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GB002

Phase 2

Pulmonary Arterial Hypertension | Small molecule | Cardiovascular |Gossamer Bio, Inc.|Last Updated: Jul 27, 2026

Target and mechanism

Molecular targetPDGFR, CSF1R, c-KIT
Target classReceptor Tyrosine Kinases
ModalitySmall molecule

Also known as GB002 (seralutinib)

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials2
Total Enrollment82

FDA Designations

No designations recorded

Clinical trial landscape

GB002 · 4 trials · 3 indications

Phase 2 2Phase 1 2
NCT04816604Open-label Extension Study of GB002 in Adult Subjects With Pulmonary Arterial Hypertension (PAH)Pulmonary Arterial Hypertension
ACTIVE NOT_RECRUITING74 Analytics
NCT04456998GB002 in Adult Subjects With Pulmonary Arterial Hypertension (PAH)Pulmonary Artery Hypertension
COMPLETED86 Analytics
PHASE2ACTIVE NOT_RECRUITING
Open-label Extension Study of GB002 in Adult Subjects With Pulmonary Arterial Hypertension (PAH)
Pulmonary Arterial Hypertension
NCT0481660474
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PHASE2COMPLETED
GB002 in Adult Subjects With Pulmonary Arterial Hypertension (PAH)
Pulmonary Artery Hypertension
NCT0445699886
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Study Endpoints

Primary Endpoints

Number of Participants With Treatment Emergent Adverse Events
From first dose of study drug up to 80 months or availability of commercial product
Change From Baseline to Week 24 in Pulmonary Vascular Resistance (PVR)
Baseline, Week 24

PVR was evaluated using right heart catheterization (RHC).

Number of participants with Treatment-Related Adverse Events GB002 (Main study)
Up to 45 days

To evaluate the safety and tolerability of GB002

Number of participants with Treatment-Related Adverse Events GB002 (OLE study)
Up to 200 days

To evaluate the long-term safety and tolerability and efficacy of GB002

Number of Participants With Treatment-Emergent Adverse Events (TEAEs)
SAD: from first dose of study drug to 11 days, MAD: from first dose of study drug to 35 days

An adverse event (AE) is defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. A serious AE (SAE) is one that, in the view of either the investigator or Sponsor, results in any of the following outcomes: death, a life-threatening AE, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. A TEAE is defined as any AE that has an onset on or after the first dose of study drug and before the end of study/end of treatment (EoS/ET) visit, or any pre-existing condition that has worsened in severity on or after the first dose of study drug and before the EoS/ET visit.

Number of Participants With Vital Sign Findings Reported as TEAEs
SAD: from first dose of study drug to 11 days, MAD: from first dose of study drug to 35 days

Vital signs evaluated included blood pressure, pulse oximetry, respiratory rate, and temperature.

Number of Participants With Clinically Significant Findings in Physical Examinations
SAD: from first dose of study drug to 11 days, MAD: from first dose of study drug to 35 days

Physical examination assessments included: physical exam for general appearance; head, ears, eyes, nose and throat; thyroid; lymph nodes; back and neck; heart; chest; lungs; abdomen; skin; and extremities, musculoskeletal and neurological.

Number of Participants With Clinically Significant Changes From Baseline in ECG Data (Overall Interpretation)
SAD: Baseline, Day 2, 24 hours; MAD: Baseline, Day 8, 24 hours

12-lead electrocardiograms (ECG) assessments included heart rate, PR interval, QRS duration, QT interval, QTc interval, QTc interval corrected using Bazett's formula (QTcB), QTc interval corrected using Fridericia's formula (QTcF), RR interval.

Number of Participants With Clinically Significant Abnormal Findings in Pulmonary Function Tests
SAD: from first dose of study drug to 11 days, MAD: from first dose of study drug to 35 days

Pulmonary function tests included forced vital capacity; forced expiratory volume in 1 second (FEV1); forced expiratory flow 25%-75% (FEF25-75); percent predicted forced vital capacity; percent predicted FEV1; and percent predicted FEF25-75.

Pharmacokinetic (PK) Analysis of Inhaled GB002: Maximum Concentration (Cmax), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Time to Cmax (Tmax), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Area Under the Curve From Time 0 Hours to Last Quantifiable Concentration (AUClast), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Area Under the Curve From Time 0 Hours to Infinity (AUCinf), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Apparent Terminal Elimination Half-Life (t1/2), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Apparent Total Plasma Clearance (CL/F), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration

CL/F is based on nominal (scheduled) dose.

PK Analysis of Inhaled GB002: Apparent Volume of Distribution (Vz/F), SAD
0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration

Vz/F is based on nominal (scheduled) dose.

PK Analysis of Inhaled GB002: Cmax After Dose 1, MAD
Days 1 and 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Tmax After Dose 1, MAD
Days 1 and 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Area Under the Curve From Time Zero to 24 Hours Postdose (AUC0-24), MAD
Days 1 and 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Trough Plasma Concentration (Ctrough), MAD
Days 1 and 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Accumulation Ratio (Rac) for Cmax After Dose 1, MAD
Days 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Rac for AUC0-24, MAD
Days 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Rac for Ctrough, MAD
Days 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: t1/2, MAD
Day 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Apparent Total Plasma Clearance at Steady-State (CLss/F), MAD
Day 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration
PK Analysis of Inhaled GB002: Vz/F, MAD
Day 7: 0 hour (predose), and then at 3, 10, 20, 30, 40 minutes, and 1, 2, 4, 8, 12, 24, 36, and 48 hours after the start of study treatment administration

