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Advanced Solid TumorPhase 1NCT06232408

LIONS (PLK4 Inhibitor in Advanced Solid Tumors)

A Phase 1 study testing RP-1664 in people with Advanced Solid Tumor, run by Repare Therapeutics at 5 sites in 2 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

The primary objective of this study is to identify a safe and tolerated dose and schedule of the orally administered PLK4 inhibitor RP-1664. In addition, this study will examine the pharmacokinetics (PK), pharmacodynamics (PD) and preliminary anti-tumor activity of RP-1664 in advanced solid tumors. Read more about this study

Who is it for?
Ages 12 to 100 years
Conditions the study is for
Advanced Solid Tumor
What is being tested?
RP-1664
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
29 participants
Where
5 sitesin 2 countries
Study dates
14 Feb 2024to 27 Aug 2025
Phase
Phase 1
Are there results?
Yes, posted in the registrySummary in the doctors' view

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 to 100 years
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • Written informed consent or assent, according to local guidelines, signed and dated by the patient or legal guardian prior to the performance of any study-specific procedures, sampling, or analyses.
  • Male or female and ≥ 12 years-of-age at the time of signature of the consent or assent, and are at least 6th grade reading level to consent; participants < 18 years of age must weigh at least 40 kg.
  • Life expectancy ≥ 4 months.
  • Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1.
  • Locally advanced or metastatic solid tumor that has progressed or was nonresponsive or intolerant to available therapies and for which no standard or available curative therapy exists.
  • Measurable disease as per RECIST v1.1 or INRC.
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  • Existing biomarker profile (tumor tissue or plasma) reported from a local test obtained in a CLIA-certified or equivalent laboratory demonstrating eligible tumor biomarkers.
  • Available tumor tissue.
  • Molecularly eligible tumor profile from a CLIA-certified pathology report.
  • Ability to comply with the protocol and study procedures detailed in the Schedule of Assessments.
  • Ability to swallow and retain oral medications.
  • Acceptable organ function at screening.
  • Acceptable blood counts at screening.
  • Negative pregnancy test (serum or urine) for females of childbearing potential at Screening and while on study drug.
  • Resolution of all toxicities of prior treatment or surgery.
  • Use of highly effective forms of contraception.

Who cannot join

  • History or current condition (such as transfusion dependent anemia or thrombocytopenia), 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.
  • Life-threatening illness, medical condition, active uncontrolled infection, or organ system dysfunction or other reasons which, in the investigator's opinion, could compromise the patient's safety.
  • Uncontrolled, symptomatic brain metastases.
  • Presence of other known second malignancy with the exception of any cancer that has been in complete remission for ≥ 2 years or completely resected squamous and basal cell carcinomas of the skin.
  • Patients with active, uncontrolled bacterial, fungal, or viral infection, including hepatitis B virus (HBV), hepatitis C virus (HCV), known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) related illness.
  • Clinically significant vascular (both arterial and venous) and non-vascular cardiac conditions, active or within 6 months prior to enrollment.
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  • Moderate or severe hepatic impairment (ie, Child-Pugh class B or C).
  • Uncontrolled high blood pressure.
  • Chemotherapy, small molecule or biologic antineoplastic agent given within 21 days.
  • Previously prescribed receptor activator of nuclear factor kappa B ligand (RANKL) inhibitor initiated less than 4 months prior to trial entry. Bisphosphonates are allowed if initiated/administered at least 28 days prior to enrollment.
  • I-131 Meta-Iodo-Benzyl-Guanidine (MIGB) therapy within 6 weeks prior to initiation of trial treatment.
  • Prior treatment with a PLK4 inhibitor.
  • Current treatment with medications that are known to prolong the QT interval.

Trial locations and contacts

5 sites in 2 countries.

