A Phase I/II, Open-label Study to Investigate the Safety, Tolerability, PK, and Preliminary Efficacy of FB849

NCT05761223 | Recruiting Phase 1 FDA Drug

• 3 other identifiers: FB849_P101KEYNOTE-F25MK-3475-F25
• Study Type: interventional
• Target: 151
• Locations: 1 country
• Sites: 5

Brief Summary

This is the first-in-human, multicenter, open-label Phase I/II study to investigate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of FB849 alone and in combination with pembrolizumab in subjects with advanced solid tumors for whom no standard therapy is available.

Conditions

Advanced Solid Tumor

Outcome Measures

Primary Outcomes (1)

• To assess the safety and tolerability of FB849 and to identify maximum tolerated dose (MTD)/ recommended Phase II dose (RP2D) and dosing schedule of FB849 in subjects with advanced solid tumors

  The MTD is defined to be the highest safe dose with an estimated DLT rate less than 30.

  DLT Assessment at the end of Cycle 1(each cycle is 21 days.)

Secondary Outcomes (2)

• To determine the pharmacokinetic parameters such as Peak Plasma Concentration (Cmax) of FB849

  Blood: Predose, 1, 2, 4, 8, 12, 24 hours postdose at C1D1 and C1D21; predose and 4, 8, and 24 hours postdose at C1D8; predose at C1D15; and predose on C2D1, C4D1, and C6D1, Urine: predose and 0-4 hour, 4-8 hour, 8-12 hour, 12-24 hour post-dose

• To assess preliminary anti-tumor activity of FB849

  every 6 weeks (± 3 days) in the first 18 weeks, then every 12 weeks (± 7 days) thereafter until disease progression assessed up to approximately 3 years

Study Arms (6)

Phase Ia dose-escalation part of FB849 Monotherapy

EXPERIMENTAL

Participations will receive FB849 orally once a day.

Drug: Phase Ia dose-escalation part of FB849 Monotherapy

Phase Ib dose-expansion of FB849 monotherapy

EXPERIMENTAL

Participations will receive FB849 orally once a day.

Drug: Phase Ib dose-expansion of FB849 monotherapy

Phase IIa dose-escalation part of FB849 in Combination with Pembrolizumab

EXPERIMENTAL

Participations will receive FB849 orally once a day in combination with pembrolizumab.

Drug: Phase IIb dose-escalation part of FB849 in Combination with Pembrolizumab

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type A cancer)

EXPERIMENTAL

Participations will receive FB849 orally once a day in combination with pembrolizumab.

Drug: Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type A cancer)

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type B cancer)

EXPERIMENTAL

Participations will receive FB849 orally once a day in combination with pembrolizumab.

Drug: Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type B cancer)

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type C cancer)

EXPERIMENTAL

Participations will receive FB849 orally once a day in combination with pembrolizumab.

Drug: Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type C cancer)

Interventions

Phase Ia dose-escalation part of FB849 Monotherapy DRUG

At a given level dose once daily

Also known as: FB849

Phase Ia dose-escalation part of FB849 Monotherapy

Phase Ib dose-expansion of FB849 monotherapy DRUG

At recommended dose for expansion cohort once daily

Also known as: FB849

Phase Ib dose-expansion of FB849 monotherapy

Phase IIb dose-escalation part of FB849 in Combination with Pembrolizumab DRUG

At recommended dose for expansion cohort once daily in combination with pembrolizumab

Also known as: FB849, KEYTRUDA®

Phase IIa dose-escalation part of FB849 in Combination with Pembrolizumab

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type A cancer) DRUG

At recommended dose for expansion cohort once daily in combination with pembrolizumab

Also known as: FB849, KEYTRUDA®

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type A cancer)

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type B cancer) DRUG

At recommended dose for expansion cohort once daily in combination with pembrolizumab

Also known as: FB849, KEYTRUDA®

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type B cancer)

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type C cancer) DRUG

At recommended dose for expansion cohort once daily in combination with pembrolizumab

Also known as: FB849, KEYTRUDA®

Phase IIb dose-expansion part of FB849 in Combination with Pembrolizumab (Type C cancer)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Subject should understand, sign, and date the written ICF prior to screening.
• Male or female aged 18 years or older.
• Subjects must have at least 1 measurable target lesion according to RECIST version 1.1.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
• Life expectancy ≥ 3 months in the opinion of the investigator.
• Adequate organ function and bone marrow function as indicated by the following screening assessments performed within 14 days prior to the first dose of study treatment

You may not qualify if:

• Known allergy or hypersensitivity to any component of the study treatment.
• Has a known additional malignancy that is progressing or has required active treatment.
• Has abnormal or inadequately controlled endocrine function.
• Inability to take oral medication or significant nausea and vomiting, malabsorption, external biliary shunt, or significant bowel resection that would preclude adequate absorption of oral medication.
• Previous anti-cancer therapy, including chemotherapy (chemotherapy with nitrosourea or mitomycin should be at least 6 weeks prior to initiation of study treatment), radiotherapy, molecular targeted therapy, or other investigational drugs received ≤ 4 weeks; endocrine therapy ≤ 2 weeks or ≤ 5-half-lives (whichever is shorter) prior to initiation of study treatment.

Sponsors & Collaborators

• 1ST Biotherapeutics, Inc.: lead
• Merck Sharp & Dohme LLC: collaborator

Study Sites (5)

Cleveland Clinic

Cleveland, Ohio, 44195, United States

RECRUITING

Mary Crowley Cancer Research Center

Dallas, Texas, 40118, United States

RECRUITING

NEXT Oncology San Antonio

San Antonio, Texas, 78229, United States

RECRUITING

Next Oncology Virginia

Fairfax, Virginia, 22031, United States

RECRUITING

Summit Cancer Centers - Spokane Valley

Spokane, Washington, 99208, United States

RECRUITING

MeSH Terms

Interventions

pembrolizumab

Study Officials

• 1STBIO Chief Development Officer

  1ST Biotherapeutics

  STUDY DIRECTOR

Central Study Contacts

1STBIO Information center

CONTACT

+82-31-895-4677; info@1stbio.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: The study will be conducted in 3 parts: Phase I dose-escalation part with FB849 monotherapy and Phase II dose-escalation and dose-expansion parts of FB849 in combination with pembrolizumab

Study Record Dates

• First Submitted: February 20, 2023
• First Posted: March 9, 2023
• Study Start: December 13, 2023
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): October 1, 2026
• Last Updated: August 17, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (5)