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Ovarian NeoplasmsPhase 1C4431001NCT05067972

A Study of PF-07260437 in Advanced or Metastatic Solid Tumors

A Phase 1 study testing PF-07260437 and B7-H4 IHC in people with Ovarian Neoplasms and Endometrial Neoplasms, run by Pfizer at 15 sites in 2 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

A study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of PF-07260437, a B7-H4 x CD3 bispecific mAb, in participants aged ≥18 years of age with advanced or metastatic breast cancer, ovarian cancer or endometrial cancer. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
PF-07260437 and B7-H4 IHC
Could I receive a placebo?
No, everyone receives an active treatment
How many people
30 participants
Where
15 sitesin 2 countries
Study dates
7 Oct 2021to 17 Oct 2023
Phase
Phase 1
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Part 1: Histological/cytological diagnosis of selected locally advanced or metastatic breast cancer, endometrial cancer and ovarian cancer
  • Part 2A:In second line or more, participants with histological/cytological diagnosis of locally advanced or metastatic HR+ HER2- breast cancer showing high B7-H4 expression
  • Part 2B: In second line or more participants with histological or cytological diagnosis of locally advance or metastatic HR+ Her2- breast cancer or triple negative breast cancer (TNBC) with no biomarker pre-selection
  • Part 2C: In second line or more participants with histological diagnosis of locally advance or metastatic triple negative breast cancer with high B7-H4 expression
  • Thyroid function within normal laboratory range; in participants with abnormal thyroid function if Free T4 is normal and participant is clinically euthyroid, participants is eligible

Who cannot join

  • Participants with any active malignancy within 3 years prior to enrollment
  • Participants with advanced/metastatic, symptomatic, visceral spread, that are at risk of life-threatening complications in the short term (including participants with massive uncontrolled effusions [pleural, pericardial, peritoneal], pulmonary lymphangitis, and over 50% liver involvement).
  • History of Grade ≥3 immune mediated adverse events (including liver function tests that where considered drug related and cytokine release syndrome) that was considered related to prior immune modulatory therapy (eg, immune checkpoint inhibitors, co stimulatory agents, etc.) and required immunosuppressive therapy within 1 year of treatment.

Trial locations and contacts

15 sites in 2 countries.

15 sites in 2 countries

United States12 sites

  • University of Chicago Medical Center

    Chicago, Illinois, 60637

  • City of Hope (City of Hope National Medical Center, City of Hope Medical Center)

    Duarte, California, 91010

  • Swedish Cancer Institute Edmonds Campus

    Edmonds, Washington, 98026

  • University of Chicago Comprehensive Cancer Center at Silver Cross Hospital

    New Lenox, Illinois, 60451

  • The University of Chicago Medicine Center of Advanced Care Orland Park

    Orland Park, Illinois, 60462

  • NEXT Oncology

    San Antonio, Texas, 78229

  • Swedish Cancer Institute

    Seattle, Washington, 98104

  • Fred Hutchinson Cancer Center

    Seattle, Washington, 98109

  • University of Washington Medical Center - Mountlake

    Seattle, Washington, 98195

  • Moffitt Cancer Center at McKinley Campus

    Tampa, Florida, 33612

  • Moffitt Cancer Center

    Tampa, Florida, 33612

  • Montefiore Einstein Center for Cancer Care

    The Bronx, New York, 10461

Other trials in United States

Puerto Rico3 sites

  • Pan American Center for Oncology Trials, LLC

    Rio Piedras, 00935

  • Pan American Center for Oncology Trials- Hospital Oncologico

    Rio Piedras, 00935

  • Pan American Center for Oncology Trials

    Rio Piedras, 00935

Other trials in Puerto Rico

About this study

Official title: A PHASE 1 DOSE ESCALATION AND EXPANSION STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETIC, PHARMACODYNAMIC, AND ANTITUMOR ACTIVITY OF PF-07260437 IN ADVANCED OR METASTATIC SOLID TUMORS

A study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of PF-07260437, a B7-H4 x CD3 bispecific mAb, in participants aged ≥18 years of age with advanced or metastatic breast cancer, ovarian cancer or endometrial cancer. Adult participants with other advanced or metastatic high B7-H4 expressing tumors may be considered after discussion with and approval from sponsor.

