News Releases

• Selected a potential first-in-class Pol Theta Helicase development candidate in collaboration with GSK
• Observed complete responses in preclinical combination studies of Pol Theta Helicase DC with niraparib in multiple in vivo PDX and CDX HRD models
• Targeting first-in-human clinical evaluation of Pol Theta Helicase DC combination with niraparib in H1 2023 for patients having tumors with HRD
• Potential to receive up to $960 million in aggregate milestones from GSK, including up to $485 million in aggregate development and regulatory milestones and up to $475 million in aggregate commercial sales milestones

SOUTH SAN FRANCISCO, Calif., June 28, 2022 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a synthetic lethality focused precision medicine oncology company committed to the discovery and development of targeted therapeutics, announced selection of a potential first-in-class Pol Theta Helicase development candidate (DC). 

The Pol Theta Helicase DC is a potential first-in-class small molecule inhibitor of the helicase domain of DNA Polymerase Theta.  IDEAYA is collaborating with GSK on IND-enabling studies to support the evaluation of the Pol Theta Helicase DC in combination with niraparib, GSK's PARP inhibitor, for patients having tumors with BRCA or other homologous recombination (HR) mutations or homologous recombination deficiency (HRD). 

"We are excited about potential clinical development opportunities for this potential first-in-class Pol Theta Helicase inhibitor. Pol Theta promotes DNA repair by Microhomology-Mediated End-Joining (MMEJ), an error-prone mutagenic DNA repair pathway, which is active in BRCA mutant and other HRD cancer cells.  PARP1 is also involved in MMEJ DNA repair, supporting a hypothesis for synergistic combination of our Pol Theta Helicase DC with niraparib," said Michael White, Senior Vice President and Chief Scientific Officer of IDEAYA Biosciences. 

"The development candidate has demonstrated robust in vivo efficacy in combination with niraparib, with significant tumor regressions and durable responses in multiple cancer models.  We believe the Pol Theta helicase and niraparib combination has the opportunity to deliver meaningful patient benefit," said Benjamin Schwartz, Ph.D., Vice President, Head of Oncology Synthetic Lethality Research Unit at GSK. 

IDEAYA and GSK are targeting an IND submission for the Pol Theta Helicase DC, subject to satisfactory completion of ongoing preclinical and IND-enabling studies, to enable first-in-human studies in the first half of 2023. 

IDEAYA and GSK are collaborating on the ongoing IND-enabling studies, and GSK will lead clinical development for the Pol Theta program.  GSK holds a global, exclusive license to develop and commercialize the Pol Theta Helicase DC and is responsible for all research and development costs for the program, including those incurred by IDEAYA. IDEAYA is eligible to receive future development and regulatory milestones of up to $485 million aggregate, inclusive of preclinical and clinical milestones of up to $10 million aggregate for advancing this asset through IND effectiveness. 

Upon potential commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones and tiered royalties on global net sales by GSK, its affiliates and their sublicensees ranging from high single digit to sub-teen double digit percentages, subject to certain customary reductions.

IDEAYA is a synthetic lethality focused precision medicine oncology company committed to the discovery and development of targeted therapeutics for patient populations selected using molecular diagnostics.  IDEAYA's approach integrates capabilities in identifying and validating translational biomarkers with drug discovery to select patient populations most likely to benefit from its targeted therapies.  IDEAYA is applying its research and drug discovery capabilities to synthetic lethality – which represents an emerging class of precision medicine targets.  

This press release contains forward-looking statements, including, but not limited to, statements related to (i) the timing of IND submission and first-in-human clinical evaluation of Pol Theta Helicase DC combination with niraparib and (ii) the potential receipt of GSK milestone payments. Such forward-looking statements involve substantial risks and uncertainties that could cause IDEAYA's preclinical and clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the drug development process, including IDEAYA's programs' early stage of development, the process of designing and conducting preclinical and clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing drug products, IDEAYA's ability to successfully establish, protect and defend its intellectual property, the effects on IDEAYA's business of the worldwide COVID-19 pandemic, the ongoing military conflict between Russia and Ukraine, and other matters that could affect the sufficiency of existing cash to fund operations. IDEAYA undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of IDEAYA in general, see IDEAYA's recent Quarterly Report on Form 10-Q filed on May 10, 2022 and any current and periodic reports filed with the U.S. Securities and Exchange Commission.

SOURCE IDEAYA Biosciences, Inc.