A Phase 1/2 interventional study of PF-08154225 in Systemic Lupus Erythematosus, Rheumatoid Arthritis and Idiopathic Inflammatory Myositis, sponsored by Pfizer. Not yet recruiting. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-10-01.
Sponsored by Pfizer · Phase 1/2, Interventional, and Treatment
The purpose of this study is to learn about the safety and effects of the study medication called PF-08154225 for the potential treatment of autoimmune diseases. An autoimmune disease is a condition that makes a person's immune system attack its healthy cells by mistake. This study is particularly looking at autoimmune diseases called as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Idiopathic Inflammatory Myositis (IIM) or Systemic Sclerosis (SSc).
This study is divided into 3 parts: Part 1a, Part 1b and Part 2. Parts 1a and 1b are seeking participants with Systemic Lupus Erythematosus (SLE) or Rheumatoid Arthritis and Part 2 with also Idiopathic Inflammatory Myositis (IIM) or Systemic Sclerosis (SSc).
Participants can take part only in one part of the study.
All participants in this study will receive PF-08154225 at the study clinic. In Part 1a participants will receive single administration of PF-08154225 after which they will be observed at the study clinic during regular visits through week 16 or longer.
In Part 1b the participants will receive multiple administration of PF-08154225 after which they will be monitored in similar a manner as in Part 1a through week 24 or longer.
In Part 2 participants will receive multiple administrations of PF-08154225. After the last injection they will be monitored for safety through week 52 or longer.
This clinical trial consists of Part I and Part II. Phase I consists of dose escalation. The main goal of dose escalation is to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of PF-08154225 in participants with Systemic Lupus Erythematosus (SLE) or Rheumatoid Arthritis (RA), and the main goal of Part II is to assess effects of PF-08154225 on the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy in participants with SLE or RA or IIM or SSc.
1,207 studies on the registry are indexed under Lupus Erythematosus, Systemic; 405 are open to participants now.
This study's planned enrollment of 54 is close to the median of 52 across 876 interventional studies indexed under Lupus Erythematosus, Systemic.
Browse Lupus Erythematosus, Systemic studies →Pfizer is the lead sponsor of 3,334 studies on the registry; 149 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 391 (65%) have results posted.
Counted across the registry records on this site, refreshed daily.
Select Inclusion Criteria
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Single and multiple dose cohorts. Part 1: Participants will receive different target doses of PF-08154225 in a single and multiple dose escalation stage to evaluate their safety, tolerability, Pharmacokinetic (PK), Pharmacodynamic (PD). Part 2: Participants will receive different doses of PF-08154225 in an open label single arm setting to evaluate their safety, tolerability, PK, PD and preliminary efficacy.
Drug: PF-08154225
immune-modulating agent
Incidence and severity of Treatment Emergent Adverse Event (AE) including protocol specified adverse event of special interest(AESI)
An AE is defined as any untoward medical event that occurs after a participant receives the investigational drug, which may be manifested as symptoms, signs, diseases, or laboratory abnormalities, but may not necessarily have a causal relationship with the investigational drug.
Time frame: From first dose through End of Study (up to Week 16 in Part 1a, Week 24 in Part 1b and Week 52 in Part2)
Dose Limiting Toxicity (DLT)
Time frame: During the DLT observation period (up to 22 days after the last dose)
Frequencies of abnormal safety laboratory tests, vital signs, ECGs.
Time frame: From first dose of study intervention through End of Study (up to Week 16 in Part 1a, Week 24 in Part 1b and Week 52 in Part 2)
Maximum Observed Serum Concentration (Cmax) of PF-08154225
Time frame: From first dose through the last pharmacokinetic assessment (up to Week 16 in Part 1a and up to Week 24 in Part 1b)
Time to Maximum Observed Serum Concentration (Tmax) of PF-08154225
Time frame: From first dose through the last pharmacokinetic assessment (up to Week 16 in Part 1a and up to Week 24 in Part 1b)
Area Under the Serum Concentration-Time Curve (AUC) of PF-08154225
AUClast, AUCinf, and AUCtau will be assessed as data permit.
Time frame: From first dose through the last pharmacokinetic assessment (up to Week 16 in Part 1a and up to Week 24 in Part 1b)
Circulating B-Cell Counts
Time frame: From first dose of study intervention through End of Study (Week 16 for Part 1a, week 24 for Part 1b and Week 52 for Part 2 or longer if extension of the follow up was needed
Participants With Anti-Drug Antibodies (ADAs) Against PF-08154225
Time frame: From first dose of study intervention through End of Study (Week 16 for Part 1a, Week 24 for Part 1b and Week 52 for Part2
Change From Baseline in Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) Score
Time frame: Baseline, Week 52
Change From Baseline in Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) Score
Time frame: Baseline, Week 52
Change From Baseline in Tender Joint Count
Time frame: Baseline, Week 52
Change From Baseline in Swollen Joint Count
Time frame: Baseline, Week 52
Change From Baseline in Physician Global Assessment Score
Time frame: Baseline, Week 52
Number of Participants With DORIS Remission
Time frame: Up to Week 52
Number of Participants With Lupus Low Disease Activity State (LLDAS)
Time frame: Up to Week 52
Number of Participants With SLE Responder Index-4 (SRI-4) Response
Time frame: Up to Week 52
Number of Participants With Disease Flare
Time frame: Up to Week 52
Change From Baseline in Disease Activity Score 28 Using C-Reactive Protein (DAS28-CRP)
Time frame: Baseline, Week 52
Change From Baseline in Simplified Disease Activity Index (SDAI)
Time frame: Baseline, Week 52
Participants Achieving American College of Rheumatology (ACR) Response Criteria
Time frame: Up to Week 52
Change From Baseline in Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) Score
Time frame: Baseline, Week 52
Change From Baseline in Manual Muscle Testing-8 (MMT-8) Score
Time frame: Baseline, Week 52
Change From Baseline in International Myositis Assessment and Clinical Studies Total Improvement Score (IMACS TIS)
Time frame: Baseline, Week 52
Change From Baseline in Modified Rodnan Skin Score (mRSS) in Participants With Systemic Sclerosis
Time frame: Baseline, Week 52
Participants Achieving Composite Response Index in Systemic Sclerosis (CRISS) Response
Time frame: Up to Week 52
No study locations are listed for this record.
Plan to share: 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.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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