Secondary Endpoints

Change from Baseline Over Time on the Six-Minute Walk Test (6MWT)
Baseline, up to 80 months or availability of commercial product
Change From Baseline to Week 24 in Distance Achieved on the Six-Minute Walk Test (6MWT)
Baseline, Week 24
Pharmacokinetics: Time to Reach Maximum Concentration (Tmax) of GB002 (Main study)
14 days
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Study Design & Arms

AllocationNA
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
GB002 (seralutinib)EXPERIMENTALGB002 (seralutinib) inhaled orally twice per day (BID)
PlaceboPLACEBO_COMPARATORPlacebo inhaled orally BID for 24 weeks
Cohort 1EXPERIMENTALPatients will be randomized to receive inhaled GB002 or Placebo daily for 14 days
Cohort 2EXPERIMENTALPatients will be randomized to receive inhaled GB002 or Placebo daily for 14 days
Open Label ExtensionEXPERIMENTALEligible subjects may participate in the Open Label Extension (OLE) study for a period of 24 weeks.
Cohort 1AEXPERIMENTALDose 1 Single Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 2AEXPERIMENTALDose 2 Single Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 3AEXPERIMENTALDose 3 Single Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 4AEXPERIMENTALDose 4 Single Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 5AEXPERIMENTALDose 5 Single Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 1BEXPERIMENTALDose 1 Multiple Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 2BEXPERIMENTALDose 2 Multiple Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.
Cohort 3BEXPERIMENTALDose 3 Multiple Ascending Dose Protocol: within the cohort, 6 participants receive active drug (GB002) and 2 participants receive placebo.

Interventions

NameTypeDescription
GB002 (seralutinib)DRUGCapsule containing GB002 (seralutinib)
Generic Dry Powder InhalerDEVICEGeneric dry powder inhaler for GB002 (seralutinib) delivery
PlaceboDRUGMatching capsule containing placebo
GB002DRUGGB002 low dose or high dose for inhalation
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Eligibility Criteria

Age Range18 Years to 80 Years
SexALL
Healthy VolunteersNo
Study Sites28

Inclusion Criteria: Type of Subject and Disease Characteristics 1. Subjects must have completed a prior GB002 PAH study and, in the opinion of the Investigator and Sponsor, have been compliant with study procedures and have completed treatment with IP through parent study end-of-treatment (EOT) vi...

Countries:United StatesAustraliaCzechiaFranceGermanySpainUnited KingdomAustriaBelgiumCanadaSerbia
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Competitive Landscape -Pulmonary Arterial Hypertension 39 trials

CompanyTickerTrialsLead PhaseDrugs
United Therapeutics CorporationUTHR5PHASE3Ralinepag
Merck & Co., Inc.MRK6PHASE3Riociguat
Insmed IncorporatedINSM4PHASE3Treprostinil Palmitil
Johnson & JohnsonJNJ4PHASE3Selexipag
Liquidia CorporationLQDA4PHASE3L606
Tenax Therapeutics, Inc.TENX3PHASE3TNX-103
Inhibikase Therapeutics, Inc.IKT1PHASE3IKT-001
Gossamer Bio, Inc.GOSS2PHASE3Seralutinib
Regeneron Pharmaceuticals, Inc.REGN1PHASE2REGN13335
Pfizer Inc.PFE1PHASE2PF-07868489
Tectonic Therapeutic IncTECX1PHASE2TX000045- Dose A, TX000045- Dose B
Abbott LaboratoriesABT1N/AUndisclosed
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Recent Changes (Last 90 Days)

LOWJul 27, 2026NCT04816604lastUpdatePostDate: changed
LOWJul 27, 2026NCT04816604lastUpdatePostDate: changed
LOWJul 27, 2026NCT04816604lastUpdatePostDate: changed

Frequently asked questions about GB002

What is GB002 used for?

GB002, also known as seralutinib, is an investigational small molecule being developed for the treatment of pulmonary arterial hypertension (PAH), a type of high blood pressure affecting the arteries in the lungs. It is also being studied in trials involving safety issues and pulmonary artery hypertension. GB002 is not yet approved and remains in clinical development.

What does GB002 target?

GB002 targets receptor tyrosine kinases, specifically PDGFR, CSF1R, and c-KIT. By inhibiting these targets, the drug is designed to address pathways involved in pulmonary arterial hypertension. This mechanism is being evaluated in clinical trials for its potential to treat the condition.

Who makes GB002?

GB002 is being developed by Gossamer Bio, Inc., a biopharmaceutical company traded on the stock exchange under the ticker symbol GOSS. The company is conducting clinical trials to evaluate the safety and efficacy of GB002 in patients with pulmonary arterial hypertension.

What phase is GB002 in?

GB002 is currently in Phase 2 clinical development. It has completed Phase 1 trials and is being studied in Phase 2 trials for pulmonary arterial hypertension. The drug is investigational and has not received FDA approval, as it is still undergoing clinical evaluation.

What clinical trials is GB002 in?

GB002 has been studied in several clinical trials, including NCT03473236, a Phase 1 safety trial in healthy volunteers; NCT03926793, a Phase 1 study in PAH patients; NCT04456998, a Phase 2 trial in adults with PAH; and NCT04816604, an open-label extension study. These trials have enrolled a total of 86 participants.

Is GB002 the same as seralutinib?

Yes, GB002 is also known as seralutinib. The drug is referred to by both names in clinical research and development contexts. Gossamer Bio is developing this compound for pulmonary arterial hypertension, and it is currently in Phase 2 trials.

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