Recruiting

Phase 1

Phase 2

FB849A Phase I/II, Open-label Study to Investigate the Safety, Tolerability, PK, and Preliminary Efficacy of FB849

Sponsor:

1ST Biotherapeutics, Inc.

Code:

NCT05761223

Conditions

Advanced Solid Tumor

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Phase Ia dose-escalation part of FB849 Monotherapy

Phase Ib dose-expansion of FB849 monotherapy

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)

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

Study Details

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

Study ID

NCT05761223

Start date

Dec 13, 2023

Status verified date

Aug, 2025

Completion date

Oct, 2026

Anticipated

Primary completion date

Jun, 2026

Anticipated

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

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

Exclusion Criteria:

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.

Study Design

Enrollment

151 participants

Anticipated

Allocation

Non randomized

Intervention Model

Single group

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Phase Ia dose-escalation part of FB849 Monotherapy

Participations will receive FB849 orally once a day.

experimental: Phase Ib dose-expansion of FB849 monotherapy

Participations will receive FB849 orally once a day.

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

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

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

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

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

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

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

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

Interventions

Phase Ia dose-escalation part of FB849 Monotherapy

At a given level dose once daily

Phase Ib dose-expansion of FB849 monotherapy

At recommended dose for expansion cohort once daily

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

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

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

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

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

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

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

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

Primary outcome measure

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 [ Time Frame: DLT Assessment at the end of Cycle 1(each cycle is 21 days.) ]

Central Contacts and Locations

Central contacts

1STBIO Information center

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

Locations

Cleveland Clinic

Recruiting

Cleveland, Ohio, United States, 44195

Mary Crowley Cancer Research Center

Recruiting

Dallas, Texas, United States, 40118

NEXT Oncology San Antonio

Recruiting

San Antonio, Texas, United States, 78229

Next Oncology Virginia

Recruiting

Fairfax, Virginia, United States, 22031

Summit Cancer Centers - Spokane Valley

Recruiting

Spokane, Washington, United States, 99208

More Information

Sponsor

1ST Biotherapeutics, Inc.

Last update posted

Aug 17, 2025

Last verified

Aug, 2025

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by 1ST Biotherapeutics, Inc. on 2025-08-17.