RE: BIO Europe Spring.25 Mar 2026 10:17
Source Grok -
Q Merck KGaA have trials underway for Tuvusertib (ATR inhibitor) and M9466 (PARP inhibitor). How advanced are these trials, how successful so far?
A Tuvusertib (M1774, oral ATR inhibitor) is more advanced, with completed Phase I data and multiple ongoing/recently initiated Phase II combination trials (as of early 2026). M9466 (selective PARP1 inhibitor, also known as HRS-1167, licensed from Hengrui) remains in early Phase I/Ib development, primarily in combination dose-finding studies.
Tuvusertib (ATR inhibitor)Trial advancement:
The first-in-human Phase I monotherapy trial (DDRiver Solid Tumors 301; NCT04170153) is complete (active, not recruiting). It established safety, pharmacokinetics/pharmacodynamics (PK/PD), and a recommended dose (e.g., 180 mg QD on a 2 weeks on/1 week off schedule).
It has progressed to Phase Ib/II and Phase II combination studies.
M9466 (PARP1 inhibitor)Trial advancement:
This is earlier-stage. Hengrui’s original first-in-human Phase I (pre-licensing) has reported data. Merck KGaA-initiated trials are Phase I/Ib combination dose-finding studies (no Phase II monotherapy or pivotal trials yet).
Overall context: Both assets are part of Merck KGaA’s DDR (DNA damage response) inhibitor portfolio, with a strategy emphasizing combinations (ATR + PARP or other DDR/ICI/chemo) in biomarker-selected, resistant, or hard-to-treat solid tumors. Tuvusertib has clearer proof-of-concept and is farther along; M9466 is still de-risking in early combinations. No approvals or Phase III data exist for either, and larger efficacy readouts (e.g., from DDRiver EOC 302) are expected in the coming 1–2 years. For the absolute latest status, check ClinicalTrials.gov (NCT numbers above) or Merck’s pipeline updates, as trials can evolve.