5 sites in 2 countries

United States4 sites
  • Participating Site 1012

    New Haven, Connecticut, 06519

  • Participating Site 1008

    New York, New York, 10032

  • Participating Site 1004

    New York, New York, 10065

  • Participating Site 1025

    San Francisco, California, 94143

Other trials in United States

Denmark1 site
  • Participating Site 4001

    Copenhagen

Other trials in Denmark

About this study

Official title: Phase 1 Trial of the Safety, Pharmacokinetics, Pharmacodynamics, and Preliminary Clinical Activity of RP-1664 in Participants With Advanced Solid Tumors

The primary objective of this study is to identify a safe and tolerated dose and schedule of the orally administered PLK4 inhibitor RP-1664. In addition, this study will examine the pharmacokinetics (PK), pharmacodynamics (PD) and preliminary anti-tumor activity of RP-1664 in advanced solid tumors.

Read the detailed description

This is a first-in-human, Phase 1, multi-center, open-label, dose-escalation and expansion study to:

Evaluate the safety profile and MTD of RP-1664 and establish a recommended dose and schedule for further clinical investigation, In addition, the study aims to characterize the PK, PD, and preliminary anti-tumor activity of orally administered RP-1664. Exploratory objectives include examination of biomarker responses in relationship to RP-1664 exposure.

After the recommended dose and schedule is determined, expansion cohorts with molecularly selected advanced solid tumors will be enrolled to preliminarily assess the anti-tumor effect, and further examine the safety and PK of RP-1664 at the RP2D.

Being tested
RP-1664

What participants receive

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

  • RP-1664Drug

    RP-1664 will be supplied as immediate-release solid dosage form for oral self-administration.

Study groups in NCT06232408
Study groupRoleWhat they receive
RP-1664ExperimentalNot described
Receives: Drug: RP-1664

What is being measured

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

  1. Treatment Related Treatment-Emergent Adverse Events (TRAE) With ≥3 CTCAE Grade

    Number of participants with TRAE

    Measured: Start of treatment through up to 6 months post last dose (up to 18 months)

  2. Dose Limiting Toxicities (DLT) to Determine a Maximum Tolerated Dose and Schedule of RP-1664 Based on Safety and Tolerability

    The number of participants with DLTs during the DLT observation period

    Measured: During the first cycle (either 21 or 28 days) following the initiation of the study treatment

Timeline

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

  1. First posted30 Jan 2024
  2. Study start14 Feb 2024
  3. Primary completion27 Aug 2025
  4. Study completion27 Aug 2025

Why it stopped: Sponsor decided to terminate study early

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
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
29 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06232408
Sponsor's protocol ID
RP-1664-01
Status last verified
Nov 2025
First submitted
9 Jan 2024
Last updated
21 Nov 2025
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Vallee F, Casas-Selves M, Bubenik M, Duplessis M, Sow B, Suarez C, Sangiorgi B, Li L, Hyer M, Papp R, Leclaire ME, Perryman AL, Liu B, Surprenant S, Mochirian P, Pau V, Maderova Z, Mader P, Yin SY, Goodfellow E, Roulston A, Stocco R, Godbout C, Baruah P, Bonneau-Fortin A, Schonhoft JD, Nejad P, Norman D, Truong VL, Crane S, Attia MA, Mao D, Sicheri F, Marshall CG, Zimmermann M, Bendahan D, Gallant M, Black WC. Discovery of RP-1664: A First-in-Class Orally Bioavailable, Selective PLK4 Inhibitor. J Med Chem. 2025 Jun 12;68(11):10631-10647. doi: 10.1021/acs.jmedchem.5c00529. Epub 2025 May 16.

    PubMed 40378279

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing RP-1664 in people with Advanced Solid Tumor, run by Repare Therapeutics at 5 sites in 2 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 16 inclusion and 13 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: stopped early, as of the sponsor's last update on 21 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 5 sites in United States, Denmark. 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?

Yes. Results are posted in the registry (first posted 21 Nov 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Treatment Related Treatment-Emergent Adverse Events (TRAE) With ≥3 CTCAE Grade (time frame: Start of treatment through up to 6 months post last dose (up to 18 months)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06232408, which also lists 1 linked publication.

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 21 Nov 2025.

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