A Trial of RSC-1255 for Treatment of Patients With Advanced Malignancies

March 17, 2026 updated by: RasCal Therapeutics, Inc.

A Phase Ia/Ib, Open Label, Multi-center, Non-randomized Dose Escalation and Dose Expansion Study of RSC-1255 Alone or in Combination With Hydroxychloroquine in Patients With Advanced Solid Tumor Malignancies

RSC-101 is a Phase 1a/1b clinical trial of RSC-1255 in adult study participants with advanced solid tumor malignancies who are intolerant of existing therapies known to provide clinical benefit, have disease that has progressed after standard therapy, or have previously failed other therapies. The study has two phases. The purpose of Phase 1a (Dose Escalation) is to confirm the appropriate treatment dose and Phase 1b (Dose Expansion) is to characterize the safety and efficacy of RSC-1255.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

RSC-1255 is an orally bioavailable, small-molecule direct pan-mutant and wild-type RAS inhibitor. RSC-101 is a Phase 1a/1b, open-label, multi-center, non-randomized, Dose Escalation and Dose Expansion study in participants with advanced solid tumor malignancies. Study enrollment is approximately 134 participants. All participants receive oral RSC-1255, twice daily as monotherapy. Following Phase 1a (Dose Escalation) to identify the Maximum Tolerated Dose and Recommended Dose for use in Phase 1b, additional participants are enrolled in the Phase 1b (Dose Expansion) to further characterize the safety, pharmacology, and the clinical efficacy of RSC-1255 as monotherapy and in combination with the autophagy inhibitor hydroxychloroquine (HCQ).

Study Type

Interventional

Enrollment (Estimated)

134

Phase

  • 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

  • United States
    • California
      • Los Angeles, California, United States, 90404
        • Recruiting
        • University of California, Los Angeles (UCLA) Department of Medicine - Hematology/Oncology
    • Colorado
      • Denver, Colorado, United States, 80218
        • Recruiting
        • Sarah Cannon, SCRI Oncology Partners - Health One
    • Tennessee
      • Nashville, Tennessee, United States, 37203
        • Recruiting
        • Sarah Cannon, SCRI Oncology Partners

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

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria (Key Factors):

  1. Has pathologically confirmed advanced or metastatic malignancy characterized by one or more of the following:

    • Participant is intolerant of existing therapy(ies) known to provide clinical benefit for their condition
    • Malignancy is refractory to existing therapy(ies) known to potentially provide clinical benefit
    • Malignancy has progressed on standard therapy
  2. Has evaluable or measurable tumor(s) in dose-escalation by standard radiological and/or laboratory assessments as applicable to their malignancy.
  3. Has adequate performance status (PS): Eastern Co-operative Oncology Group (ECOG).
  4. Is age ≥ 18 years.
  5. Has either tissue agnostic tumors and documented RAS mutations or with glioblastoma with or without mutation in RAS

Exclusion Criteria (Key Factors):

  1. Participants receiving cancer therapy at the time of enrollment.
  2. Any clinically significant disease or condition affecting a major organ system.
  3. Significant cardiovascular disease or electrocardiogram (ECG) abnormalities.
  4. Known Gilbert's disease.
  5. Has had a previous (within 2 years) or has a current malignancy other than the target cancer.
  6. Intermittent hypokalemia
  7. Grade 1 or higher nausea, vomiting, diarrhea at baseline due to underlying disease

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: N/A
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: RSC-1255 Treatment
Single Arm Study. All study participants receive RSC-1255.
Drug: RSC-1255 Dose Escalation
Phase 1a will enroll 40-80 participants to identify the dose limiting toxicity (DLT), recommended Phase 1b dose, and the safety and tolerability of RSC-1255. RSC-1255 is administered orally twice daily, with and without food. Each cycle is 21 days.
Other Names:
  • Phase 1a
  • Dose Escalation
Drug: RSC-1255 Dose Expansion
Phase 1b will enroll 48-94 participants to further characterize the safety, pharmacology, and clinical efficacy of RSC-1255. RSC-1255 is administered orally twice daily alone or in combination with continuous hydroxychloroquine, with food. Each cycle is 21 days.
Other Names:
  • Phase 1b
  • Dose Expansion

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximum Tolerated Dose (MTD) for RSC-1255 as monotherapy
Time Frame: Approximately 30 months
The number and type of dose-limiting toxicities (DLTs) as defined in the protocol that occur during the first 21 days of treatment and maximum grade of all treatment-related events using CTCAE V5.0 will be used to identify a safe and tolerable dose.
Approximately 30 months
Recommended Phase 2 Dose (RP2D) for RSC-1255 as monotherapy
Time Frame: Approximately 12 months
The number and type of DLTs as defined in the protocol that occur during the first 21 days of treatment and maximum grade of all treatment-related adverse events using CTCAE 5.0 will be used to identify a safe and tolerable dose.
Approximately 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Adverse event profile of RSC-1255
Time Frame: Approximately 24 months
Toxicities will be graded according to CTCAE V5.0.
Approximately 24 months
Overall Survival (OS)
Time Frame: Approximately 24 months
Overall Survival
Approximately 24 months
Disease Progression
Time Frame: Approximately 24 months
Disease Progression will be assessed using RECIST V1.1
Approximately 24 months

Collaborators and Investigators

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

Sponsor

RasCal Therapeutics, Inc.

Investigators

  • Study Director: Michael Mann, MD, RasCal Therapeutics, 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 (Actual)

March 3, 2021

Primary Completion (Estimated)

December 15, 2026

Study Completion (Estimated)

January 30, 2027

Study Registration Dates

First Submitted

December 8, 2020

First Submitted That Met QC Criteria

December 16, 2020

First Posted (Actual)

December 22, 2020

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 17, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RSC-101

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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