PF-06651600 (ritlecitinib) has been evaluated in numerous Phase I, Phase II, and Phase III clinical trials focusing on autoimmune and dermatological conditions—including alopecia areata, nonsegmental vitiligo, rheumatoid arthritis, and keloids—alongside pharmacokinetic evaluations in healthy volunteers and individuals with hepatic or renal impairment. Sponsored primarily by Pfizer alongside academic institutions such as the Icahn School of Medicine at Mount Sinai and Centre Hospitalier Universitaire de Nice, these trials span completed, active recruiting, active non-recruiting, and terminated statuses.
| NCT Number | Recruitment | Conditions | Sponsor/Collaborators | Start Date | Phases |
|---|---|---|---|---|---|
| NCT07029828 | RECRUITING | Severe Alopecia Areata |
Pfizer |
2025-09-10 | PHASE3 |
| NCT07152626 | RECRUITING | Vitiligo |
Centre Hospitalier Universitaire de Nice |
2026-03-12 | PHASE2 |
| NCT07733765 | RECRUITING | Alopecia Areata |
Pfizer |
2026-07-30 | PHASE3 |
| NCT06873945 | RECRUITING | Alopecia Areata |
Pfizer |
2025-04-01 | PHASE3 |
| NCT06373458 | RECRUITING | Keloid |
Icahn School of Medicine at Mount Sinai |
2024-08-13 | PHASE2 |
| NCT06072183 | ACTIVE_NOT_RECRUITING | Stable Nonsegmental Vitiligo; Active Nonsegmental Vitiligo |
Pfizer |
2023-11-08 | PHASE3 |
| NCT06163326 | ACTIVE_NOT_RECRUITING | Vitiligo |
Pfizer |
2024-01-19 | PHASE3 |
| NCT07219615 | RECRUITING | Chronic Spontaneous Urticaria |
Pfizer |
2025-10-30 | PHASE2 |
| NCT07228390 | ACTIVE_NOT_RECRUITING | Hidradenitis Suppurativa |
Pfizer |
2025-11-13 | PHASE2 |
| NCT07029711 | ACTIVE_NOT_RECRUITING | Severe Alopecia Areata |
Pfizer |
2025-07-31 | PHASE3 |
| NCT05743244 | ACTIVE_NOT_RECRUITING | Diabetes Mellitus, Type 1 |
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) |
2023-10-19 | PHASE2 |
| NCT06795373 | WITHDRAWN | Chronic Spontaneous Urticaria; CSU |
Ahuva D Cices |
2025-12-31 | PHASE2 |
| NCT05583526 | COMPLETED | Stable Nonsegmental Vitiligo; Active Nonsegmental Vitiligo |
Pfizer |
2022-12-01 | PHASE3 |
| NCT05636293 | COMPLETED | Celiac Disease |
Massachusetts General Hospital |
2023-03-01 | PHASE2 |
| NCT05879458 | TERMINATED | CTCL; Mycosis Fungoides; Sezary Syndrome |
Icahn School of Medicine at Mount Sinai |
2023-05-17 | PHASE2 |
| NCT05549934 | COMPLETED | Cicatricial Alopecia |
Emma Guttman |
2022-12-15 | PHASE2 |
| NCT06369454 | COMPLETED | Healthy Volunteers |
Pfizer |
2024-05-03 | PHASE1 |
| NCT04006457 | COMPLETED | Alopecia Areata |
Pfizer |
2019-07-18 | PHASE3 |
| NCT06172348 | COMPLETED | Healthy Volunteers |
Pfizer |
2024-02-01 | PHASE1 |
| NCT03395184 | COMPLETED | Crohn's Disease |
Pfizer |
2018-02-02 | PHASE2 |
| NCT05650333 | COMPLETED | Alopecia Areata |
Pfizer |
2023-03-02 | PHASE1 |
| NCT05852340 | COMPLETED | Healthy Volunteers; Adult; Pharmacokinetics |
Pfizer |
2023-05-09 | PHASE1 |
| NCT04413617 | COMPLETED | Rheumatoid Arthritis |
Pfizer |
2020-07-29 | PHASE2 |
| NCT05128058 | COMPLETED | Healthy |
Pfizer |
2021-10-22 | PHASE1 |
| NCT05097716 | COMPLETED | Healthy Volunteers |
Pfizer |
2021-11-02 | PHASE1 |
| NCT04517864 | TERMINATED | Alopecia Areata |
Pfizer |
2020-09-15 | PHASE2 |
| NCT05040295 | COMPLETED | Healthy Participants |
Pfizer |
2021-09-10 | PHASE1 |
| NCT04390776 | COMPLETED | Healthy Participants |
Pfizer |
2020-09-28 | PHASE1 |
| NCT02958865 | COMPLETED | Ulcerative Colitis |
Pfizer |
2017-02-03 | PHASE2 |
| NCT04655040 | COMPLETED | Healthy Participants |
Pfizer |
2020-12-18 | PHASE1 |
| NCT03715829 | COMPLETED | Active Non-segmental Vitiligo |
Pfizer |
2018-11-26 | PHASE2 |
| NCT03732807 | COMPLETED | Alopecia Areata |
Pfizer |
2018-12-03 | PHASE2; PHASE3 |
| NCT04634565 | COMPLETED | Healthy Participants |
Pfizer |
2020-10-15 | PHASE1 |
