PF-07260437 for Solid Tumors

(C4431001 Trial)

Recruiting at 18 trial locations

Overseen By Pfizer CT.gov Call Center

Age: 18+

Sex: Any

Trial Phase: Phase 1

Sponsor: Pfizer

Must not be taking: Immunosuppressive therapy

Disqualifiers: Active malignancy, Symptomatic visceral spread, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 5

30 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new treatment, PF-07260437, a specialized antibody targeting specific proteins in cancer cells. The study aims to assess the safety and effectiveness of this treatment for individuals with advanced or metastatic breast, ovarian, or endometrial cancer. The trial consists of three parts, each concentrating on different types of breast cancer: hormone receptor-positive, HER2-negative, and triple-negative. Participants with these specific cancer types who have seen limited success with previous treatments might be suitable for this trial. As a Phase 1 trial, this research seeks to understand how the treatment functions in people, offering participants the chance to be among the first to receive this new therapy.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

Is there any evidence suggesting that PF-07260437 is likely to be safe for humans?

Research shows that PF-07260437 is under study as a treatment for certain solid tumors. It targets specific proteins on cancer cells. Although detailed safety information remains limited, this is a Phase 1 trial. Phase 1 trials typically mark the first time a treatment is tested in humans, focusing on safety and potential side effects.

Phase 1 trials indicate that the treatment is in the early testing stages, so information on tolerance and side effects may be limited. However, reaching this stage suggests sufficient early evidence to interest researchers in its potential.

Prospective participants should discuss with the study team the known side effects and what to expect. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Unlike the standard treatments for solid tumors, which often include surgery, chemotherapy, and radiation therapy, PF-07260437 offers a new approach by potentially targeting specific tumor characteristics at a molecular level. Researchers are excited about PF-07260437 because it may have a novel mechanism of action that differentiates it from existing therapies. This could lead to more precise targeting of tumor cells, potentially resulting in fewer side effects and improved outcomes for patients.

What evidence suggests that PF-07260437 might be an effective treatment for solid tumors?

Research has shown that PF-07260437 is a promising treatment for certain solid tumors with the B7-H4 protein, found in cancers such as breast, ovarian, and endometrial cancer. This treatment is a bispecific antibody, targeting both cancer cells and T-cells, a type of immune cell, to help the body fight cancer. Early studies demonstrated that PF-07260437 can shrink tumors or slow their growth. Participants in this trial will receive PF-07260437 in different treatment arms, including monotherapy dose escalation and tumor-specific dose expansion. Although still under testing, these initial findings suggest it could effectively treat certain advanced cancers. ^{1 2 4 5 6}

Who Is on the Research Team?

Pfizer CT.gov Call Center

Principal Investigator

Pfizer

Are You a Good Fit for This Trial?

Inclusion Criteria

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 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

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

Exclusion Criteria

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.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Dose Escalation

Participants receive PF-07260437 to evaluate safety, tolerability, and pharmacokinetics

4-6 weeks

Weekly visits for dose escalation monitoring

Dose Expansion

Participants receive PF-07260437 in tumor-specific arms to further evaluate antitumor activity

Up to 35.1 weeks

Visits every 3 weeks for treatment and monitoring

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

2 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• PF-07260437

How Is the Trial Designed?

Group I: Monotherapy dose escalation (Part 1) Experimental Treatment 1 Intervention

Participants will receive PF-07260437

Group II: Dose Expansion (Part 2C) - Tumor specific Arm C Experimental Treatment 2 Interventions

Participants will receive PF07260437

Group III: Dose Expansion (Part 2B) - Tumor specific Arm B Experimental Treatment 2 Interventions

Participants will receive PF-07260437

Group IV: Dose Expansion (Part 2A) - Tumor specific Arm A Experimental Treatment 2 Interventions

Participants will receive PF-07260437

Who Is Running the Clinical Trial?

Pfizer

Lead Sponsor

Trials

4,712

Recruited

50,980,000+

Known For

Vaccine Innovations

Top Products

Viagra, Zoloft, Lipitor, Prevnar 13

Albert Bourla

Pfizer

Chief Executive Officer since 2019

PhD in Biotechnology of Reproduction, Aristotle University of Thessaloniki

Patrizia Cavazzoni

Pfizer

Chief Medical Officer

MD from McGill University

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT05067972

A Study of PF-07260437 in Advanced or Metastatic Solid ... A study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of PF-07260437, a B7-H4 x CD3 bispecific ...

2. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40366350/

A Novel B7-H4xCD3 Bispecific T-cell Engager (PF- ... These data support the clinical testing of PF-07260437 for treating B7-H4-expressing solid tumors, including breast cancer. ©2025 The ...

3. pfizer.com pfizer.com/sites/default/files/plsr-studies/C4431001%20Plain%20Language%20Study%20Results%20Summary%20%28PLSRS%29%20Phase%201%20PK%20Primary%20Endpoint.pdf

– Thank You – PF-07260437 is an injectable study medication that researchers think may help with advanced or metastatic solid tumors. PF-07260437 is designed.

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11985252/

B7 Homolog 4 (B7-H4)-Directed Agents in Oncology ... B7-H4–targeted agents represent a promising class of drugs that have demonstrated early antitumor activity in solid tumors, particularly breast, endometrial, ...

5. aacrjournals.org aacrjournals.org/mct/article/24/7/976/763168/A-Novel-B7-H4xCD3-Bispecific-T-cell-Engager-PF

A Novel B7-H4xCD3 Bispecific T-cell Engager (PF-07260437 ... These data support the clinical testing of PF-07260437 for treating B7-H4–expressing solid tumors, including breast cancer. Graphical Abstract. graphic. View ...

6. meridian.allenpress.com meridian.allenpress.com/innovationsjournals-JIPO/article/8/2/153/506454/B7-Homolog-4-B7-H4-Directed-Agents-in-Oncology

B7 Homolog 4 (B7-H4)-Directed Agents in Oncology ... Also terminated without data was PF-07260437 ... 25. A safety and tolerability study of NC762 in subjects with advanced or metastatic solid tumors.