Mirogabalin Effective for Treating Central Neuropathic Pain After SCI

Mirogabalin effectively improves average daily pain score (ADPS) in patients with central neuropathic pain due to spinal cord injury (SCI), according to study findings published in the journal Neurology.

Researchers conducted the phase 3, multinational, randomized, double-blind, placebo-controlled trial (ClinicalTrials.gov identifier: NCT03901352) at 120 sites throughout Japan, Korea, and Taiwan, with participants recruited either as inpatients or as outpatients. Although it is well known that mirogabalin is effective for the treatment of peripheral neuropathic pain, evidence for use of the agent in patients with central neuropathic pain is lacking. The researchers sought to explore the efficacy and safety of mirogabalin for the treatment of central neuropathic pain in patients who had experienced a traumatic SCI.

Study participants were randomly assigned in a 1:1 ratio to receive mirogabalin 5 mg twice daily for 1 week, mirogabalin 10 mg twice daily for 1 week, mirogabalin 10 mg or 15 mg twice daily for 12 weeks, or placebo. Patients with moderate renal impairment were treated with half the dosage. The primary efficacy endpoint of the study was change from baseline in the weekly ADPS at week 14. Secondary endpoints were ADPS responder rates, Short-Form McGill Pain Questionnaire (SF-MPQ), average daily sleep interference score (ADSIS), and Neuropathic Pain Symptom Inventory (NPSI).

All patients were enrolled beginning March 14, 2019; follow-up was completed on September 9, 2020. Among 443 individuals evaluated for eligibility, 300 were randomly assigned to treatment — 150 each to the mirogabalin and the placebo groups. The modified intention-to-treat-populationincluded all 150 individuals in the mirogabalin group and 149 individuals in the placebo group. Overall, 133 patients in the mirogabalin arm and 136 patients in the placebo group completed the study. The most common reasons for withdrawal from the study were patient decision and adverse events (AEs).

The researchers found that treatment with mirogabalin was associated with a statistically significant, clinically relevant improvement in change from baseline in the weekly ADPS at week 14 (least-squares mean difference [LSMD] vs placebo, –0.71;
95% CI, –1.08 to –0.34; P =.0001).

At week 14, responder rates were higher with mirogabalin compared with placebo (odds ratio [OR], 1.91; 95% CI, 1.11-3.27 for the ≥30% responder rate and OR, 2.52; 95% CI, 1.11-5.71 for the ≥50% responder rate).

Statistical improvements were also observed in SF-MPQ (LSMD, –2.4; 95% CI, –3.8 to
–1.1), ADSIS (LSMD, –0.71; 95% CI, –1.04 to –0.38), and NPSI (LSMD, –7.7; 95% CI, –11.1 to –4.4) scores. Most of the treatment-related AEs reported were mild, and no serious adverse drug reactions were observed.

Several limitations of the study warrant mention. Since the study was conducted exclusively in Asia, generalizability of the results to other racial/ethnic populations is limited. Further, the short duration of the study prevents any conclusions about long-term efficacy and safety of mirogabalin in this patient population. Additionally, use of placebo rather than an active comparator limits any direct comparison of safety/efficacy with existing treatments.

Overall, the findings suggest mirogabalin is a promising treatment for patients with central neuropathic pain due to SCI.

The researchers concluded that “Although the present results were obtained only in patients with CNeP [central neuropathic pain] due to SCI, mirogabalin shows promise for CNeP with other etiologies; future studies should investigate this potential indication.”

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.