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PF-07104091

Phase 2

Small Cell Lung Cancer | Small molecule | Oncology |Pfizer, Inc.|Trials Updated: May 6, 2026

PF-07104091 development status

Highest phase Phase 2
Registered trials 1 across 1 sponsor since Aug 2025

PF-07104091 target and mechanism

ModalitySmall molecule

Also known as PF-07104091 monotherapy dose escalation

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDBiomarker
Total Trials1
Total Enrollment157

FDA Designations

No designations recorded

PF-07104091 clinical trials

PF-07104091 · 1 trial · 3 indications

Phase 2 1
NCT04553133PF-07104091 as a Single Agent and in Combination TherapySmall Cell Lung Cancer
ACTIVE NOT_RECRUITING157 Analytics
PHASE2ACTIVE NOT_RECRUITING
PF-07104091 as a Single Agent and in Combination Therapy
Small Cell Lung CancerUnlock trial analytics

Study Endpoints

Primary Endpoints

Dose Escalation: Number of participants with Dose-limiting toxicities (DLT) during first cycle
28 days

Number of participants with DLTs, which are typically Grade 3 or higher adverse events will be summarized by dose level

To evaluate incidence of treatment emergent adverse events and laboratory abnormalities
From baseline until end of study treatment or study completion (approximately 2 years)

Type, incidence, severity, timing, seriousness and relationship to study treatment of adverse events and any laboratory abnormalities will be summarized by dose level

Evaluate pulse rate that is out of normal range and changes in pulse rate as compared to baseline
From baseline until end of study treatment or study completion (approximately 2 years)

Identify pulse rate readings that are outside the normal range. The number and percentage of participants who experienced significant pulse rate change from baseline will be summarized by dose level

Evaluate blood pressure that is out of normal range and changes in blood pressure as compared to baseline
From baseline until end of study treatment or study completion (approximately 2 years)

Identify systolic and diastolic readings that are outside the normal range. The number and percentage of participants who experienced significant blood pressure change from baseline will be summarized by dose level

To evaluate heart rate corrected QT interval and changes in corrected QT interval as compared to baseline
From baseline until end of study treatment or study completion (approximately 2 years)

Determine the effect of the drug on QT prolongation. The number and percentage of participants who experienced QT interval prolongation will be summarized by dose level

To evaluate the preliminary antitumor activity of PF-07104091 as a single agent and in combination with palbociclib and in combination with letrozole or fulvestrant or fulvestrant alone by objective response rate (ORR) in dose expansion
From baseline through disease progression or study completion (approximately 2 years)

Percentage of participants with a best overall response of complete response (CR) or partial response (PR) using RECIST 1.1

Secondary Endpoints

Maximum plasma concentration (Cmax) of PF-07104091 after a single dose and multiple dose
Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Time to maximum plasma concentration (Tmax) of PF-07104091 after a single dose and multiple dose
Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Area under the concentration versus time curve from time zero to the last quantifiable time point prior to the next dose (AUClast) of PF-07104091
Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
PF-07104091EXPERIMENTALCDK2 monotherapy dose escalation
PF-07104091 + palbociclib + fulvestrantEXPERIMENTALCDK2 + palbociclib + fulvestrant
PF-07104091 + palbociclib + letrozoleEXPERIMENTALCDK2 + palbociclib + letrozole
PF-07104091 monotherapy dose expansion (SCLC)EXPERIMENTALPF-07104091 monotherapy dose expansion (SCLC)
PF-07104091 monotherapy dose expansion (ovarian)EXPERIMENTALPF-07104091 monotherapy dose expansion (ovarian)
PF-07104091 + fulvestrant (post CDK4/6) dose expansionEXPERIMENTALPF-07104091 + fulvestrant (post CDK4/6) dose expansion
PF-07104091 + fulvestrant (post CDK 4/6) dose escalationEXPERIMENTALCDK2+ fulvestrant (post CDK 4/6) dose escalation

Interventions

NameTypeDescription
PF-07104091 monotherapy dose escalationDRUGPF-07104091 will be administered orally
PF-07104091 + palbociclib + fulvestrantDRUGPF-07104091 will be administered orally in combination with palbociclib and fulvestrant
PF-07104091 + palbociclib + letrozoleDRUGPF-07104091 will be administered orally in combination with palbociclib and letrozole
PF-07104091 monotherapy dose expansion (ovarian)DRUGPF-07104091 will be administered orally
PF-07104091 monotherapy dose expansion (SCLC)DRUGPF-07104091 will be administered orally
PF-07104091 + Fulvestrant (post CDK4/6)DRUGPF-07104091 will be administered orally in combination with fulvestrant
PF-0704091 + Fulvestrant (post CDK4/6)DRUGPF-07104091 + fulvestrant (post 4/6) dose expansion
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites22

Inclusion Criteria: * Participants with HR-positive HER2-negative advanced or metastatic breast cancer (received at least two prior lines in the advanced or metastatic setting including one prior line of combined CDK4/6 inhibitor and endocrine therapy and no more than two prior lines of cytotoxic c...

Countries:United StatesArgentinaBulgariaChina
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Competitive Landscape -Small Cell Lung Cancer 3 trials

Top 1 of 2 competitors

CompanyTickerTrialsLead PhaseDrugs
Amgen Inc.AMGN1PHASE3Tarlatamab
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Frequently asked questions about PF-07104091

What is PF-07104091?

PF-07104091 is an investigational small molecule oncology drug developed by Pfizer, Inc. (ticker PFE). It is being studied as a single agent and in combination therapy for solid tumors, including small cell lung cancer, ovarian cancer, and breast cancer. It is currently in Phase 2 clinical development and has not been approved for any indication.

What is PF-07104091 used for in small cell lung cancer?

PF-07104091 is being evaluated for the treatment of small cell lung cancer, along with ovarian cancer and breast cancer, in a Phase 2 clinical trial. It is an investigational therapy and is not approved for use in small cell lung cancer or any other indication.

Who makes PF-07104091?

PF-07104091 is developed by Pfizer, Inc., which trades on the New York Stock Exchange under the ticker PFE. Pfizer is the sponsor of the clinical program evaluating the drug as a single agent and in combination therapy across several tumor types.

What phase is PF-07104091 in?

PF-07104091 is in Phase 2 clinical development. The program consists of one active trial that is no longer recruiting participants. The drug remains investigational and has not received FDA approval for any indication.

What clinical trials is PF-07104091 in?

PF-07104091 is being studied in the Phase 2 trial NCT04553133, titled "PF-07104091 as a Single Agent and in Combination Therapy." The trial has an enrollment of 157 participants and is active but not recruiting. It is being conducted in the United States, Argentina, Bulgaria, and China.

Is PF-07104091 the same as PF-0704091?

Yes, PF-0704091 is an alternative name used for PF-07104091. The drug is also referenced in combination regimens such as PF-07104091 plus PF-07220060 plus fulvestrant, and PF-0704091 plus fulvestrant in post-CDK4/6 settings, as well as PF-07104091 monotherapy dose escalation.