辉瑞新药利特昔替尼的功效与作用？

The efficacy and functions of Pfizer's new drug ritexitinib mainly include inhibiting JAK kinase, regulating immune response, promoting hair growth, improving quality of life, etc. Ritexitinib should be used under the guidance of a doctor and should not be used on your own.

Pfizer’s new drug ritexitinib

is a drug produced by Pfizer Inc., headquartered in New York, USA. On June 23, 2023, Pfizer announced that the U.S. FDA approved the marketing of Ritlecitinib as a once-a-day oral therapy for the treatment of severe alopecia areata in patients over 12 years old. On June 26, 2023, the drug was approved in Japan for the treatment of alopecia areata (limited to widespread and refractory hair loss).

Mechanism of action of ritixitinib

Ritexitinib can block the signaling and immune cell activity induced by cytokines mediated by JAK3-dependent receptors by inhibiting tyrosine kinases in JAK3 and TEC kinase families, helping to reduce the immune system's attack on hair follicles, thereby promoting hair regeneration and preventing further hair loss.

Efficacy and effects of Pfizer's new drug ritexitinib

1. Inhibition of JAK kinase: ritixitinib blocks the cytokine-induced signaling mediated by JAK3-dependent receptors by irreversibly inhibiting Janus kinase 3 (JAK3) and the tyrosine kinase (TEC) kinase family expressed in hepatocellular carcinoma.

2. Regulate immune response: Ritexitinib can reduce the immune system’s attack on hair follicles, which is a key factor in the pathogenesis of alopecia areata. By modulating the immune response, ritexitinib helps reduce inflammation and promote hair regrowth.

3. Promote hair growth: In clinical trials, ritexitinib has been shown to improve the scalp hair loss score (SALT) of patients with alopecia areata and promote hair regeneration and increase in density.

4. Improve quality of life: By reducing the symptoms of alopecia areata, ritexitinib helps improve patients' self-esteem and social functions, thereby improving quality of life.

Efficacy of Pfizer's new drug ritexitinib in the treatment of alopecia areata

In a randomized, double-blind, multinational Phase 2b/3 trial, adults aged ≥18 years and adolescents aged 12-17 years with alopecia areata and ≥50% scalp hair loss (including alopecia totalis and alopecia universalis), with a maximum duration of current hair loss episodes ≤10 years, were included.

Patients were randomly assigned to receive rituxitinib 200 mg for 4 weeks, then 50 mg (n=132), ritixitinib 200 mg for 4 weeks, then 30 mg (n=130), ritixitinib 50 mg (n=130), ritixitinib 30 mg (n=130), or ritixitinib 10 mg (n=63), placebo for 24 weeks, then ritixitinib 200 mg for 4 weeks, then ritixitinib 50 mg (n=65), or placebo for 24 weeks, then ritixitinib 50 mg (n=66).

Randomization stratified according to scalp alopecia and age. Study drug was administered orally once daily with a placebo-controlled period lasting 24 weeks and an extension period lasting 24 weeks. During the extension period, patients randomized to receive placebo were switched to ritixitinib, while patients randomized to receive rituxitinib continued on maintenance doses.

At week 24, in the ritixitinib 200+50mg and 200+30mg groups, the proportions of patients who achieved the primary endpoint SALT score ≤20 (i.e. scalp hair loss ≤20%) were 31%, 22%, 23%, 14% and 2% respectively, while the proportion in the combined placebo group was 2%. Except for the 10 mg group, the differences between ritexitinib and placebo were significant.

The proportion of patients who met the more stringent key secondary endpoint of SALT score ≤10 (ie, scalp hair loss ≤10%) were 22%, 13%, 14%, 11%, 2% in the ritixitinib group and 2% in the placebo group. Similarly, except for the 10 mg group, the differences between ritexitinib and placebo were also significant.

The long-term efficacy of ritexitinib in treating alopecia areata. By week 48 (i.e., the end of the 24-week extension period), the proportions of patients with SALT scores ≤20 in the ritixitinib 200+50 mg and 200+30 mg groups were 40%, 34%, 43%, and 31% respectively.

Summary

Pfizer's new drug ritexitinib has shown good efficacy in the treatment of alopecia areata, but the drug can cause adverse reactions such as headache, diarrhea, acne, rash, urticaria, folliculitis, etc., so it needs to be taken according to the doctor's advice. Keep your scalp clean during medication, wash your hair regularly, avoid scratching it with your hands, and avoid using irritating shampoos.

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