This multicenter, randomized, open-label, parallel-group study (ADMIT-NeP) investigated the effectiveness, safety, and tolerability of combining Mirogabalin with standard pain management (such as nonsteroidal anti-inflammatory drugs [NSAIDs] and/or Acetaminophen) for alleviating peripheral neuropathic pain post-thoracic surgery.

Patients diagnosed with peripheral neuropathic pain were randomly allocated in a 1:1 ratio to receive either Mirogabalin in addition to conventional therapy or conventional treatment alone. Out of 131 consenting volunteers, 128 were randomly allocated (63 in the Mirogabalin add-on arm and 65 in the conventional treatment arm). Alteration in pain from baseline to week 8, estimated by visual analogue scale (VAS) at rest was the key outcome.                       

The least square mean change (with 95% confidence interval [CI]) in VAS scores for pain at rest from baseline to week 8 in the study groups is shown in Table 1. The inter-group difference was not clinically meaningful (-3.6 [95% CI: -8.7, 1.5], P = 0.161).

However, a post-hoc assessment revealed that among volunteers with a Self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) score ≥ 12 at baseline, there was a notable drop in VAS score correlating with higher S-LANSS scores in the Mirogabalin add-on arm, whereas no such correlation was witnessed in the conventional treatment group (interaction P value = 0.014). Chronic pain was reported in 7.9% vs. 16.9% of subjects (P = 0.171) at week 12 in the Mirogabalin add-on vs. conventional therapy groups, respectively.

Based on the alterations in the Pain Disability Assessment Scale and the EQ-5D-5L index value from baseline to week 8, improvements in activities of daily living and quality of life were profound in the Mirogabalin add-on group compared to the conventional treatment group (P < 0.001). Concomitant usage of Mirogabalin and conventional pain relief treatment was well-tolerated. Dizziness (12.7%), urticaria (3.2%), and somnolence (7.9%) were the most commonly encountered adverse events in the Mirogabalin add-on group, with most adverse events being mild or moderate in severity.

While the addition of Mirogabalin to conventional therapy did not lead to a considerable betterment in pain as measured by VAS scores, it did elicit notable enhancements in activities of daily living and quality of life for those battling peripheral neuropathic pain following thoracic surgery.