Amenamevir safe and effective treatment option for patients with herpes zoster

In the REWARD study, including 3098 Japanese patients with herpes zoster, the researchers found that amenamevir, a helicase–primase inhibitor, demonstrated high efficacy, with an overall improvement rate of 95.5%. Longer treatment duration, lower pain levels, and less severe cutaneous lesions were associated with higher improvement rates.

Amenamevir was approved for herpes zoster in Japan in 2017. Shinich Imafuku, Department of Dermatology, Fukuoka University, Fukuoka, Japan, and colleagues conducted a 1-month postmarketing observational study to assess the real-world efficacy (pain resolution and cutaneous improvement) and safety of AMNV in patients with herpes zoster.

Of the 3453 patients registered between 2018 and 2020, 3110 were included in the safety analyses. The mean age was 63.7 ± 17.5 years, and 57.9% of patients were aged ≥65 years. Most patients had moderate (41.0%) or mild (53.3%) cutaneous lesions.

The authors reported the following findings:

• 43.9%, 25.6%, and 12.5% of patients had pain at the levels of 1–3, 4–6, and 7–10 on the numerical rating scale.
• 30.0%, 27.2%, and 16.1% of patients were concomitantly treated with analgesics: acetaminophen, nonsteroidal anti-inflammatory drugs, and Ca2+ channel α 2δ ligands, respectively, and 10.6% were treated with topical antiherpetic drugs.
• Adverse drug reactions occurred in 0.77% of patients, including four serious adverse drug reactions in four patients (thrombocytopenia, hyponatremia, rhabdomyolysis, and rash).
• Regarding important potential risks, cardiovascular events, renal disorder, and decreased platelets were observed in one, one, and two patients, respectively.
• The cutaneous improvement rate (significantly improved or improved) was 95.5%, with significantly higher improvement rates in patients treated with amenamevir for 7 days and in patients with less severe cutaneous lesions or less pain.
• Factors affecting the time to pain resolution were the severity of cutaneous lesions and pain at the start of amenamevir treatment and older age.

"Our study showed Amenamevir to be a safe and effective treatment option for patients with herpes zoster, with a favourable safety profile and high cutaneous improvement rates," the researchers concluded.

Reference:

Imafuku, S., Korematsu, K., Mori, N., Kani, T., & Matsui, K. Real-world safety and efficacy of amenamevir in patients with herpes zoster in Japan: A postmarketing observational study (REWARD). The Journal of Dermatology. https://doi.org/10.1111/1346-8138.16876