resistance with metastases, within five years.¹ For patients whose cancer has advanced to mCRPC, targeted treatment options are limited, and standard of care options may be difficult to access in community practice settings, and can be poorly tolerated with modest efficacy outcomes. Survival rates for these patients are low, with a 5-year survival rate of approximately 30% and a median survival of approximately two years.^2,3,4

The novel ADC, which utilises Syndivia's next-generation GeminiMab conjugation technology, has shown enhanced anti-tumour activity and an encouraging safety profile, demonstrating best-in-class potential. In preclinical studies, the ADC was effective at shrinking tumours without causing a proportional increase in significant side effects, even at higher doses. This ADC could provide a targeted treatment directly to the tumour, currently a gap in available therapies, along with a more easily accessible treatment in the community practice setting for mCRPC.

GSK is developing an innovative pipeline that spans ADCs with distinct antigens and payloads, next-generation small molecules, and T-cell engagers. These diverse approaches, such as GSK'227 and this novel ADC, enable GSK to advance potential therapeutic options across various stages and types of prostate cancer.

Hesham Abdullah, Senior Vice President, Global Head Oncology, R&D, GSK said: "Prostate cancer represents a significant health burden and an emerging area of growth for GSK, where targeted therapies are urgently needed in metastatic castration-resistant settings. The addition of this ADC builds on GSK's growing portfolio and strengths in tumour-targeted technologies, including GSK'227, our B7-H3-targeting ADC."

Sasha Koniev, Chief Executive Officer, Syndivia, said: "We are proud that GSK will advance this programme on a global scale. This agreement underscores the value of our GeminiMab ADC platform and the opportunity to bring a promising new therapy to patients with pressing unmet medical needs."

Financial considerations

Under the terms of the agreement, Syndivia will receive an upfront payment as well as success-based development and commercial milestone payments up to a total of £268 million. They will also receive tiered royalties on future product sales worldwide. GSK will assume full responsibility for the development, manufacturing, and worldwide commercialisation of the ADC program.

About Syndivia

Syndivia is a biotechnology company focused on the design and development of innovative antibody-drug conjugates. Its proprietary technology enables the creation of next-generation ADCs with optimized therapeutic profiles, aiming to expand treatment options for patients with cancer.

GSK in oncology

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.

About GSK

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.

Cautionary statement regarding forward-looking statements

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 2024, and GSK's Q2 Results for 2025.

References

1. Fatima, Hareer MBBSa; Rangwala, Hussain Sohail MBBSa; Riaz, Faiza MBBSa; Ali, Laiba MBBSa; Abbas, Syed R. MBBSb; Haque, Shajee UL MBBSa. Castration resistant prostate cancer: recent advances in novel therapeutic treatments. International Journal of Surgery: Global Health 7(1):e0400, January 2024. | DOI: 10.1097/GH9.0000000000000400
2. Huo X, Kohli M, Finkelstein J. Predicting Survival in Metastatic Castration-Resistant Prostate Cancer Patients: Development of a Prognostic Nomogram. Stud Health Technol Inform. 2025 Apr 8;323:164-168. doi: 10.3233/SHTI250070. PMID: 40200467.
3. Freedland, S.J., Davis, M., Epstein, A.J. et al. Real-world treatment patterns and overall survival among men with Metastatic Castration-Resistant Prostate Cancer (mCRPC) in the US Medicare population. Prostate Cancer Prostatic Dis 27, 327-333 (2024). https://doi.org/10.1038/s41391-023-00725-8
4. Chowdhury S, Bjartell A, Lumen N, Maroto P, Paiss T, Gomez-Veiga F, Birtle A, Kramer G, Kalinka E, Spaëth D, Feyerabend S, Matveev V, Lefresne F, Lukac M, Wapenaar R, Costa L. Real-World Outcomes in First-Line Treatment of Metastatic Castration-Resistant Prostate Cancer: The Prostate Cancer Registry. Target Oncol. 2020 Jun;15(3):301-315. doi: 10.1007/s11523-020-00720-2. PMID: 32500294; PMCID: PMC7283204.