Being tested
PF-07260437, B7-H4 IHC
Keywords
Cancer of Endometrium, Cancer of the Endometrium, Carcinoma of Endometrium, Endometrial Cancer, Endometrial Carcinoma, Endometrium Cancer, Neoplasms, Endometrial, Cancer of Ovary, Cancer of the Ovary, Neoplasms, Ovarian, Ovarian Cancer, Ovary Cancer, Ovary Neoplasms, Breast Cancer, Breast Carcinoma, Breast Tumors, Cancer of Breast, Cancer of the Breast, Human Mammary Carcinoma, Malignant Neoplasm of Breast
Medical subject headings
Ovarian Neoplasms, Endometrial Neoplasms, Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PF-07260437Drug

    Also called B7-H4

    B7-H4 x CD3 bi-specific mAb

  • B7-H4 IHCDiagnostic test

    B7-H4 expression

Study groups in NCT05067972
Study groupRoleWhat they receive
Monotherapy dose escalation (Part 1)ExperimentalParticipants will receive PF-07260437
Receives: Drug: PF-07260437
Dose Expansion (Part 2A) - Tumor specific Arm AExperimentalParticipants will receive PF-07260437
Receives: Drug: PF-07260437; Diagnostic Test: B7-H4 IHC
Dose Expansion (Part 2B) - Tumor specific Arm BExperimentalParticipants will receive PF-07260437
Receives: Drug: PF-07260437; Diagnostic Test: B7-H4 IHC
Dose Expansion (Part 2C) - Tumor specific Arm CExperimentalParticipants will receive PF07260437
Receives: Drug: PF-07260437; Diagnostic Test: B7-H4 IHC

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of Participants With Dose-Limiting Toxicities (DLTs) in Dose Escalation - Part 1

    Any of the following treatment-related adverse events (AEs) occurring during the DLT observation period were classified as DLTs: Hematological DLTs: neutropenia Grade (G) 4, febrile neutropenia, ≥G3 for >7d (days), G3 with infection; thrombocytopenia G4, G3 with bleeding or requiring platelet transfusion; anemia G4, G3 requiring blood transfusion. Non-hematologic: hepatic toxicity; ≥G3 fatigue for ≥5d, ≥G3 nausea/vomiting or diarrhea for ≥3d, ≥G3 cytokine release syndrome (CRS) of any duration/QTcF prolongation/anaphylaxis, G5 AE without clear reason; immune-related (ir)AE: ≥G4 irAEs/colitis, G3/4 non-infectious pneumonitis, G2 pneumonitis not resolved to ≤G1 within 3d of the initiation of max supportive care. Severity of AEs were graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, with the exception of CRS, which were graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) CRS Consensus Grading for CRS.

    Measured: The first dose of the study intervention (C1D1) through Day 28 for participants without a priming dose or through Day 42 for participants with a priming dose.

  2. Number of Participants With Treatment Emergent Adverse Events (TEAEs) - Part 1

    An AE was any untoward medical occurrence in a participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. TEAE was defined as any AE that occurred from first dose of study intervention to either last dose of study treatment + 90 days, start of new anti-cancer therapy, or completion in study as determined by disposition, whichever was earliest. A serious AE (SAE) was defined as any untoward medical occurrence that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, persistent disability/incapacity, or was a congenital anomaly/birth defect. AEs were graded by the investigator according to CTCAE v5.0.

    Measured: Baseline (Day 1 of dosing ) through 4 week follow-up, up to 35.1 weeks

  3. Number of Participants With Clinically Significant Laboratory Abnormalities - Part 1

    Laboratory parameters included: hematology (hemoglobin, hematocrit, red blood cell, platelet and white blood cell count, neutrophils, eosinophils, monocytes, basophils and lymphocytes), chemistry (blood urea nitrogen, creatinine, sodium, potassium, aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase, albumin, total protein and serum pregnancy test [for all female participants]) and urine (urine pregnancy test [for all female participants]). Clinical significance of laboratory parameters was determined at the investigator's discretion.

    Measured: Baseline through up to 35.1 weeks

Secondary outcomes (5)

  1. Number of Participants With Immune-Related Adverse Events (irAEs)

    irAEs included gastrointestinal (ie, diarrhea/colitis), dermatological (ie, rash), pulmonary (ie, pneumonitis), hepatic (ie, liver test elevation), renal (ie, creatinine increased), cardiac (ie, myocarditis), endocrine (ie, endocrine disorder), and other toxicities.

