Lunresertib plus camonsertib produces durable responses in advanced endometrial and ovarian cancer in early trial data

Evidence stage: Emerging ClinicalRegulatory status: InvestigationalGuideline status: Not addressed

The combination of lunresertib (a PKMYT1 inhibitor) and camonsertib (an ATR inhibitor) produced durable responses in heavily pretreated patients with advanced endometrial cancer and separately in patients with platinum-resistant ovarian cancer, in the gynecologic expansion cohort of the phase 1, first-in-human MYTHIC trial (ClinicalTrials.gov NCT04855656), according to data presented at the American Association for Cancer Research (AACR) 2025 annual meeting. In the endometrial-cancer cohort (n=27), the reported overall response rate was 25.9% and the 24-week progression-free-survival rate was 43%; in the platinum-resistant ovarian-cancer cohort (n=24), the reported overall response rate was 37.5% and the 24-week progression-free-survival rate was 45%. The FDA reportedly granted Fast Track designation to this combination for both CCNE1-amplified/FBXW7- or PPP2R1A-mutated platinum-resistant ovarian cancer and for the analogous endometrial-cancer population; this is sourced only to company/trade-press reporting, not a direct FDA-published record, and is presented here as a reported claim requiring direct regulatory corroboration before being treated as confirmed regulatory fact — the FDA does not publish a searchable public list of individual Fast Track grants, the same structural sourcing limitation already disclosed elsewhere on this site for investigational, trial-status-only records. No FDA approval exists for this combination.

What This Means

In the gynecologic expansion cohort of the first-in-human, phase 1 MYTHIC trial, the combination of lunresertib (a PKMYT1 inhibitor) and camonsertib (an ATR inhibitor) produced durable objective responses in heavily pretreated patients with advanced endometrial cancer (reported 25.9% overall response rate, n=27) and, in a separate cohort of the same trial, in platinum-resistant ovarian cancer (reported 37.5% overall response rate, n=24). The FDA reportedly granted Fast Track designation to this combination for both cancer types, based on sponsor/trade-press reporting rather than a direct FDA-published record.

What This Doesn't Mean

This is single-arm, early-phase (phase 1) response data from a first-in-human dose-escalation/expansion trial, not a randomized comparison, and this combination has no FDA approval. The reported Fast Track designation must not be presented as an FDA-confirmed fact — it is a reported claim pending direct regulatory corroboration, the same treatment already applied to Batch 2's PT217 record for the identical structural reason (the FDA does not publish a searchable list of individual Fast Track grants).

Why It Matters

Durable responses in two difficult-to-treat, heavily pretreated gynecologic cancer populations from a genuinely new drug-class combination (a PKMYT1 inhibitor plus an ATR inhibitor) represents an early but real signal worth tracking as this combination moves toward later-phase study.

Promise & Proof

Proof — strength of the evidence 3 / 5
  • Base score from evidence stage: Emerging Clinical.
Promise — potential significance if later evidence holds up 2 / 5
  • Baseline — a validly-evidenced story starts here; every further point below is an explicit, checkable reason.
  • The record includes substantive editorial reasoning about why this discovery matters.

These two ratings are automatically computed from this story's own structured evidence fields and are shown separately on purpose — they are never combined into one score. They describe this record, not a medical recommendation: they do not establish medical certainty, do not substitute for reading the cited sources, and are recalculated whenever the underlying evidence changes.

Population / Applicability

Studied in: Adults with advanced, heavily pretreated endometrial cancer (n=27 in this cohort), enrolled in the gynecologic expansion cohort of a first-in-human, phase 1 trial. A separate cohort of the SAME trial (n=24) enrolled patients with platinum-resistant ovarian cancer; both cohorts' results are reported together here since they come from the same combination and the same trial, though this record's cancer_type taxonomy tag reflects the endometrial cohort specifically. (Adults)

Eligibility in both cohorts is restricted to heavily pretreated, molecularly-relevant patients (the Fast Track-eligible subgroup is further restricted to CCNE1-amplified or FBXW7/PPP2R1A-mutated tumors) — should not be presented as broadly available or equivalent-strength evidence to a completed randomized trial. Registry status is time-sensitive and should be re-checked before publication.

Full evidence details
Study design
Non-randomized trial
Sample size
27

Funding & Conflicts

Sponsor: Repare Therapeutics — not independently confirmed against a primary corporate-disclosure document.

Regulatory status by jurisdiction

Unspecified jurisdiction

Status
Investigational
Last verified
2026-08-13

This record has no structured cancer-type scope on file yet — editorial review recommended before treating it as applicable to a specific cancer type.

Guideline positions

Guideline

Position
Not addressed
Last verified
2026-08-13

Primary evidence supporting this story

Why Should I Trust This?

  • 1 source at Tier 1 — Government/regulatory authority (FDA, NCI, NIH, ClinicalTrials.gov, CDC, and equivalent)
  • Last reviewed: 2026-08-13

This panel summarizes real, checkable facts about this record's own sources and review status — it is not a trust score, and reading it is not a substitute for reading the cited sources yourself.

Discovery Timeline

Every recorded change to this record's content or publication status, in order.

  1. Status change — Status changed from "Legacy / Unverified" to "In editorial review".
  2. Status change — Status changed from "In editorial review" to "Verified".

Last reviewed

Related discoveries

Lunresertib plus camonsertib produces durable responses in advanced endometrial and ovarian cancer in early trial data

https://cancerdiscoveries.com/discoveries/lunresertib-plus-camonsertib-produces-durable-responses-in-advanced-endometrial-and-ovarian-cancer-in-early-trial-data/

Evidence stage: Emerging Clinical

What This Means

In the gynecologic expansion cohort of the first-in-human, phase 1 MYTHIC trial, the combination of lunresertib (a PKMYT1 inhibitor) and camonsertib (an ATR inhibitor) produced durable objective responses in heavily pretreated patients with advanced endometrial cancer (reported 25.9% overall response rate, n=27) and, in a separate cohort of the same trial, in platinum-resistant ovarian cancer (reported 37.5% overall response rate, n=24). The FDA reportedly granted Fast Track designation to this combination for both cancer types, based on sponsor/trade-press reporting rather than a direct FDA-published record.

What This Doesn't Mean

This is single-arm, early-phase (phase 1) response data from a first-in-human dose-escalation/expansion trial, not a randomized comparison, and this combination has no FDA approval. The reported Fast Track designation must not be presented as an FDA-confirmed fact — it is a reported claim pending direct regulatory corroboration, the same treatment already applied to Batch 2's PT217 record for the identical structural reason (the FDA does not publish a searchable list of individual Fast Track grants).

Why It Matters

Durable responses in two difficult-to-treat, heavily pretreated gynecologic cancer populations from a genuinely new drug-class combination (a PKMYT1 inhibitor plus an ATR inhibitor) represents an early but real signal worth tracking as this combination moves toward later-phase study.

Primary sources

  • MYTHIC trial registry (phase 1 study of lunresertib plus camonsertib in advanced solid tumors, gynecologic expansion cohort) — https://clinicaltrials.gov/study/NCT04855656 (NCT04855656)

Date verified: 2026-08-13

Correction status: No correction or retraction