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A Study of PRT3645 in Participants With Select Advanced or Metastatic Solid Tumors

A Phase 1 Open-Label, Multi-Center, Safety and Efficacy Study of PRT3645 in Participants With Select Advanced or Metastatic Solid Tumors

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05538572
Enrollment
22
Registered
2022-09-14
Start date
2022-12-27
Completion date
2024-06-26
Last updated
2024-07-01

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

Conditions

Breast Cancer, Endometrial Cancer, Glioblastoma, Head and Neck Squamous Cell Carcinoma, Malignant Mesothelioma, Non-small Cell Lung Cancers, Sarcoma

Keywords

Advanced Solid Tumors, Breast Cancer, CDK4/6, Cyclin-dependent Kinase 4, Cyclin-dependent Kinase 6, Glioblastoma, Head and Neck Squamous Cell Carcinoma, HNSCC, Malignant Mesothelioma, Metastatic Solid Tumors, Non-small Cell Lung Cancers, NSCLC, PRT3645, Sarcoma, Endometrial Cancer

Brief summary

This is a Phase 1 dose-escalation study of PRT3645, a Cyclin-dependent Kinase 4/6 (CDK4/6) inhibitor, in patients with advanced or metastatic solid tumors. The purpose of this study is to investigate the safety, tolerability, dose limiting toxicity, and to determine maximally tolerated dose and recommended phase 2 dose to be used in subsequent development of PRT3645.

Detailed description

This is an open-label, multicenter, dose-escalation Phase 1 study of PRT3645, a CDK4/6 inhibitor, evaluating patients with selected advanced or metastatic solid tumors including breast cancer (BC), glioblastoma (GBM), non-small cell lung cancer (NSCLC), sarcomas, head and neck squamous cell carcinoma (HNSCC), malignant mesothelioma, and endometrial cancer. The study plan expects to evaluate approximately eight dose levels however additional dose levels may be explored. Taking into account pharmacokinetic and pharmacodynamic data from the preceding dose levels, the dose may be escalated until a dose limiting toxicity is identified. Up to 15 patients may be enrolled at a dose shown to be tolerated for confirmation of the MTD and/or RP2D.

Interventions

DRUGPRT3645

PRT3645 capsules will be self-administered once daily, continuously, at the dose-level assigned

Sponsors

Prelude Therapeutics
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

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

Inclusion criteria

* Histologically confirmed advanced, recurrent, or metastatic solid tumor malignancy that have either progress or ineligible for standard of care therapy: 1. HR+ and HER2- or HR+ and HER2+ breast cancer 2. Recurrent GBM (IDH wild type) or CDKN2A/B homozygous deleted IDH-mutant astrocytoma 3. KRAS-mutant or SMARCA4 loss NSCLC 4. CDK pathway alternation in any of the following tumor types: malignant mesothelioma, HPV-negative HNSCC (including oral cavity, oropharynx, hypopharynx, and larynx), sarcoma, or NSCLC 5. Estrogen receptor positive with TP53 wild type endometrial cancer * Willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures * Must have measurable or non-measureable (but evaluable) disease * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 or Karnofsky Performance Status (KPS) ≥80% (KPS is for GBM only) * Adequate organ function. * Able to swallow and retain oral medication. * Must provide either archival or fresh tumor tissue sample during screening.

Exclusion criteria

* Participants with advanced, symptomatic, extensive visceral disease. * Active inflammatory bowel disease or chronic diarrhea, short bowel syndrome, any upper gastrointestinal surgery including gastric resection, known malabsorption syndrome, or other condition that may impair absorption of PRT3645. * Treatment with strong inhibitors of CYP3A4. * 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. * Clinically significant or uncontrolled cardiac disease, uncontrolled electrolyte disorders, uncontrolled or symptomatic CNS metastases or leptomeningeal disease except for GBM. * Endometrial cancer patients who had received prior treatment with a CDK 4/6 inhibitor.

Design outcomes

Primary

MeasureTime frameDescription
Dose limiting toxicity (DLT) of PRT3645Baseline through Day 28Dose limiting toxicity will be evaluated over the 28-day observation period
Safety and tolerability of PRT3645: AEs, CTCAE AssessmentsBaseline through approximately 2 yearsSafety and tolerability will be evaluated by incidence of DLTs, laboratory measurements, severity of adverse events (AEs) according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0.
Maximally tolerated dose (MTD)/Recommended phase 2 dose (RP2D) of PRT3645Baseline through approximately 2 yearsThe MTD/RP2D will be established for further investigation in participants with advanced solid tumors

Secondary

MeasureTime frameDescription
Efficacy of PRT3645: Tumor assessment and responsesBaseline through approximately 2 yearsObjective response rate (ORR), Progression-free survival (PFS), Disease control rate (DCR) and Duration of response (DOR) will use RECIST v1.1, mRECIST v1.1, and/or RANO as primary measure for tumor assessment and response.
Pharmacokinetic profile of PRT3645: Minimum and maximum observed plasma concentrationBaseline through approximately 2 yearsPRT3645 pharmacokinetics will be calculated including the minimum and maximum observed plasma concentration.
Pharmacodynamic effect of PRT3645: Target engagementBaseline through approximately 2 yearsPharmacodynamic effect of PRT3645 demonstrating target engagement by assessment of phosphorylation of Rb.

Countries

Singapore, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 9, 2026