    Measured: Day 1 up to 90 days after the last dose of study intervention (Day 246 [C9D15]), up to approximately 336 days

  2. Number of Participants by Categories of Anti-Drug Antibody (ADA) Against PF-07260437

    Number of participants with positive ADA against PF-07257876 were summarized for each treatment arm. A participant had treatment-induced ADA response if he/she had negative or missing ADA at baseline and ≥1 post-treatment ADA positive titer. A participant had treatment-boosted ADA response if he/she had positive titer at baseline and a ratio of ≥4 in titer (dilution) to baseline in ≥1 post-treatment sample.

    Measured: On Day 1 of Cycle 1, 2, 3. From Cycle 4 onwards: collection on Day 1 of every 3 cycles (C4D1, C7D1, etc.) until end-of-treatment visit, up to 35.1 weeks.

  3. Single Dose: Maximal Concentration (Cmax)

    Maximum observed serum concentration following single dose of PF-07260437. The multiple dose PK samples were not collected due to dose interruption or discontinuation. The PK sampling schedule was designed to evaluate the dosing interval of 2 weeks. Since the 100/300/800 group received the second dose (300 ug) only 1 week after the first dose. The PK parameters were not calculable.

    Measured: Day 1 pre-dose, 1, 4, 8, 24, 48 and 168 hours post-dose, till Day 15 pre-dose in Cycle 1

  4. Single Dose: Area Under the Curve (AUCtau)

    Area under the plasma concentration-time profile from time 0 to time tau (τ), the dosing interval following single dose of PF-07260437. The multiple dose PK samples were not collected due to dose interruption or discontinuation. The PK sampling schedule was designed to evaluate the dosing interval of 2 weeks. Since the 100/300/800 group received the second dose (300 ug) only 1 week after the first dose. The PK parameters were not calculable.

    Measured: Day 1 pre-dose, 1, 4, 8, 24, 48 and 168 hours post-dose, till Day 15 pre-dose in Cycle 1

  5. Single Dose: Time to Maximal Plasma Concentration (Tmax)

    Time to maximal plasma concentration following single dose of PF-07260437. The multiple dose PK samples were not collected due to dose interruption or discontinuation. The PK sampling schedule was designed to evaluate the dosing interval of 2 weeks. Since the 100/300/800 group received the second dose (300 ug) only 1 week after the first dose. The PK parameters were not calculable.

    Measured: Day 1 pre-dose, 1, 4, 8, 24, 48 and 168 hours post-dose, till Day 15 pre-dose in Cycle 1

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted5 Oct 2021
  2. Study start7 Oct 2021
  3. Primary completion17 Oct 2023
  4. Study completion17 Oct 2023

Why it stopped: Pfizer has made an internal business decision to not continue further development of PF-07260437. This decision was not due to major safety concerns or requests from any regulatory authorities.

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
30 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05067972
Sponsor's protocol ID
C4431001
Acronym
C4431001
Status last verified
Apr 2025
First submitted
24 Sep 2021
Last updated
6 May 2025
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.

Publications

  • Yan F, Cruz-Correa M, Specht J, Wang EW, Lu J, Soliman H, Jackson-Fisher A, Tang SY, Jiang S, Le Corre C, Li M, Sommerhalder D. A phase 1 study of PF-07260437, a B7-H4 x CD3 bispecific T-cell engager, in patients with advanced or metastatic breast, ovarian, and endometrial cancer. Invest New Drugs. 2026 Aug;44(4):305-316. doi: 10.1007/s10637-026-01614-2. Epub 2026 May 22.

    PubMed 42171881

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing PF-07260437 and B7-H4 IHC in people with Ovarian Neoplasms and Endometrial Neoplasms, run by Pfizer at 15 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 6 May 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 15 sites in United States, Puerto Rico. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 6 May 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Participants With Dose-Limiting Toxicities (DLTs) in Dose Escalation - Part 1 (time frame: The first dose of the study intervention (C1D1) through Day 28 for participants without a priming dose or through Day 42 for participants with a priming dose.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05067972, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2025.

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