| NCT04266509 | COMPLETED | Healthy Volunteers |
Pfizer |
2020-06-25 | PHASE1 |
| NCT04390776 | Completed | Healthy Participants |
Pfizer |
2020-09-28 | Phase 1 |
| NCT04355845 | COMPLETED | Healthy Volunteers |
Pfizer |
2020-06-15 | PHASE1 |
| NCT04266509 | Completed | Healthy Volunteers |
Pfizer |
2020-06-25 | Phase 1 |
| NCT04037865 | TERMINATED | Renal Impairment |
Pfizer |
2019-08-19 | PHASE1 |
| NCT04016077 | COMPLETED | Hepatic Impairment; Healthy Participants |
Pfizer |
2019-07-19 | PHASE1 |
| NCT04092595 | COMPLETED | Healthy Volunteers |
Pfizer |
2019-09-26 | PHASE1 |
| NCT04018274 | COMPLETED | Healthy |
Pfizer |
2019-08-09 | PHASE1 |
| NCT04004663 | COMPLETED | Healthy Volunteers |
Pfizer |
2019-07-15 | PHASE1 |
| NCT04037865 | Terminated | Renal Impairment |
Pfizer |
2019-08-19 | Phase 1 |
| NCT03929510 | COMPLETED | Healthy Volunteers |
Pfizer |
2019-04-23 | PHASE1 |
| NCT04016077 | Completed | Hepatic Impairment|Healthy Participants |
Pfizer |
2019-07-19 | Phase 1 |
| NCT04004663 | Completed | Healthy Volunteers |
Pfizer |
2019-07-15 | Phase 1 |
| NCT02974868 | COMPLETED | Alopecia Areata |
Pfizer |
2016-12-15 | PHASE2 |
| NCT03916393 | COMPLETED | Healthy Participants |
Pfizer |
2019-04-15 | PHASE1 |
| NCT03827668 | COMPLETED | Healthy |
Pfizer |
2019-02-07 | PHASE1 |
| NCT03821493 | COMPLETED | Healthy Participants |
Pfizer |
2019-02-21 | PHASE1 |
| NCT03762928 | COMPLETED | Healthy Subjects |
Pfizer |
2018-12-07 | PHASE1 |
| NCT03608241 | COMPLETED | Healthy Females |
Pfizer |
2018-09-21 | PHASE1 |
| NCT02969044 | COMPLETED | Rheumatoid Arthritis |
Pfizer |
2016-12-20 | PHASE2 |
| NCT03232905 | COMPLETED | Healthy |
Pfizer |
2017-08-30 | PHASE1 |
| NCT02684760 | COMPLETED | Healthy |
Pfizer |
2016-02 | PHASE1 |
| NCT02309827 | COMPLETED | Healthy |
Pfizer |
2014-12 | PHASE1 |
(data from https://clinicaltrials.gov, updated on 2026-04-28)
Check the
PF-06651600 (Ritlecitinib)
product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.
Mechanism and Biochemical Profile
Appendix RUO and cGMP Quality Standards
| Quality Dimension | RUO (Research Use Only) | cGMP (Current Good Manufacturing Practice) |
|---|---|---|
| Clinical Applicability | Prohibited in human clinical trials or medical diagnostics. | Mandatory for human clinical trials (Phase I–III) and therapies. |
| Regulatory Status | Non-regulated grade; exempt from drug manufacturing laws. | Legally enforced by health authorities (e.g., FDA, EMA, NMPA). |
| Facility Environment | Unclassified analytical or research laboratories. | Validated Cleanrooms (ISO Class 5–8) with continuous monitoring. |
| Quality Control | Basic purity and activity testing. | Rigorous safety release testing (Sterility, Endotoxin, Mycoplasma). |
| Process Validation | Basic equipment calibration; no process validation required. | Full qualification (IQ/OQ/PQ) and complete batch records. |
| Quality Assurance | Vendor self-declared without required formal QMS. | Mandatory QA/QC unit, Change Control, CAPA, and vendor audits. |
| Regulatory Impact | High risk of IND rejection if used as a critical raw material. | Required for IND/NDA filings, supported by Drug Master Files (DMF). |
Footnotes
Regulatory Note: Governed by FDA (21 CFR Parts 210/211/312), EMA (EudraLex Vol 4), ICH Guidelines (E6/Q7/Q9/Q10), and compendial standards (USP <71>/<85>/<1043>).
- PF-06651600 (Ritlecitinib) Solubility in DMSO
- PF-06651600 (Ritlecitinib) Stock Solution
- PF-06651600 (Ritlecitinib) Storage
- PF-06651600 (Ritlecitinib) Stability
- PF-06651600 (Ritlecitinib) Molecular Weight
- PF-06651600 (Ritlecitinib) SMILES
- PF-06651600 (Ritlecitinib) CAS Number
- PF-06651600 (Ritlecitinib) Chemical Structure (2D and 3D)
- PF-06651600 (Ritlecitinib) SDS｜MSDS
Note: Technical data last updated: Sep 1, 2026.