# Lunresertib

Source: https://onco.cc/drugs/lunresertib/  
OnCo record `lunresertib` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Lunresertib is an experimental oral small molecule kinase inhibitor from Repare Therapeutics, in phase 2 trials for advanced solid tumours, ER-positive HER2-negative breast cancer resistant to CDK4/6 inhibitors and TP53-mutant ovarian and uterine cancer.

## Summary

Lunresertib (RP-6306) is an oral small molecule kinase inhibitor from Repare Therapeutics, with Debiopharm as licensee. A first-in-class oral inhibitor of PKMYT1, a cell-cycle kinase; developed alone and with Debiopharm's WEE1 inhibitor Debio 0123 (zedoresertib). Its furthest stage is phase 2, for advanced solid tumours, ER-positive HER2-negative breast cancer resistant to CDK4/6 inhibitors (platform trial) and TP53-mutant ovarian and uterine cancer (with carboplatin and paclitaxel). ClinicalTrials.gov registers it in 6 studies linked below. Exclusively licensed worldwide to Debiopharm on 15 July 2025; Debiopharm took over sponsorship of the MYTHIC study (NCT04855656, recruiting). Phase 2 use is in the Canadian Cancer Trials Group platform NCT05601440 (recruiting) and NCT05605509 (completed). Whether it works in people has not been established unless a trial below reports it.

## Fields

- Kind: Treatment
- Status: phase-2
- Last checked: 2026-11-03
- Also known as: RP-6306
- Tags: pipeline; ctgov-ingest
- Code: RP-6306
- Modality: Oral small molecule kinase inhibitor
- Mechanism: A first-in-class oral inhibitor of PKMYT1, a cell-cycle kinase; developed alone and with Debiopharm's WEE1 inhibitor Debio 0123 (zedoresertib).

## Sources

- Repare Therapeutics: sec.gov: https://www.sec.gov/Archives/edgar/data/1808158/000119312525159942/d944012dex991.htm
- Repare Therapeutics: sec.gov: https://www.sec.gov/Archives/edgar/data/1808158/000119312525159942/d944012dex991.htm
- Repare Therapeutics: clinicaltrials.gov: https://clinicaltrials.gov/api/v2/studies/NCT04855656
- ClinicalTrials.gov: trials of RP-6306: https://clinicaltrials.gov/search?intr=RP-6306

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Metastatic cancer (cancer that has spread)](https://onco.cc/cancers/metastatic-cancer/)
- companies: [Debiopharm](https://onco.cc/companies/debiopharm/), [Repare Therapeutics](https://onco.cc/companies/repare-therapeutics/)
- trials: [Liquid-biopsy Informed Platform Trial to Evaluate CDK4/6-inhibitor Resistant ER+/HER2- Metastatic Breast Cancer](https://onco.cc/trials/nct05601440/), [Phase 1 Study of RP-6306 With Carboplatin and Paclitaxel in TP53 Ovarian and Uterine Cancer](https://onco.cc/trials/nct06107868/), [RP-6306 in Patients With Advanced Cancer](https://onco.cc/trials/nct05605509/), [Study of Lunresertib Alone or in Combination With RP-3500 or Zedoresertib (Debio 0123) in Patients With Advanced Solid Tumors](https://onco.cc/trials/nct04855656/), [Study of RP-6306 With FOLFIRI in Advanced Solid Tumors](https://onco.cc/trials/nct05147350/), [Study of RP-6306 With Gemcitabine in Advanced Solid Tumors](https://onco.cc/trials/nct05147272/)

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