Detailed instructions and medication guide for Ritexitinib (Lefenox)

1. Drug introduction and mechanism of action

Ritlecitinib (Ritlecitinib) is a new oral JAK3/TEC family kinase inhibitor, developed by Pfizer (Pfizer), with the trade name Litfulo. The drug was approved by the U.S. FDA in 2023 and is mainly used to treat moderate to severe alopecia areata (Alopecia) 12 years old and above. Areata) patients, it is the first JAK inhibitor drug to treat alopecia areata approved in adolescents. Compared with traditional immunosuppressants, Ritlecitinib can more accurately target immune signaling pathways, inhibit overactive T pathways related to natural killer cells, reduce immune attacks on hair follicles, thereby promoting hair growth and maintaining hair follicle function.

Its mechanism of action is mainly by inhibiting JAK3 and TEC kinase signals, blocking immune responses mediated by cytokines such as IL-15, IL-21, reducing the inflammatory microenvironment, and improving hair growth in patients with alopecia areata. In addition, its inhibition of targets such as JAK1/2 is weak, so clinically it has relatively reduced some serious adverse reactions related to systemic immunosuppression.

2. Indications, dosage forms, usage and dosage

1.Indications:

It is suitable for the treatment of patients 12 years old and above with moderate to severe alopecia areata, especially those whose scalp hair loss exceeds 50%, has a long course of disease and has poor response to other treatments.

Currently, the drug is also exploring its potential efficacy in other autoimmune diseases (such as atopic dermatitis, plaque psoriasis, etc.) in clinical studies, but these have not yet been included in the official indications.

2.Dosage forms and specifications:

Oral tablets, each tablet50mg, are commonly used specifications. In some areas, the 25mg strength is also available for dose adjustment.

3. Recommended usage and dosage:

The recommended dose for adults and adolescent patients 12 years old and above is 50 mg taken orally once a day. It can be taken with food or on an empty stomach.

It is not recommended that patients increase or decrease the dose on their own. If adjustments are needed, an experienced dermatologist or immunologist should make individual adjustments based on efficacy and tolerability.

In terms of treatment course, most patients can observe significant hair regrowth within about 24 weeks of taking the drug. Some patients require long-term maintenance treatment to prevent recurrence.

3. Adverse reactions and medication precautions

In clinical trials, Ritlecitinib was generally well tolerated, but similar to all JAK inhibitors, there is still a certain risk of adverse reactions. Common adverse reactions include:

Upper respiratory tract infection (such as cold, pharyngitis, etc.)

Mild gastrointestinal reactions such as headache, diarrhea, nausea, etc.

acneiform rash

Mildly elevated liver enzymes

Rare but serious adverse reactions that require attention include:

Serious infections (such as shingles, pneumonia, etc.)

Hematological abnormalities, such as leukopenia and lymphopenia

Severe liver function abnormalities

Rare cardiovascular events or thrombosis (associated with risk for the JAK family inhibitor class)

Therefore, it is recommended to conduct baseline screening before use, including testing for hepatitis B, hepatitis C, tuberculosis and other infectious diseases; regular monitoring of blood routine, liver and kidney function, and infection risk during treatment. If abnormal symptoms such as persistent high fever, cough, jaundice, and bleeding tendency occur, you should stop taking the medicine immediately and seek medical treatment.

In addition, it is not recommended for pregnant women, lactating women and those with a history of serious infections or tumors; for patients who are receiving live vaccines, medication should be postponed or combined use should be avoided to avoid increasing the risk of infection.

4. Medication Guide and Patient Management

1. Time and method of taking the medicine: Take orally at a fixed time every day, swallow the whole tablet, do not break it or chew it. It can be taken with meals to reduce gastrointestinal irritation but has little effect on absorption. If you miss a dose, you should take it as soon as possible, but there is no need to take it if it is close to the next dose.

2.Effectiveness evaluation: Most patients can experience initial hair growth around 12 weeks, but significant efficacy usually takes 24 weeks or more. Patients are advised to be patient and have regular follow-up visits to evaluate the treatment response.

3.Combined medication and contraindications: Avoid coadministration with strong CYP3A inducers or inhibitors to avoid affecting drug concentration. Use with caution in combination with other immunosuppressants or biological agents.

4. Treatment discontinuation and relapse management: If alopecia areata symptoms recur after stopping treatment, treatment can be restarted under the guidance of a doctor. Some patients may need to maintain low doses for a long time to consolidate the therapeutic effect.

In general, Ritlecitinib (Ritlecitinib) is a major advance in the treatment of alopecia areata, especially in adolescents, and has filled a clinical gap. Patients should follow medical advice during use, conduct regular follow-up monitoring, and reasonably evaluate efficacy and safety in order to maximize benefits and reduce medication risks.

Reference link:https://www.drugs.com