Ritlecitinib

Ritlecitinib (brand name Litfulo) is used to treat severe alopecia areata in adults and adolescents 12 years and older. Alopecia areata is an autoimmune condition in which the immune system attacks hair follicles and causes hair to fall out. Ritlecitinib is an oral prescription JAK inhibitor taken once daily and is sold under the brand name Litfulo.

Ritlecitinib works by selectively blocking two types of signaling proteins involved in this autoimmune attack: Janus kinase 3 (JAK3) and the TEC family of kinases. By interrupting these signals, it reduces the number of inflammatory cells targeting the hair follicles, which allows hair to regrow. Ritlecitinib belongs to the drug class called kinase inhibitors.

Ritlecitinib gained FDA approval on June 23, 2023, under the brand name Litfulo, and no generic version is currently available. Approval was based on the ALLEGRO clinical trial (NCT03732807), which measured scalp coverage using the Severity of Alopecia Tool (SALT). At 24 weeks, the trial reported:

• 23% of patients taking ritlecitinib achieved 80% or more scalp hair coverage, compared with 1.6% on placebo
• 13.4% achieved 90% or more scalp hair coverage, compared with 1.5% on placebo
• Significant eyebrow and eyelash regrowth also occurred.

Ritlecitinib is a JAK inhibitor and carries a Boxed Warning for serious infections, mortality, cancer, major adverse cardiovascular events, and thrombosis.

• Serious infections. Ritlecitinib affects your immune system and can lower the ability of your immune system to fight infections. Some people have had serious infections while taking ritlecitinib or other similar medicines, including tuberculosis (TB), and infections caused by bacteria, fungi, or viruses that can spread throughout the body and have been hospitalized. Some people taking similar medicines to ritlecitinib have died from these infections. Your healthcare provider should test you for TB before starting treatment with ritlecitinib. Your healthcare provider should watch you closely for signs and symptoms of TB during treatment with ritlecitinib.

You should not start taking ritlecitinib if you have any kind of infection unless your healthcare provider tells you it is okay.

You may be at a higher risk of developing shingles (herpes zoster).

Before starting ritlecitinib, tell your healthcare provider if you:

• are being treated for an infection. have an infection that has not gone away, or that keeps coming back. have diabetes, chronic lung disease, HIV, or a weak immune system. have TB or have been in close contact with someone with TB. have had shingles (herpes zoster). have had hepatitis B or hepatitis C. live or have lived or have traveled to certain parts of the country (such as the Ohio and Mississippi River valleys and the Southwest) where there is an increased chance for getting certain kinds of fungal infections. These infections may happen or become more severe if you use ritlecitinib. Ask your healthcare provider if you do not know if you have lived in an area where these infections are common. think you have an infection or have symptoms of an infection such as: fever, sweating, or chills muscle aches cough or shortness of breath blood in your phlegm weight loss warm, red, or painful skin or sores on your body diarrhea or stomach pain burning when you urinate or urinating more often than usual feeling very tired.

After starting ritlecitinib, call your healthcare provider right away if you have any symptoms of an infection. Ritlecitinib can make you more likely to get infections or make any infections that you have worse. If you get a serious infection, your healthcare provider may stop treatment with ritlecitinib until your infection is controlled.

• Increased risk of death in people 50 years of age and older who have at least 1 heart disease (cardiovascular) risk factor and are taking a medicine in the class of medicines called Janus kinase (JAK) inhibitors. Ritlecitinib is a kinase inhibitor medicine.
• Cancer and immune system problems. Ritlecitinib may increase your risk of certain cancers by changing the way your immune system works. Lymphoma and other cancers, including skin cancers, can happen in people taking ritlecitinib. People taking a medicine in the class of medicines called JAK inhibitors have a higher risk of certain cancers, including lymphoma and lung cancer, especially if you are a current or past smoker. Follow your healthcare provider's advice about having your skin checked for skin cancer during treatment with ritlecitinib.

Tell your healthcare provider if you have ever had any type of cancer.

