GSK Terminates Collaboration with IDEAYA Biosciences, Returns Two Synthetic Lethality Drug Candidates IDE275 and IDE705

In recent years, synthetic lethality has emerged as a unique precision treatment strategy and gained widespread attention in the field of cancer therapy.Focus and Application. Especially with the successful launch of multiple PARP inhibitors, which have shown a rapidly growing sales trend, further intensifying global enthusiasm for synthetic lethality research and attracting widespread strategic investments from pharmaceutical companies.

But recently, GSK announced the termination ofIDEAYA Biosciences' Collaboration on Synthetic Lethality Drugs for Solid Tumors Returns Two Clinical Programs, IDE275 andIDE705, Represents GSK Once Again Abandoning the Development of Synthetic Lethality Mechanism DrugsEffort.

BesidesMarketedApart from niraparib, GSK's investments in synthetic lethality in recent years have largely ended in failure.

First in 2017, GSK took the lead in abandoningOne of the three projects in collaboration with Epizyme continues to advance.PRMT5 and PRMT1 Projects.

Subsequently, in February 2022,GSK has completely terminated its partnership withEpizyme Collaboration, ReturnedPRMT5 inhibitor GSK3326595 and PRMT1 inhibitor GSK3368715 rights, with limited mention of the reasons for termination. According to reports, it is possibly due to GSK's decreased prioritization of the development of the synthetic lethality mechanism, as well asPRMT5 Inhibitor GSK3326595 inSerious side effects were observed in clinical studies.

Gave upFollowing the PRMT5 and PRMT1 projects,GSK returned in the second quarter of 2022 withCollaboration with IDEAYA BiosciencesMAT2A ProjectIDE397。——The original purpose of the IDE397 collaboration was with GSK'sThe combination of PRMT5 and PRMT1 inhibitors, following GSK's abandonmentPRMT5 and PRMT1,The cooperation significance of IDE397 is not great. As GSK has returnedIDE397，IDEAYA Biosciences RegainsGlobal rights of IDE397.

December 2025, GSK toIDEAYAThe company announced the decision to terminate the Cooperation, Option and License Agreement signed on June 15, 2020. According to the terms of the agreement, the termination will take effect within 90 days from GSK's written notice. During the 90-day transition period, GSK willWerner Helicase (IDE275) andpol theta（IDE705) Two clinical programs returned to IDEAYACompany. —— GSK did not state the reason for terminating the cooperation. Notably, GSK andAt the time IDEAYA initially reached the collaboration, all three collaborative projects were in the preclinical stage, and they had advanced to the clinical stage by the time of relinquishment.

Regarding the termination of the cooperation with GSK,IDEAYA Biosciences stated that this does not affect its pipeline progress, and it is expected to report its main core pipeline by the end of this year or early next year.GNAQ/11 InhibitorPhase II/III data of darovasertib. In addition, the Werner helicase program returned by GSK (IDE275) andPol Theta Project (IDE705), IDEAYA Biosciences will explore strategic options next year, including seeking new partners or advancing internally, with the final decision depending on new data.

In fact,The prospect of synthetic lethality mechanisms is broad, but their development is challenging. Currently, all successful synthetic lethality mechanism drugs arePARP inhibitor.

References:

1.https://app.quotemedia.com/data/downloadFiling?webmasterId=101533&ref=319629836&type=HTML&symbol=IDYA&cdn=c44b0914dfde730c43ab9c38511fc3dd&companyName=IDEAYA+Biosciences+Inc.&formType=8-K&dateFiled=2025-12-05

2.https://www.biospace.com/business/gsk-cuts-five-year-old-cancer-collaboration-with-ideaya

3.https://www.prnewswire.com/news-releases/ideaya-biosciences-inc-reports-second-quarter-2022-financial-results-and-provides-business-update-301605448.html

4.https://www.ideayabio.com/pipeline/

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