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A 1-Year Survey of Zoster-Associated Pain after Amenamevir Treatment
Makoto Kawashima1,2, Yoshiki Miyachi3,4,5
1NPO Health Institute Research of Skin, 2nd Floor, Fukuda Building 1-8-9 Kanda, Chiyoda-ku, Tokyo, 101-0047, Japan. makoto.kawashima0404@gmail.com.
Introduction:
Amenamevir is a new anti-varicella-zoster virus drug that inhibits the helicase-primase complex involved in viral replication. Amenamevir has the same effect as valaciclovir on acute pain and skin eruption, but no studies have examined the presence of long-term zoster-associated pain (ZAP) or postherpetic neuralgia (PHN) after amenamevir treatment.
Methods:
A total of 785 herpes zoster patients treated with amenamevir were followed up for 12 months. Patients recorded their pain status on a questionnaire once a month.
Results:
The proportion of patients with pain was 20.8% at 90 days, 8.0% at 180 days, 3.8% at 270 days, and 2.7% at 360 days after treatment. The median residual pain duration was 48 days. ZAP resolution rate slowed between 90 and 120 days, suggesting that the main feature of ZAP is a shift from nociceptive pain to neuropathic pain. Older age and more severe skin symptoms at the first visit were associated with a higher risk of developing PHN. Median ZAP duration was high for the head, face, and upper back and chest. Regarding the nature of pain, sudden pain attacks that felt like electric shocks, sensation of numbness, burning sensation, and cold/heat pain tended to remain as PHN.
Conclusions:
Although conclusions must remain tentative without further comparative studies, amenamevir seems to have a similar effect on PHN as conventional nucleoside analogs, despite having a different action mechanism.
Clinical Trial Registration:
UMIN000035938.
Insights
Amenamevir shows promise in treating herpes zoster, with long-term pain resolution rates improving over 12 months. This new antiviral drug appears comparable to traditional treatments for preventing postherpetic neuralgia (PHN).
Area of Science:
- Virology
- Pharmacology
- Pain Management
Background:
- Amenamevir is a novel antiviral targeting the varicella-zoster virus helicase-primase complex.
- Its efficacy in preventing long-term zoster-associated pain (ZAP) and postherpetic neuralgia (PHN) remains under-investigated compared to valaciclovir.
Purpose of the Study:
- To evaluate the incidence and duration of ZAP and PHN in patients treated with amenamevir.
- To identify risk factors associated with the development of PHN after amenamevir therapy.
Main Methods:
- A 12-month follow-up study of 785 herpes zoster patients treated with amenamevir.
- Monthly patient-reported pain status questionnaires were utilized.
Main Results:
- Pain prevalence decreased from 20.8% at 90 days to 2.7% at 360 days.
- The median residual pain duration was 48 days, with a notable shift from nociceptive to neuropathic pain between 90-120 days.
- Older age and severe initial skin symptoms were linked to higher PHN risk; specific pain types (electric shock, numbness, burning) persisted as PHN.
Conclusions:
- Amenamevir demonstrates a potential for managing PHN, similar to nucleoside analogs, despite a distinct mechanism of action.
- Further comparative studies are needed to solidify these findings, but amenamevir appears effective in reducing long-term pain after herpes zoster.
