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Safety and Preliminary Efficacy of SA53-OS in Patients With Locally Advanced or Metastatic Solid Tumors

A Phase 1/2a, Open-Label Study of Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of SA53-OS, an MDM2 Inhibitor, in Patients With Locally Advanced or Metastatic p53 Wild-Type Solid Tumors

Status
Recruiting
Phases
Phase 1Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06578624
Enrollment
70
Registered
2024-08-29
Start date
2025-03-10
Completion date
2028-12-01
Last updated
2026-09-09

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Solid Tumor

Keywords

p53 wild-type tumor, liposarcoma, MDM2 inhibitor, solid tumors, dedifferentiated liposarcoma (DD LPS), p53, Advanced or metastatic solid tumors

Brief summary

The objective of this study is to assess the safety, efficacy, and pharmacokinetics of SA53-OS in adult participants with refractory solid tumors. The study is comprised of 2 parts: Part 1 called dose escalation, and Part 2a called dose expansion. This study starts with Part 1 where participants who are diagnosed with advanced or metastatic solid tumor cancers receive different doses of SA53-OS (starting with the lowest dose) to find the maximum tolerated dose (MTD) of SA53-OS. Once the MTD of SA53-OS is known, the study continues to Part 2a where participants who are diagnosed with dedifferentiated liposarcoma (DD LPS) or other solid tumor cancers will receive SA53-OS at the MTD. The study drug, SA53-OS, will be administered for 3 consecutive days every 3 weeks as an oral solution for up to 2 years.

Detailed description

This is a phase 1/2a, open-label, dose escalation study conducted in adult participants with p53 wild-type refractory solid tumors. The study will assess the safety, efficacy, and pharmacokinetics of SA53-OS a novel MDM2 inhibitor capable of selective activation of p53. This enables the p53 tumor suppressor protein to selectively facilitate tumor cell death and growth inhibition. The study drug, SA53-OS, will be administered for 3 consecutive days every 3 weeks as an oral solution. Phase 1 will consist of a dose escalation study to establish a candidate recommended phase 2 dose (RP2D). Phase 2a will enroll 2 expansion cohorts to establish any preliminary efficacy of SA53-OS in participants with dedifferentiated liposarcoma (DD LPS) with MDM2 amplifications and other p53 wild-type solid tumors as a single agent. Phase 1 dose escalation: Escalating doses of SA53-OS will be provided to participants with p53 wild-type refractory solid tumors to determine the RP2D. The MTD is the highest dose of a drug or treatment that does not cause unacceptable side effects in the first cycle. The RP2D considers all available safety, pharmacokinetics, and efficacy data including, the frequency, severity, and manageability of toxicities occurring after Cycle 1. Phase 1 of the study will start with dose escalation by 2-fold (i.e., 2x preceding dose level) in cohorts of a single participant until Grade 2 or greater toxicity is observed. When a single Grade 2 or higher toxicity is observed, 3+3 multi-participant cohorts will be treated at the dose in which the Grade 2 or higher toxicity was observed by enrolling another 2 participants at this dose. The 3+3 multi-participant cohorts will follow the standard 3+3 paradigm based on occurrence of any DLT with 50% dose escalation until the MTD is identified. Phase 2a dose expansion: The purpose of Phase 2a of the study is to describe any preliminary evidence of efficacy from SA53-OS monotherapy in participants with DD LPS or other p53 wild-type or MDM2 amplified solid tumors. Phase 2a will also be used to confirm the safety and tolerability of the candidate RP2D of SA53-OS determined in Phase 1 of the study, to further describe the toxicity and pharmacokinetics profiles of SA53-OS, and to assess potential biomarkers of sensitivity resistance, and toxicity. Participants will continue to receive study treatment until either: 1) disease progression; 2) occurrence of unacceptable treatment-related toxicity as per participant or Investigator discretion; 3) the maximum of 2 years of treatment has been reached; or 4) other reason(s) for study treatment discontinuation. In the case of complete response, treatment should be continued for at least 6 months if no other stopping criteria are met, and further treatment can be recommended at the investigator's discretion.

Interventions

DRUGSA53-OS (phase 1)

Dose escalation phase in which participants receive SA53-OS on 3 consecutive days every 3 weeks for a maximum of 2 years. Single participant cohorts will be enrolled until a Grade 2 or greater toxicity is observed and then 3+3 multi-participant cohorts will be enrolled until the MTD is identified.

DRUGSA53-OS (phase 2)

Dose expansion phase in which participants receive SA53-OS on 3 consecutive days every 3 weeks for a maximum of 2 years at the MTD identified in phase 1.

