Ritlecitinib

Generic Name: Ritlecitinib

Brand Names: Litfulo

Drug Type: Small Molecule

Chemical Formula: C_₁₅H_₁₉N_₅O

CAS Number: 1792180-81-4

Unique Ingredient Identifier: 2OYE00PC25

Background: Ritlecitinib (PF-06651600) is a highly selective inhibitor of Janus kinase 3 (JAK3) and the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family. In June 2023, it was approved by the FDA for the treatment of severe alopecia areata in adults and adolescents 12 years and older. It was further approved by the EMA in September 2023. Ritlecitinib is administered orally and is the first member of its class.

Ritlecitinib binds covalently to Cys-909 of JAK3, a site where other JAK isoforms have a serine residue. This makes ritlecitinib a highly selective and irreversible JAK3 inhibitor. Other kinases have a cysteine at a position equivalent to Cys-909 in JAK3, and several of them belong to the TEC kinase family. It has been suggested that the dual activity of ritlecitinib toward JAK3 and the TEC kinase family block cytokine signaling as well as the cytolytic activity of T cells, both implicated in the pathogenesis of alopecia areata.

Indication: Ritlecitinib is indicated for the treatment of severe alopecia areata in adults and adolescents 12 years and older. It is not recommended for use in combination with other JAK inhibitors, biologic immunomodulators, cyclosporine or other potent immunosuppressants.

Associated Conditions: Severe Alopecia Areata (AA)

Clinical Trials

Ritlecitinib in CTCL

Phase 2

Active, not recruiting

Conditions: CTCL
Sezary Syndrome
Mycosis Fungoides

Interventions: Drug: Ritlecitinib

First Posted Date: 2023-05-30

Last Posted Date: 2025-05-01

Lead Sponsor: Icahn School of Medicine at Mount Sinai

Target Recruit Count: 7

Registration Number: NCT05879458

Locations: 🇺🇸
Icahn School of Medicine at Mount Sinai, New York, New York, United States

A Study to Assess Two Forms of The Study Medicine (Ritlecitinib) in Healthy Adult Participants

Phase 1

Completed

Conditions: Pharmacokinetics
Adult
Healthy Volunteers

Interventions: Drug: Ritlecitinib

First Posted Date: 2023-05-10

Last Posted Date: 2024-10-16

Lead Sponsor: Pfizer

Target Recruit Count: 12

Registration Number: NCT05852340

Locations: 🇧🇪
Pfizer Clinical Research Unit - Brussels, Brussels, Bruxelles-capitale, Région DE, Belgium

Janus Kinase (JAK) Inhibitors to Preserve C-Peptide Production in New Onset Type 1 Diabetes (T1D)

Phase 2

Recruiting

Conditions: Diabetes Mellitus, Type 1

Interventions: Drug: Abrocitinib 200 MG Oral Tablet
Drug: Ritlecitinib
Drug: Placebo

First Posted Date: 2023-02-24

Last Posted Date: 2024-10-21

Lead Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Target Recruit Count: 78

Registration Number: NCT05743244

Locations: 🇺🇸
Children's Hospital Orange County, Orange, California, United States
🇺🇸
Stanford University, Palo Alto, California, United States
🇺🇸
University of California- San Francisco, San Francisco, California, United States

and more 17 locations

A Study to Learn About the Study Medicine (Called Ritlecitinib) For the Potential Treatment of Severe Alopecia Areata (AA) In Children 6 To Less Than 12 Years of Age

Phase 1

Completed

Conditions: Alopecia Areata

Interventions: Drug: Ritlecitinib 20 mg

First Posted Date: 2022-12-14

Last Posted Date: 2024-10-07

Lead Sponsor: Pfizer

Target Recruit Count: 15

Registration Number: NCT05650333

Locations: 🇺🇸
Nicklaus Children's Hospital, Miami, Florida, United States
🇺🇸
Texas Dermatology and Laser Specialists, San Antonio, Texas, United States
🇺🇸
Dawes Fretzin Clinical Research Group, LLC, Indianapolis, Indiana, United States

and more 6 locations

Double Blind, Placebo-controlled Trial to Establish Safety and Efficacy of Ritlecitinib in Celiac Disease Patients in Remission

Phase 2

Recruiting

Conditions: Celiac Disease

Interventions: Drug: Ritlecitinib
Drug: Placebo
Other: Gluten

First Posted Date: 2022-12-05

Last Posted Date: 2025-02-20

Lead Sponsor: Massachusetts General Hospital

Target Recruit Count: 40

Registration Number: NCT05636293

Locations: 🇺🇸
Massachusetts General Hospital, Boston, Massachusetts, United States

A 52-Week Study of Ritlecitinib Oral Capsules in Adults and Adolescents With Nonsegmental Vitiligo (Active and Stable) Tranquillo

Phase 3

Active, not recruiting

Conditions: Stable Nonsegmental Vitiligo
Active Nonsegmental Vitiligo

Interventions: Drug: Placebo
Drug: Ritlecitinib

First Posted Date: 2022-10-17

Last Posted Date: 2025-02-27

Lead Sponsor: Pfizer

Target Recruit Count: 581

Registration Number: NCT05583526

Locations: 🇨🇳
The First Hospital of China Medical University/Dermatology and STD Department, Shenyang, Liaoning, China
🇨🇳
Huashan Hospital Fudan University, Shanghai, Shanghai, China
🇪🇸
Hospital Universitario de Gran Canaria Doctor Negrín, Las Palmas de Gran Canaria, Canarias, Spain

and more 107 locations