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Advanced Solid TumorPhase 1MYTHICNCT04855656

Study of Lunresertib Alone or in Combination With RP-3500 or Zedoresertib (Debio 0123) in Patients With Advanced Solid Tumors

A Phase 1 study testing Lunresertib, RP-3500 and Zedoresertib in people with Advanced Solid Tumor, run by Debiopharm International SA at 26 sites in 5 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

The primary purpose of this study is to assess the safety and tolerability of lunresertib alone and in combination with RP-3500 or in combination with zedoresertib in patients with eligible advanced solid tumors, determine the maximum tolerated dose (MTD) and assess preliminary anti-tumor activity. Read more about this study

Who is it for?
Ages 12 years and older
Conditions the study is for
Advanced Solid Tumor
What is being tested?
Lunresertib, RP-3500 and Zedoresertib
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
464 participants
Where
26 sitesin 5 countries
Study dates
30 Apr 2021to Jun 2028
Phase
Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 12 years and older
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • 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 module 1) 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.
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  • CCNE1 amplification (non-equivocal) as determined by either a tumor or plasma NGS test, or FISH
  • FBXW7 deleterious mutations identified by either a tumor or plasma NGS test
  • PPP2R1A deleterious mutations identified by either a tumor or plasma NGS test
  • Measurable disease as per RECIST v1.1. For certain modules, patients with prostate cancer or ovarian cancer that have non-measurable disease but have elevated tumor markers (PSA or CA-125, respectively) can also be eligible
  • 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.

Who cannot join

  • 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 lunresertib.
  • Uncontrolled, symptomatic brain metastases.
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  • Uncontrolled hypertension.
  • Certain prior anti-cancer therapy
  • Psychological, familial, sociological, or geographical conditions that do not permit compliance with the protocol and/or follow-up procedures outlined in the protocol.

Trial locations and contacts

26 sites in 5 countries. Contact the study team or a site near you to ask about taking part.

Debiopharm International S.A contact

+41 21 321 01 11

clinicaltrials@debiopharm.com

26 sites in 5 countries

United States17 sites, 14 recruiting
  • #1002, Dana Farber Cancer Institute

    Boston, Massachusetts, 02215

    Recruiting
  • #1027, University of Virginia

    Charlottesville, Virginia, 22903

    Recruiting
  • #1023, START Midwest

    Grand Rapids, Michigan, 49503

    Recruiting
  • #1001, The University of Texas M.D. Anderson Cancer Center

    Houston, Texas, 77030

    Recruiting
  • #1017, Mayo Clinic

    Jacksonville, Florida, 32224

    Recruiting
  • # 1019, UCLA, Westwood Cancer Center

    Los Angeles, California, 90095

    Completed
  • #1012, Yale

    New Haven, Connecticut, 06520

    Recruiting
  • #1032, Northwell Health Cancer Institute

    New Hyde Park, New York, 11042

    Recruiting
  • #1008, Columbia University

    New York, New York, 10032

    Completed
  • #1004, Memorial Sloan Kettering Cancer Institute

    New York, New York, 10065

    Recruiting
  • #1010, University of Pennsylvania

    Philadelphia, Pennsylvania, 19104

    Completed
  • #1007, Rhode Island Hospital

    Providence, Rhode Island, 02903

    Recruiting
  • #1030, Women & Infants Hospital of Rhode Island

    Providence, Rhode Island, 02903

    Recruiting
  • #1016, Mayo Clinic

    Rochester, Minnesota, 55902

    Recruiting
  • #1013, The University of Utah

    Salt Lake City, Utah, 84112

    Recruiting
  • #1025, University of California San Francisco

    San Francisco, California, 94158

    Recruiting
  • #1011, Washington University

    St Louis, Missouri, 63130

    Recruiting

Other trials in United States

Spain4 sites, 4 recruiting
  • Clinica Universidad de Navarra

    Madrid, 28027

    Not yet recruiting
  • START Madrid. Hospital Fundación Jimenez Diaz

    Madrid, 28040

    Recruiting
  • Hospital Universitario HM Sanchinarro

    Madrid, 28050

    Recruiting
  • Clinica Universidad de Navarra

    Navarra, 31008

    Not yet recruiting

Other trials in Spain

Canada3 sites, 1 recruiting
  • #2003, The Research Institute of the McGill University Health Centre

