Relay Therapeutics Advances Breast Cancer Combination Therapy into Phase 3 Trial
Event summary
- Relay Therapeutics plans a Phase 3 trial for zovegalisib + atirmociclib + AI in frontline endocrine-sensitive metastatic breast cancer, starting in early 2027.
- Early data from ReDiscover study showed a 44% objective response rate (ORR) in heavily pre-treated patients (median third-line), comparable to standard frontline therapies.
- Pfizer will supply atirmociclib for the Phase 3 trial, and Relay Therapeutics will fund and sponsor the study.
- Pharmacokinetic data indicate that atirmociclib increases zovegalisib exposure by 2.5-fold, with no impact in the reverse direction.
The big picture
Relay Therapeutics' strategy of targeting PI3Kα mutations represents a shift towards more precise cancer therapies, addressing a significant unmet need in breast cancer treatment. The combination approach with atirmociclib aims to mitigate the tolerability issues that have historically hampered PI3Kα inhibitors, potentially opening the door to frontline use. The partnership with Pfizer underscores the growing trend of collaboration between smaller biotech firms and larger pharmaceutical companies to accelerate drug development.
What we're watching
- Regulatory Risk
- The Phase 3 trial initiation is contingent on regulatory feedback, which could significantly alter the trial design or delay progress.
- Clinical Efficacy
- The Phase 3 trial's success hinges on whether the observed ORR in heavily pre-treated patients translates to a meaningful improvement in progression-free survival in a frontline setting.
- Commercialization
- Relay Therapeutics' ability to secure broader partnerships or licensing agreements for zovegalisib will be crucial for maximizing the commercial potential of the therapy.
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