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PRT3789 Monotherapy and in Combo w/Docetaxel in Participants w/Advanced or Metastatic Solid Tumors w/SMARCA4 Mutation

A Phase 1 Open-Label, Multi-Center, Safety and Efficacy Study of PRT3789 as Monotherapy and in Combination With Docetaxel in Participants With Advanced or Metastatic Solid Tumors With a SMARCA4 Mutation

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05639751
Enrollment
135
Registered
2022-12-06
Start date
2023-05-02
Completion date
2025-10-01
Last updated
2025-10-16

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

Conditions

Advanced Solid Tumor, Metastatic Solid Tumor, Non-small Cell Lung Cancers, SMARCA4 Gene Mutation

Keywords

Advanced Solid Tumors, BRG1, BRM, Metastatic Solid Tumors, Non-Small Cell Lung Cancers, NSCLC, PRT3789, SMARCA2 Degrader, SMARCA4, Docetaxel

Brief summary

This is a Phase 1 dose-escalation study of PRT3789, a SMARCA2 degrader, in participants with advanced or metastatic solid tumors with loss of SMARCA4 due to truncating mutation and/or deletion. The purpose of this study is to evaluate the safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) of PRT3789 monotherapy and in combination with docetaxel, describe any dose limiting toxicities (DLTs), define the dosing schedule, and to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) to be used in subsequent development of PRT3789.

Detailed description

This is an open-label, multi-center, dose-escalation, first in human, Phase 1 study of PRT3789 as monotherapy and in combination with docetaxel, a SMARCA2 degrader, evaluating participants with advanced or metastatic solid tumors with loss of SMARCA4 due to truncating mutation and/or deletion. The study will evaluate escalating doses of PRT3789 until the MTD or RP2D is determined. Taking into account pharmacokinetic and pharmacodynamic data from the preceding dose levels, the dose may be escalated until a dose limiting toxicity is identified. Approximately 186 participants will be enrolled in monotherapy, dose escalation, backfill, and combination cohorts.

Interventions

PRT3789 will be administered by intravenous infusion

DRUGDocetaxel

Docetaxel will be administered by intravenous infusion

Sponsors

Prelude Therapeutics
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

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

Inclusion criteria

* Willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations (including contraception requirements), and other study procedures * Histologically confirmed advanced, recurrent, or metastatic solid tumor malignancy with any mutation of SMARCA4 (dose escalation and combination cohorts) and loss of function mutation of SMARCA4 (backfill cohorts) by local testing that have either progress on or ineligible for standard of care therapy * Must have measurable or non-measureable (but evaluable) disease per RECIST v1.1 for dose escalation and combination cohorts * Must have measureable diseases per RECIST v1.1 for backfill cohort * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 * Willing to provide either archival or fresh tumor tissue sample * Adequate organ function (hematology, renal, and hepatic)

Exclusion criteria

* Participants with solid tumors with known concomitant SMARCA2 mutation or loss of protein expression * Clinically significant or uncontrolled cardiac disease, uncontrolled electrolyte disorders, uncontrolled or symptomatic central nervous system (CNS) metastases or leptomeningeal disease * History of another malignancy within 3 years except for adequately treated basal cell or squamous cell skin cancer, superficial bladder cancer, prostate intraepithelial neoplasm, carcinoma in situ of the cervix, or other noninvasive or indolent malignancies, or malignancies previously treated with curative intent and not on active therapy or expected to require treatment or recurrence during the study * Concurrent treatment with strong or moderate CYP3A4 inhibitor or inducer

Design outcomes

Primary

MeasureTime frameDescription
Dose limiting toxicity (DLT) of PRT3789 monotherapy and in combination with docetaxelBaseline through Day 21Dose limiting toxicities will be evaluated over the 21-day observation period
Safety and tolerability of PRT3789 monotherapy and in combination with docetaxel: AEs, CTCAE AssessmentsBaseline through approximately 3 yearsSafety and tolerability will be evaluated by incidence of DLTs, laboratory measurements, dose interruption, modification, and discontinuation due to adverse events (AEs) according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE)
Maximum tolerated dose (MTD)/ Recommended phase 2 dose (RP2D) of PRT3789 monotherapy and in combination with docetaxelBaseline through approximately 3 yearsThe MTD/RP2D will be established for further investigation in participants with advanced solid tumors

Secondary

MeasureTime frameDescription
Efficacy of PRT3789 monotherapy and in combination with docetaxel: Duration of response (DOR)Baseline through approximately 3 yearsDuration from time of first observed response (CR or PR) to the earliest date of disease progression, as assessed by the investigator per RECIST v1.1, or death due to any cause
Pharmacokinetic profile of PRT3789 monotherapy and in combination with docetaxel: Maximum observed plasma concentrationBaseline through approximately 3 yearsPharmacokinetics will be calculated including the maximum observed plasma concentration
Efficacy of PRT3789 monotherapy and in combination with docetaxel: Objective response rate (ORR)Baseline through approximately 3 yearsBest overall response of either complete response (CR) or partial response (PR), as assessed by the investigator per RECIST v1.1
Pharmacodynamic effect of PRT3789 monotherapy and in combination with docetaxel: Target engagementBaseline through approximately 3 yearsPharmacodynamic effect of PRT3789 monotherapy and in combination with docetaxel demonstrating target engagement by assessment of SMARCA2 protein in peripheral blood mononuclear cells (PBMCs) and tumor tissue
Pharmacokinetic profile of PRT3789 monotherapy and in combination with docetaxel: Area under the curveBaseline through approximately 3 yearsPharmacokinetics will be calculated including the area under the plasma concentration versus time curve (AUC)
Efficacy of PRT3789 monotherapy and in combination with docetaxel: Progression-free survival (PFS)Baseline through approximately 3 yearsDuration from Day 1 to the earliest date of first disease progression, as assessed by the investigator per RECIST v1.1, discontinuation because of disease progression, or death due to any cause
Efficacy of PRT3789 monotherapy and in combination with docetaxel: Clinical benefit rate (CBR)Baseline through approximately 3 yearsBest overall response of CR, PR, or durable stable disease (24 weeks or longer duration), as assessed by the investigator per RECIST v1.1

Countries

France, Netherlands, Singapore, Spain, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 7, 2026