    Montreal, Quebec, H4A 3J1

    Completed
  • #2002, The Hospital for Sick Children

    Toronto, Ontario, M5G 1X8

    Completed
  • #2001, Princess Margaret Cancer Centre

    Toronto, Ontario, M5G 2C1

    Recruiting

Other trials in Canada

Denmark1 site, 1 recruiting
  • #4001, Rigshospitalet - Blegdamsvej

    Copenhagen

    Recruiting

Other trials in Denmark

United Kingdom1 site, 1 recruiting
  • #3003, Sarah Cannon Research Institute

    London, W1G 6AD

    Recruiting

Other trials in United Kingdom

About this study

Official title: Phase 1/1b Study of the Safety, Pharmacokinetics, Pharmacodynamics and Preliminary Clinical Activity of Lunresertib Alone or in Combination With RP-3500 or Debio 0123 in Patients With Advanced Solid Tumors

The primary purpose of this study is to assess the safety and tolerability of lunresertib alone and in combination with RP-3500 or in combination with zedoresertib in patients with eligible advanced solid tumors, determine the maximum tolerated dose (MTD) and assess preliminary anti-tumor activity.

Read the detailed description

Phase 1/1b, multi-center, open-label, dose-escalation study to:

  • Evaluate the safety profile and MTD of lunresertib alone and in combination with RP-3500 or in combination with zedoresertib when administered orally to establish the recommended Phase 2 dose and schedule
  • Characterize the PK and pharmacodynamics of lunresertib alone and in combination with RP-3500 or in combination with zedoresertib
  • Assess preliminary anti-tumor activity associated with lunresertib alone and in combination with RP-3500 or in combination with zedoresertib

This study was previously posted by Repare Therapeutics. In September 2025, sponsorship of the trial was transferred to Debiopharm International S.A

Expanded Access Status: There is no expanded access program available for the investigational products in this study at this time.

Being tested
Lunresertib, RP-3500, Zedoresertib

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • LunresertibDrug

    Oral PKMYT1 Inhibitor

  • RP-3500Drug

    Oral ATR Inhibitor

  • ZedoresertibDrug

    Also called Debio 0123

    Oral WEE1 Inhibitor

Study groups in NCT04855656
Study groupRoleWhat they receive
Phase 1: Lunresertib Single-Agent, Dose Escalation and Food-effect StudyExperimentalPatients receive lunresertib orally until disease progression, unacceptable toxicity, or investigator/patient decision. Dose escalation will proceed until a maximum tolerated dose is identified.
Receives: Drug: Lunresertib
Phase 1: Lunresertib in combination with RP-3500, Dose Escalation StudyExperimentalPatients receive lunresertib with RP-3500 orally until disease progression, unacceptable toxicity, or investigator/patient decision. Dose escalation will proceed until a maximum tolerated dose is identified.
Receives: Drug: Lunresertib; Drug: RP-3500
Phase 1: Lunresertib in combination with Zedoresertib, Dose Escalation StudyExperimentalPatients receive lunresertib with zedoresertib orally until disease progression, unacceptable toxicity, or investigator/patient decision. Dose escalation will proceed until a maximum tolerated dose is identified.
Receives: Drug: Lunresertib; Drug: Zedoresertib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Safety and Tolerability of lunresertib either in monotherapy or in combination with RP-3500 or with Zedoresertib in patients with eligible advanced solid tumors

    Assessed by treatment-emergent adverse events (TEAEs), physical examinations (PEs), safety laboratory assessments, electrocardiograms (ECGs), and vital sign measurements

    Measured: Up to 90 days after last administration of study intervention

  2. To define the MTD of lunresertib monotherapy, and determine a recommended Phase 2 dose (RP2D) and preferred schedule

    Assessed by the incidence of Dose-limiting toxicities (DLTs) and the incidence and severity of cumulative safety data

    Measured: Up to 90 days after last administration of study intervention

  3. To define the MTD of lunresertib in combination with RP-3500 or in combination with Zedoresertib, and determine a recommended Phase 2 dose (RP2D) and preferred schedule

    Assessed by the incidence of dose-limiting toxicities (DLTs) and the incidence and severity of cumulative safety data

    Measured: Up to 90 days after last administration of study intervention

  4. The relative bioavailability of lunresertib capsule formulation as compared to lunresertib tablet formulation in the fasted state

    Assessed by the plasma concentrations of lunresertib with calculation of pharmacokinetic (PK) parameters including maximum observed plasma concentration (Cmax), time to maximum observed plasma concentration (Tmax), area under the plasma concentration-time curve (AUC) , for both formulations in the fasted state.

