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RP-3500

Phase 1

Advanced Solid Tumor | Small molecule | Oncology |Repare Therapeutics Inc.|Last Updated: Dec 17, 2025

Target and mechanism

Molecular targetATR
Target classProtein Kinase
ModalitySmall molecule

Also known as RP-3500 (camonsertib)

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDBiomarker
Total Trials1
Total Enrollment276

FDA Designations

No designations recorded

Clinical trial landscape

RP-3500 · 2 trials · 3 indications

Phase 1 2
NCT05566574A Study of RP-3500 in Combination With Standard Radiation Therapy in People With Solid Tumor CancerSolid Tumor
ACTIVE NOT_RECRUITING49 Analytics
NCT04497116Study of RP-3500, Camonsertib, in Advanced Solid TumorsAdvanced Solid Tumor
COMPLETED276 Analytics
PHASE1ACTIVE NOT_RECRUITING
A Study of RP-3500 in Combination With Standard Radiation Therapy in People With Solid Tumor Cancer
Solid TumorUnlock trial analytics
PHASE1COMPLETED
Study of RP-3500, Camonsertib, in Advanced Solid Tumors
Advanced Solid TumorUnlock trial analytics

Study Endpoints

Primary Endpoints

Phase I - Safety and Tolerability of RP-3500 in combination with radiation therapy
2 years

by assessing the grade and frequency of adverse events and serious adverse events. A dose limiting toxicity (DLT) will be graded according to NCI CTCAE v5.0.

Phase II - Assess 6 month local control rate of patients with pathogenic ATM who received RP-3500 and palliative RT
2 years

Imaging per discretion of treating physician, and may include PET, CT and MRI imaging.

Frequency of Treatment-Related Adverse Event of CTCAE Grade 3 and Above
Start of treatment to 30 days post last dose, up to 1 year

Treatment-emergent adverse events (TEAEs) are those events that occur or worsen on or after the first dose of study drug up through 30 days post the last dose (or cross over to a different module) or the start of subsequent anticancer therapy. AEs are considered related to treatment if the relationship to camonsertib or the other combination drug (in the study regimen) is "Related" (include unknown relationship) as indicated on the AE eCRF page based on investigator's assessment.

Frequency of Dose Limiting Toxicity (DLT)
Either 21 days or 28 days (1 cycle) from the initiation of the study treatment.

Toxicity were assessed using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. A toxicity was considered dose-limiting if it occurred during the first cycle and was deemed at least possibly related to study treatment. If multiple toxicities occurred, the most severe toxicity was used in the assessment. The DLT Evaluable population consists of patients who received at least 80% of planned total doses of camonsertib , 80% of planned total doses of camonsertib and talazoparib, or 80% of planned total doses of camonsertib and 100% of gemcitabine; complete all required safety evaluations and are observed through the end of Cycle 1; or patients who experience a DLT qualifying event in the first cycle of treatment.

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Study Design & Arms

AllocationNA
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
RP-3500 in Combination With Standard Radiation TherapyEXPERIMENTALPatients with metastatic cancers with identified mutations in ATM will be enrolled. All patients will receive a standard palliative RT (4Gy x 5 fractions) on Days 1-5 in combination with RP-3500 on Days 1-5. In the first phase of the study, a 3+3 study design will be used to identify a safe dose of RP-3500 (starting at 80 mg QD) in combination with palliative RT.
Pilot subcohortEXPERIMENTALThe primary objective is to assess 6 month local control rate of patients of new metastatic lesions with pathogenic ATM who haves received prior RP-3500 and palliative RT.
RP-3500 (camonsertib) aloneEXPERIMENTALPhase 1: Multiple doses of RP-3500 (camonsertib) for oral administration alone
Expansion cohorts with RP-3500 (camonsertib)EXPERIMENTALPhase 2: Expansion cohorts with RP-3500 (camonsertib)
RP-3500 (camonsertib) with Talazoparib or GemcitabineEXPERIMENTALPhase 1: Multiple doses of RP-3500 (camonsertib) for oral administration in combination with talazoparib or gemcitabine

Interventions

NameTypeDescription
RP-3500DRUGRP-3500 on Days 1-5.
External Beam Radiotherapy (EBRT)RADIATIONPalliative radiation therapy (4Gy x 5 fractions) to a metastatic site on Days 1-5
RP-3500 (camonsertib)DRUGOral ATR inhibitor
TalazoparibDRUGOral PARP inhibitor
Gemcitabine InjectionDRUGGemcitabine
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites7

Inclusion Criteria: * Histologically confirmed malignancy with at least one metastatic lesion amenable to radiotherapy. Bone, visceral, and soft tissue are eligible. * Mutation in ATM (deleterious or VUS; somatic or germline; monoallelic or biallelic) * Note: Homozygous Deletion in the ATM gene ...

Countries:United StatesCanadaDenmarkUnited Kingdom
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Competitive Landscape -Other Solid Tumors 9 trials (matched to "Advanced Solid Tumor")

Frequently asked questions about RP-3500

What is RP-3500 used for?

RP-3500 is an investigational small molecule being studied for the treatment of advanced solid tumors and solid tumor cancers. It is being developed in oncology, with trials enrolling adults with advanced or metastatic solid tumors, including studies combining the drug with standard radiation therapy.

What does RP-3500 target?

RP-3500 targets ATR, a protein kinase involved in the DNA damage response. By inhibiting ATR, the drug is designed to interfere with cancer cell DNA repair processes. It is a small molecule therapeutic being evaluated in biomarker-selected patient populations with advanced solid tumors.

Who is developing RP-3500?

RP-3500 is being developed by Repare Therapeutics Inc., which trades under the ticker RPTX. The company is advancing the drug as an investigational therapy in oncology, with clinical studies conducted in the United States and several other countries including Canada, Denmark, and the United Kingdom.

What phase is RP-3500 in?

RP-3500 is in Phase 1 clinical development. It is an investigational drug and has not been approved by the FDA. The Phase 1 program includes a completed study in advanced solid tumors and an active Phase 1 study evaluating the drug in combination with standard radiation therapy.

What clinical trials is RP-3500 in?

RP-3500 has been studied in two Phase 1 trials. NCT04497116 was a completed Phase 1 study of RP-3500, also known as camonsertib, in advanced solid tumors with 276 participants. NCT05566574 is an active Phase 1 study of RP-3500 combined with standard radiation therapy in people with solid tumor cancer, with 49 participants.

Is RP-3500 the same as camonsertib?

Yes, RP-3500 is also known as camonsertib. The two names refer to the same investigational small molecule developed by Repare Therapeutics. The completed Phase 1 study in advanced solid tumors is listed under the name camonsertib, while the radiation combination study uses the RP-3500 designation.