Sponsors

Lamassu Bio Inc
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

Phase 1 of the study will start with dose escalation by 2-fold (i.e., 2x preceding dose level) in cohorts of a single participant until Grade 2 or greater toxicity is observed. When a single Grade 2 or higher toxicity is observed, 3+3 multi-participant cohorts will be treated at the dose in which the Grade 2 or higher toxicity was observed by enrolling another 2 participants at this dose. The 3+3 multi-participant cohorts will follow the standard 3+3 paradigm based on occurrence of any DLT with 50% dose escalation until the MTD is identified. In phase 2 of the study, the MTD will be administered to 2 cohorts of 20 participants each: Cohort A) with known MDM2 amplified DD LPS; Cohort B) p53 wild-type solid tumors.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Tumor characteristics of participants in Phase 1 1. Histologically and/or cytologically confirmed diagnosis of advanced or metastatic solid tumor and/or non-Hodgkin lymphoma excluding primary central nervous system malignancy for which no standard effective treatment exists or where that treatment was declined. Participants with non-Hodgkin lymphoma should have failed ≥ 2 prior lines of systemic therapy prior enrollment. 2. Tumor p53 wild-type. * Tumor characteristics of participants in Phase 2a 1. Cohort A: Tumor p53 wild-type with histologically confirmed diagnosis of advanced or metastatic DD LPS (and MDM2 amplification); OR Cohort B: Tumor p53 wild-type in other solid tumor. 2. Measurable disease by RECIST 1.1. * 18 years old or older. * Resolution of clinically relevant toxicity-related to prior anticancer therapies prior to receipt of study treatment to Grade 1 or less. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Participants of childbearing/reproductive potential must agree to use adequate birth control measures during the course of the trial and for at least 3 months after discontinuing study treatment.

Exclusion criteria

* Anticipated need for major surgery and/or localized palliative radiation within the next 6 weeks * Active, untreated central nervous system metastases. Participants with brain metastases identified at Screening may be rescreened after the lesion(s) have been appropriately treated; participants with treated brain metastases should be neurologically stable for 4 weeks post-treatment and prior to study enrollment, and off corticosteroids for at least 2 weeks before start of study treatment, and treated lesions should demonstrate no new growth on the re-screening scan. * Known HIV infection or active hepatitis B or C infection. * Thrombotic event requiring active and ongoing anticoagulation within the last 6 months prior to study treatment. * Myocardial infarction within the last 6 months prior to study treatment. * Significant cardiovascular disease including unstable angina pectoris, uncontrolled hypertension or arrhythmia, congestive heart failure New York Heart Association (NYHA) Class III or IV related to primary cardiac disease, uncontrolled ischemic or severe vascular heart disease. * A history of additional risk factors for Torsades de Pointes (TdP) (e.g., heart failure, hypokalemia, family history of Long QT Syndrome) * Known bleeding disorder (e.g., hemophilia, von Willebrand disease). * Conditions that may predispose to major bleeding (e.g., active GI ulcers, upper or lower GI bleedings in the last 6 months, significant hemoptysis in the last 6 months, tumor invasion of major vessels, etc.). Conditions that have been treated may be allowed if resolution of the risk is documented. * Use or indication for full dose anticoagulation or anti-platelet therapy including low dose aspirin. * Women who are pregnant or lactating.

Design outcomes

Primary

MeasureTime frameDescription
Phase 1: Incidence of DLT21 daysIncidence of DLT in Cycle 1 (Day 1 to 21)
Phase 1 and 2: Adverse eventsApproximately 2 yearsFrequency of adverse events

Secondary

MeasureTime frameDescription
Phase 2: Progression free survival (PFS)Approximately 2 yearsParticipants not meeting the definition for progressive disease
Phase 2: Overall survivalApproximately 2 yearsTo evaluate overall survival
Phase 2: Duration of responseApproximately 2 yearsDuration of response will be evaluated in responders
Phase 2: Complete response rateApproximately 2 yearsParticipants achieving CR defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to \<10 mm.
Phase 1: Peak plasma concentrationDay 4Determine the pharmacokinetic profile of SA53-OS (Cmax)
Phase 1: Area under the plasma concentration versus time curve between 0 and 24 hoursDay 4Determine the pharmacokinetic profile of SA53-OS (AUC0-24)
Phase 1: Half-lifeDay 4Determine the pharmacokinetic profile of SA53-OS (T1/2)
Phase 2: Stable disease rateApproximately 2 yearsParticipants achieving stable disease defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease.
Phase 2: Objective response rate (ORR)Approximately 2 yearsParticipants achieving ORR defined as complete response (CR) rate plus partial response (PR) rate. CR: Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to \<10 mm. PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
Phase 2: Disease control rateApproximately 2 yearsParticipants achieving CR + PR + stable disease

Countries

United States

Contacts

CONTACTJill Palmenberg
jill.palmenberg@lamassubio.com520-241-5944
STUDY_DIRECTORGabi Hanna, MD

Lamassu Bio

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 10, 2026