Study of RP-6306 Alone or in Combination With RP-3500 in Patients With Advanced Solid Tumors (MYTHIC)
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ClinicalTrials.gov Identifier: NCT04855656 |
Recruitment Status :
Recruiting
First Posted : April 22, 2021
Last Update Posted : May 6, 2023
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Condition or disease | Intervention/treatment | Phase |
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Advanced Solid Tumor | Drug: RP-6306 Drug: RP-3500 | Phase 1 |
Phase 1, multi-center, open-label, dose-escalation study to:
- Evaluate the safety profile and MTD of RP-6306 alone and in combination with RP-3500 when administered orally to establish the recommended Phase 2 dose and schedule
- Characterize the PK and pharmacodynamics of RP-6306 alone and in combination with RP-3500
- Assess preliminary anti-tumor activity associated with RP-6306 alone and in combination with RP-3500
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 180 participants |
Allocation: | Non-Randomized |
Intervention Model: | Single Group Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Phase 1 Study of the Safety, Pharmacokinetics, Pharmacodynamics and Preliminary Clinical Activity of RP-6306 Alone or in Combination With RP-3500 in Patients With Advanced Solid Tumors |
Actual Study Start Date : | April 30, 2021 |
Estimated Primary Completion Date : | October 30, 2023 |
Estimated Study Completion Date : | December 31, 2024 |
Arm | Intervention/treatment |
---|---|
Experimental: Phase 1: RP-6306 Single-Agent, Dose Escalation and Food-effect Study
Patients receive RP-6306 orally until disease progression, unacceptable toxicity, or investigator/patient decision. Dose escalation will proceed until a maximum tolerated dose is identified.
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Drug: RP-6306
Oral PKMYT1 Inhibitor |
Experimental: Phase 1: RP-6306 in combination with RP-3500, Dose Escalation Study
Patients receive RP-6306 with RP-3500 orally until disease progression, unacceptable toxicity, or investigator/patient decision. Dose escalation will proceed until a maximum tolerated dose is identified.
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Drug: RP-6306
Oral PKMYT1 Inhibitor Drug: RP-3500 Oral ATR Inhibitor |
- Safety and Tolerability of RP-6306 in patients with advanced solid tumors as assessed by NCI CTCAE v5.0 [ Time Frame: Up to 90 days after last administration of study intervention ]
- To define the MTD of RP-6306 monotherapy, and determine a recommended Phase 2 dose (RP2D) and preferred schedule [ Time Frame: Up to 90 days after last administration of study intervention ]
- Safety and Tolerability of RP-6306 in combination with RP-3500 in patients with advanced solid tumors as assessed by NCI CTCAE v5.0 [ Time Frame: Up to 90 days after last administration of study intervention ]
- To define the MTD of RP-6306 in combination with RP-3500, and determine a recommended Phase 2 dose (RP2D) and preferred schedule [ Time Frame: Up to 90 days after last administration of study intervention ]
- To assess the plasma concentrations of RP-6306 monotherapy in the fasted and fed states. [ Time Frame: through study completion, an average of 1 year ]
- To assess the correlation between RP-6306 dose (mg) and degree of inhibition of phospho-CDK1 signal by immunohistochemistry. [ Time Frame: for the first 3 months on treatment ]
- To assess the percent of patients with a response to RP-6306 monotherapy per RECIST v1.1 criteria. [ Time Frame: Through Study Completion, an average of 1 year ]
- To assess the correlation between RP-6306 and RP-3500 dose (mg) and degree of gamma-H2AX induction by immunohistochemistry. [ Time Frame: for the first 3 months on treatment ]
- To assess the percent of patients with a response to RP-6306 and RP-3500 per RECIST v1.1 criteria. [ Time Frame: Through Study Completion, an average of 1 year ]

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 12 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Male or female and ≥12 years-of-age at the time of informed consent.
- Lansky performance status ≥50% for patients ≤16 years of age, or ECOG score of 0, 1, or 2 for patients >16 years of age.
- Locally advanced or metastatic resistant or refractory solid tumors.
- Patients <18 years of age must weigh at least 40 kg.
- Submission of available tumor tissue at screening or willingness to have a biopsy performed if safe and feasible
- Next generation sequencing (NGS) report obtained in a CLIA-certified or equivalent laboratory demonstrating eligible tumor biomarker.
- Measurable disease as per RECIST v1.1.
- Ability to swallow and retain oral medications.
- Acceptable hematologic and organ function at screening.
- Negative pregnancy test (serum) for women of childbearing potential (WOCBP) at Screening.
- Resolution of all toxicities of prior therapy or surgical procedures.
- Any prior radiation must have been completed at least 7 days prior to the start of study drugs, and patients must have recovered from any acute adverse effects prior to the start of study treatment.
Exclusion Criteria:
- Chemotherapy or small molecule antineoplastic agent given within 21 days or <5 half-lives, whichever is shorter, prior to first dose of study drug.
- History or current condition, therapy, or laboratory abnormality that might confound the study results or interfere with the patient's participation for the full duration of the study treatment.
- Patients who are pregnant or breastfeeding.
- Life-threatening illness, medical condition, active uncontrolled infection, or organ system dysfunction or other reasons which, in the investigator's opinion, could compromise the participating patient's safety.
- Major surgery within 4 weeks prior to first dose of RP-6306.
- Uncontrolled, symptomatic brain metastases.
- Uncontrolled hypertension.
- Psychological, familial, sociological, or geographical conditions that do not permit compliance with the protocol and/or follow-up procedures outlined in the protocol.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04855656
Contact: Jen Truong, MD, MPH | 857-340-5439 | jtruong@reparerx.com |
United States, Connecticut | |
Participating Site # 1012 | Recruiting |
New Haven, Connecticut, United States, 06520 | |
United States, Massachusetts | |
Participating site # 1002 | Recruiting |
Boston, Massachusetts, United States, 02215 | |
United States, Missouri | |
Participating site #1011 | Recruiting |
Saint Louis, Missouri, United States, 63130 | |
United States, New York | |
Participating Site # 1008 | Recruiting |
New York, New York, United States, 10032 | |
Participating Site # 1004 | Recruiting |
New York, New York, United States, 10065 | |
United States, Pennsylvania | |
Participating Site # 1010 | Recruiting |
Philadelphia, Pennsylvania, United States, 19104 | |
Contact PerelmanGyn/OncResearchCoordinatorPool@uphs.upenn.edu | |
United States, Rhode Island | |
Participating Site # 1007 | Recruiting |
Providence, Rhode Island, United States, 02903 | |
United States, Texas | |
Participating Site # 1001 | Recruiting |
Houston, Texas, United States, 77030 | |
United States, Utah | |
Participating Site #1013 | Recruiting |
Salt Lake City, Utah, United States, 84112 | |
Canada, Ontario | |
Participating site # 2002 | Recruiting |
Toronto, Ontario, Canada, M5G 1X8 | |
Participating site #2001 | Recruiting |
Toronto, Ontario, Canada, M5G 2C1 | |
Denmark | |
Participating Site #4001 | Recruiting |
Copenhagen, Denmark |
Responsible Party: | Repare Therapeutics |
ClinicalTrials.gov Identifier: | NCT04855656 |
Other Study ID Numbers: |
RP-6306-01 |
First Posted: | April 22, 2021 Key Record Dates |
Last Update Posted: | May 6, 2023 |
Last Verified: | May 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Neoplasms |