    Measured: Time 0 (time of dosing) to 72 hours post-dose for each treatment condition

  5. The effect of food on the PK of tablet formulation of lunresertib when administered in fed conditions compared to administration under fasted conditions

    Assessed by the plasma concentrations of lunresertib with calculation of the ratio of PK parameters (e.g., Cmax and AUC) between the tablet formulation under fasted and fed state.

    Measured: Time 0 (time of dosing) to 72 hours post-dose for each treatment condition

  6. To assess the safety and tolerability of lunresertib tablets in combination with RP-3500, confirm the MTD of lunresertib tablets in combination with RP-3500, and determine a RP2D and preferred schedule

    Assessed by DLTs, TEAEs, safety laboratory assessments, the incidence of DLTs and the incidence and severity of cumulative safety data

    Measured: Up to 90 days after last administration of study intervention

Secondary outcomes (6)
  1. The plasma concentrations of lunresertib monotherapy (capsule formulation) in the fasted and fed states

    Assessed by the plasma concentrations of lunresertib with calculation of maximum observed plasma concentration (Cmax), time to maximum observed plasma concentration (Tmax), minimum observed plasma concentration (Cmin), area under the plasma concentration-time curve (AUC), elimination half-life (t1/2), and other parameters as appropriate

    Measured: Up to 90 days after last administration of study intervention

  2. To assess the relationship between pharmacodynamic biomarkers and PK of lunresertib at different dose levels and/or schedules

    Assessed by evaluation of biomarkers in pre- and on-treatment biopsies, and circulating tumor DNA (ctDNA) dynamics during treatment

    Measured: Up to 90 days after last administration of study intervention

  3. The plasma concentrations of lunresertib and RP-3500 when dosed in combination

    Assessed by the plasma concentrations of lunresertib and RP-3500 with calculation of maximum observed plasma concentration (Cmax), time to maximum observed plasma concentration (Tmax), minimum observed plasma concentration (Cmin), area under the plasma concentration-time curve (AUC), elimination half-life (t1/2), and other parameters as appropriate for each analyte

    Measured: Up to 90 days after last administration of study intervention

  4. To assess preliminary anti-tumor activity achieved with lunresertib monotherapy, lunresertib in combination with RP-3500 or lunresertib in combination with Zedoresertib

    Measured by best percent change in tumor size from baseline, objective response rate (ORR), overall response rate, tumor marker response, duration of response (DOR), clinical benefit rate (CBR), progression-free survival (PFS).

    Measured: Through Study Completion, an average of 1 year

  5. To assess the safety and anti-tumor effects of lunresertib capsule + RP-3500

    As measure by TEAEs, safety laboratory assessments, Best percent change in tumor size from baseline, ORR, overall response rate, DOR, CBR, tumor marker response, PFS

    Measured: Through Study Completion, an average of 1 year

  6. To further characterize the PK of lunresertib tablets and assess preliminary anti-tumor

    Measured by Plasma concentrations of lunresertib with calculation of Cmax, Tmax, AUC, elimination t1/2, and other PK parameters as appropriate, Best percent change in tumor size from baseline, ORR, overall response rate, DOR, CBR, tumor marker response, PFS

    Measured: Through Study Completion, an average of 1 year

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted22 Apr 2021
  2. Study start30 Apr 2021
  3. Primary completionDec 2027 (estimated)
  4. Study completionJun 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Single group
Masking
None (open label)
Enrolment
464 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04855656
Sponsor's protocol ID
Debio 0123-106
Other IDs
RP-6306-01
Acronym
MYTHIC
Status last verified
Oct 2026
First submitted
9 Apr 2021
Last updated
28 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Lunresertib, RP-3500 and Zedoresertib in people with Advanced Solid Tumor, run by Debiopharm International SA at 26 sites in 5 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 15 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 26 sites in United States, Spain, Canada, Denmark, United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Debiopharm International S.A (+41 21 321 01 11, clinicaltrials@debiopharm.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Safety and Tolerability of lunresertib either in monotherapy or in combination with RP-3500 or with Zedoresertib in patients with eligible advanced solid tumors (time frame: Up to 90 days after last administration of study intervention). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.

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