8-K: OnKure Therapeutics Announces Positive Preliminary Data for OKI-219 in First-in-Human Trial

OnKure Therapeutics reports encouraging preliminary safety, tolerability, and pharmacokinetic data from its first-in-human trial of OKI-219, a mutant-selective PI3K inhibitor.

Summary

• OnKure Therapeutics has released preliminary data from its PIKture-01 trial for OKI-219, a PI3K inhibitor.
• The trial included 17 patients across three dose levels: 300 mg, 600 mg, and 900 mg twice daily.
• OKI-219 was well-tolerated with no dose-limiting toxicities, interruptions, or reductions.
• The most common adverse events were grade 1 diarrhea, nausea, and pruritus.
• Pharmacokinetic data shows that OKI-219 achieves steady-state exposure levels with near-continuous coverage of the in vivo EC80 for pAKT inhibition at the 900mg dose.
• Two patients with HR+/HER2breast cancer showed prolonged stable disease, with one experiencing a >95% reduction in PIK3CA H1047R ctDNA.
• Preclinical data indicates synergistic activity when OKI-219 is combined with SERD and CDK4/6 inhibitors.
• The company plans to provide additional single-agent and initial combination data in the second half of 2025.
• OnKure is also developing a pan-mutant PI3K inhibitor and a highly selective allosteric inhibitor targeting specific PI3K mutations, with development candidates expected in 2025 and 2026 respectively.

Sentiment

Score: 8

Explanation: The document presents very positive preliminary clinical data for OKI-219, with strong safety and tolerability results, and promising preclinical data. The company also has a clear strategy for future development and is well-funded. However, it is still early-stage data and there are inherent risks in drug development.

Positives

• OKI-219 demonstrated a favorable safety profile with only grade 1 treatment-related adverse events.
• The pharmacokinetic data supports pharmacologically relevant exposures, even at the lowest assessed dose levels.
• Preclinical data suggests strong combination activity with standard-of-care therapies.
• The company is expanding its pipeline to target a broader range of PI3K mutations.
• The company has sufficient cash to fund operations through multiple clinical milestones and into Q4 2026.

Negatives

• The data presented is preliminary and from a small number of patients.
• The company has a limited operating history and has incurred significant net losses since inception.
• The company faces substantial competition in the development of cancer therapies.

Risks

• The company has a limited operating history and has incurred significant net losses since inception.
• There is a risk of adverse events, toxicities, or other undesirable side effects from the drug.
• The company may face delays or difficulties in the enrollment or maintenance of patients in clinical trials.
• The company may not be able to obtain regulatory approval for its product candidates.
• The company faces substantial competition in the discovery, development, and commercialization of products.
• The company relies on third parties for manufacturing and research, which introduces risk.
• The company may not be able to protect its intellectual property.

Future Outlook

The company plans to provide additional single-agent data and initial combination data with fulvestrant in the second half of 2025, and expects to announce development candidates for pan-mutant and allosteric inhibitors in 2025 and 2026, respectively.

Management Comments

• Nicholas Saccomano, Ph.D., President and CEO, stated that the preliminary data shows OKI-219 was very well tolerated and presents a favorable safety profile.
• He also noted that the clinical PK data shows consistent steady-state exposure with near-continuous target coverage at levels where clinical activity is consistently observed.

Industry Context

The announcement is significant as it provides initial clinical data for a highly selective PI3KH1047R inhibitor, a target of interest in oncology. The company is positioning OKI-219 as a potential best-in-class treatment, with a focus on mutant selectivity to improve efficacy and safety compared to existing PI3K inhibitors.

Comparison to Industry Standards

• The document mentions that there are three approved PI3K inhibitors (alpelisib, capivasertib, and inavolisib), but they have on-target toxicity that limits dosing and decreases quality of life.
• OnKure is developing mutant-selective inhibitors designed to preserve wild-type PI3Ka, which is a key differentiator from existing therapies.
• The document compares OKI-219's selectivity to other PI3KH1047R inhibitors, showing it has a selectivity of ~100x for H1047R vs wild type, while other inhibitors have much lower selectivity.
• The company is also developing a pan-mutant PI3K inhibitor and a highly selective allosteric inhibitor targeting specific PI3K mutations, which is a novel approach compared to existing therapies.

Stakeholder Impact

• Shareholders will likely react positively to the encouraging clinical data and the company's progress in drug development.
• Patients with PI3K-mutated cancers may benefit from the development of OKI-219 and other therapies in the pipeline.
• Employees may be motivated by the positive results and the company's potential for growth.
• The company's success could lead to increased collaboration opportunities with other pharmaceutical companies and research institutions.

Next Steps

• The company will continue the PIKture-01 trial, including Part 1b evaluating OKI-219 in combination with fulvestrant.
• The company expects to provide additional single agent data and initial combination data with fulvestrant in the second half of 2025.
• The company will continue to pursue additional early-stage discovery programs targeting oncogenic mutations of PI3K.
• The company expects to announce a pan-mutant development candidate in the first half of 2025.
• The company expects to announce a development candidate for a highly selective allosteric inhibitor molecule in 2026.

Key Dates

Keywords

OKI-219, PI3K inhibitor, cancer therapy, clinical trial, breast cancer, oncology, pharmacokinetics, drug development, mutant-selective, PIKture-01