A Study to Evaluate the Safety, Tolerability and Preliminary Efficacy of LRK-4189 Alone and in Combination in Patients With Solid Tumors

March 23, 2026 updated by: LARKSPUR BIOSCIENCES, INC.

A Phase 1b-2, Open-Label, Dose-Escalation, Expansion and Optimization Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Efficacy of LRK-4189 Alone and in Combination With mFOLFOX6 or FOLFIRI in Patients With Solid Tumors

The goal of this clinical trial is to learn if investigational agent LRK-4189 works to treat solid tumors in adults, with a focus on colorectal cancer. It will also learn about the safety of drug LRK-4189.

The main questions it aims to answer are:

Is LRK-4189, administered alone or in combination with standard chemotherapy regimens, safe and tolerable in patients with solid tumors?

Participants will:

  • Take investigational agent LRK-4189 alone or in combination with standard chemotherapy regimens every day for up to 3 years.
  • Visit the clinic once every week for checkups and tests.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Willing and able to sign the study consent form and take part in all required study visits, tests, and procedures.
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.
  • Have a locally advanced or metastatic cancer that cannot be removed with surgery and has gotten worse despite treatment.
  • Cancer can be measured on scans, such as CT or MRI.
  • Willing to have tumor biopsies, meaning small samples of your tumor will be collected during the study.
  • Heart rhythm test (ECG) shows a normal result within safe limits.
  • Blood test results at screening are within an acceptable and stable range.
  • If you are a woman, you are not able to become pregnant, or you agree not to become pregnant during the study and to use approved birth control methods.
  • If you are a man, you agree not to donate sperm during the study. If you have sex with a partner who could become pregnant, you agree to use approved birth control methods during the study.

Exclusion Criteria:

  • Unable to swallow the study medication or your body cannot absorb it.
  • Have had a serious allergic reaction to LRK-4189 or any of its ingredients.
  • Have needed a fluid drainage procedure from the chest or abdomen within the past 6 weeks.
  • Have active cancer in the brain or spinal fluid, or brain tumors that require steroid treatment.
  • Currently receiving another cancer treatment.
  • Have an active HIV, hepatitis B, or hepatitis C infection with detectable virus levels.
  • Have an active infection that requires treatment through a vein (IV).
  • Taking certain medications that strongly interact with the study drug and cannot stop them at least 14 days before starting the study.
  • Pregnant or breastfeeding or planning to become pregnant or father a child during the study.
  • Cannot safely receive the standard chemotherapy that would be used with this study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Part 1/1b escalation
Drug: LRK-4189 escalation
LRK-4189 at various doses
Experimental: Part 2 expansion
Drug: LRK-4189 expansion
LRK-4189 MTD
Experimental: Part 2b expansion
Drug: LRK-4189 expansion
LRK-4189 MTD
Drug: Chemo
Standard of care
Experimental: Part 3 optimization
Drug: LRK-4189 optimization
LRK-4189 2 distinct doses

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Evaluation of treatment-related adverse events and/or toxicity, presented by dose, regimen and tumor type
Time Frame: From enrollment to the end of the first treatment cycle (each cycle is 21 days)
From enrollment to the end of the first treatment cycle (each cycle is 21 days)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

LARKSPUR BIOSCIENCES, INC.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 1, 2026

Primary Completion (Estimated)

June 1, 2029

Study Completion (Estimated)

June 1, 2029

Study Registration Dates

First Submitted

March 18, 2026

First Submitted That Met QC Criteria

March 23, 2026

First Posted (Actual)

March 27, 2026

Study Record Updates

Last Update Posted (Actual)

March 27, 2026

Last Update Submitted That Met QC Criteria

March 23, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • LRK-4189-102

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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