C5951001- A Phase 1 Study of PF-08046876 in Participants with Advanced Solid Tumors.

2025-521729-33-00 Protocol C5951001 Human pharmacology (Phase I) - First administration to humans Ongoing, recruiting

Start 10 Feb 2026 · Status Ongoing, recruiting · 1 EU/EEA countries · 3 sites · Protocol C5951001

Overview

Sponsor-declared trial summary

Phase Human pharmacology (Phase I) - First administration to humans
Status Ongoing, recruiting
Participants planned 310
Countries 1
Sites 3

advanced solid tumors

Key facts

Sponsor
Pfizer Inc.
Participant type
Patients
Age range
18-64 years, 65+ years
Gender
Male and Female
Therapeutic area
Diseases [C] - Neoplasms [C04]
Trial duration
10 Feb 2026 → ongoing
Decision date (initial)
2025-12-23
Transition trial
No
Low-intervention
No
Rare-disease indication
No
Vulnerable population
No

Trial design

CTIS Part I — objectives, methods, condition coding

Conditions and MedDRA coding

advanced solid tumors

VersionLevelCodeTermSystem organ class
21.1 LLT 10065147 Malignant solid tumor 10029104

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Pfizer Inc.

Sponsor organisation
Pfizer Inc.
Address
66 Hudson Boulevard East
City
New York
Postcode
10001-2189
Country
United States

Scientific contact point

Organisation
Pfizer Inc.
Contact name
Clinical Medical Lead

Public contact point

Organisation
Pfizer Inc.
Contact name
Clinical Medical Lead

Locations

1 EU/EEA country · 3 investigational sites

By country

CountryMS statusPlanned subjectsSites
Spain Ongoing, recruiting 70 3
Rest of world
United Kingdom, United States, Canada
240

Investigational sites

Spain

3 sites · Ongoing, recruiting
Hospital Universitario Fundacion Jimenez Diaz
Medical Oncology, Avenida De Los Reyes Catolicos 2, 28040, Madrid
Hospital Universitario 12 De Octubre
Medical Oncology, Avenida De Cordoba Sn, 28041, Madrid
Hospital Universitari Vall D Hebron
Departamento de Oncologia- VHIO, Passeig De La Vall D'Hebron 119-129, 08035, Barcelona

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Country Trial startTrial end Recruitment startRecruitment end Early termination
Spain 2026-02-10 2026-02-19

Application history

1 submissions — initial application plus substantial / non-substantial modifications

#TypeCodeSubmittedReference MSConclusionDecision date
1 INITIAL IN 2025-09-03 Spain Acceptable
2025-12-18
2025-12-23