• Increased risk of major cardiovascular events such as heart attack, stroke, or death in people 50 years of age and older who have at least 1 heart disease (cardiovascular) risk factor and are taking a medicine in the class of medicines called JAK inhibitors, especially if you are a current or past smoker. Get emergency help right away if you have any symptoms of a heart attack or stroke while using ritlecitinib, including: discomfort in the center of your chest that lasts for more than a few minutes, or that goes away and comes back severe tightness, pain, pressure, or heaviness in your chest, throat, neck, or jaw pain or discomfort in your arms, back, neck, jaw, or stomach shortness of breath with or without chest discomfort breaking out in a cold sweat nausea or vomiting feeling lightheaded weakness in one part or on one side of your body slurred speech
• Blood clots. Blood clots in the veins of your legs (deep vein thrombosis, DVT), lungs (pulmonary embolism, PE), or eyes can happen in some people taking ritlecitinib. This may be life-threatening. Blood clots in the veins of the legs (deep vein thrombosis, DVT) and lungs (pulmonary embolism, PE) have happened more often in people who are 50 years of age and older with at least 1 heart disease (cardiovascular) risk factor taking a medicine in the class of medicines called JAK inhibitors. Tell your healthcare provider if you have had blood clots in the past. Stop taking ritlecitinib and get medical help right away if you have any signs and symptoms of blood clots during treatment with ritlecitinib, including: swelling, pain, or tenderness in one or both legs sudden, unexplained chest or upper back pain shortness of breath or difficulty breathing changes in vision, especially in one eye only
• Allergic reactions. Symptoms that may mean you are having an allergic reaction have been seen during treatment with ritlecitinib. Some of these reactions were serious. Stop taking ritlecitinib and get emergency medical help right away if you have symptoms of an allergic reaction, including: hives rash trouble breathing feeling faint or dizzy swelling of your lips, tongue, or throat.
• Low blood sugar in people with diabetes. If you have diabetes, your healthcare provider may instruct you to check your blood sugar levels more often during treatment with ritlecitinib. Call your healthcare provider if you have any problems with low blood sugar (hypoglycemia).
• Changes in certain laboratory test results. Your healthcare provider should do blood tests before you start taking ritlecitinib and during treatment to check for the following: low lymphocyte count. Lymphocytes are white blood cells that help the body fight off infections. low platelet count. Platelets help form clots and stop or prevent bleeding. elevated liver enzymes. Liver enzymes help to tell if your liver is functioning normally. Elevated liver enzymes may indicate that your healthcare provider needs to do additional tests on your liver. increased creatine phosphokinase (CPK). Increased CPK levels in the blood are common with ritlecitinib and can also be severe.

You should not take ritlecitinib if your lymphocyte counts or platelet counts are too low or your liver tests are too high. Your healthcare provider may stop your ritlecitinib treatment for a period of time if needed because of changes in these blood test results.

See "What are the possible side effects of ritlecitinib?" for more information about side effects.

• Take ritlecitinib exactly as your healthcare provider tells you to take it.
• Take ritlecitinib 1 time each day, with or without food.
• Swallow ritlecitinib capsules whole. Do not crush, split, or chew the capsules.
• If you miss a dose of ritlecitinib, take the missed dose as soon as you remember. If it is less than 8 hours before your next scheduled dose of ritlecitinib, skip the missed dose and take the next dose at your usual time.

If you take too much ritlecitinib, call the Poison Control Center at 1-800-222-1222 or go to the nearest hospital emergency room right away.

Before taking ritlecitinib, tell your healthcare provider about all of your medical conditions, including if you:

• See "What is the most important information I should know about ritlecitinib?"
• have an infection
• are a current or past smoker
• have had a heart attack, other heart problems, or stroke
• have liver problems
• have diabetes
• have low platelet counts or white blood cell counts
• have recently received or are scheduled to receive an immunization (vaccine). People who take ritlecitinib should not receive live vaccines during treatment or right before starting treatment with ritlecitinib.
• are pregnant or plan to become pregnant. It is not known if ritlecitinib will harm your unborn baby. Females who can become pregnant: Tell your healthcare provider if you are pregnant or plan to become pregnant during treatment with ritlecitinib. There is a pregnancy registry for people who take ritlecitinib during pregnancy. Report pregnancies to Pfizer Inc. at 1-877-390-2940.
• are breastfeeding or plan to breastfeed. It is not known if ritlecitinib passes into your breast milk. Do not breastfeed during treatment with ritlecitinib and for 14 hours after your last dose of ritlecitinib. Talk to your healthcare provider about the best way to feed your baby during treatment with ritlecitinib.

It is not known if ritlecitinib is safe and effective in children under 12 years of age.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Ritlecitinib and other medicines may affect each other, causing side effects.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist whenever you get a new medicine.

Serious side effects

Ritlecitinib may cause serious side effects, including:

• See "What is the most important information I should know about ritlecitinib?", above.

Common side effects

The most common side effects of ritlecitinib include:

• headache
• diarrhea
• fever
• eczema
• hives
• inflamed hair pores (folliculitis)
• acne
• rash
• dizziness
• shingles
• decreased red blood cell counts
• mouth sores, redness and swelling of the lining of your mouth.

These are not all the possible side effects of ritlecitinib. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to Pfizer at 1-800-438-1985.

• Store ritlecitinib at room temperature between 68°F and 77°F (20°C and 25°C).
• Keep ritlecitinib in the original package.
• The ritlecitinib bottle has a child-resistant closure and contains a canister with a drying agent (desiccant). Do not eat the desiccant.

Keep ritlecitinib and all medicines out of the reach of children.

Active ingredient: ritlecitinib

Inactive ingredients: crospovidone, glyceryl dibehenate, lactose monohydrate, microcrystalline cellulose, and hypromellose (HPMC) capsule shells. The yellow/blue, opaque capsule shells contain Brilliant blue FCF - FD&C Blue, hypromellose, titanium dioxide, and yellow iron oxide.

Ritlecitinib is manufactured under the brand name Litfulo and distributed by Pfizer Labs, Division of Pfizer Inc., New York, NY 10001.