METHODS: 152 H. contortus individual adult worms were collected from seven different geographical regions in China. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined.

RESULTS: Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries, including Australia, Brazil, Germany, Italy, Malaysia, Sweden, the USA and Yemen. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Chinese populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries.

METHODS: DRAGON study was conducted across 9 Asian countries or regions including mainland China, India, the Republic of Korea, Malaysia, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. Patients (N = 557) with CM (aged 18-65 years) were randomised (1:1) to receive once-monthly subcutaneous erenumab 70 mg or matching placebo for 12 weeks. The primary endpoint was the change in monthly migraine days (MMD) from baseline to the last 4 weeks of the 12-week double-blind treatment phase (DBTP). Secondary endpoints included achievement of ≥ 50% reduction in MMD, change in monthly acute headache medication days, modified migraine disability assessment (mMIDAS), and safety. Study was powered for the primary endpoint of change from baseline in MMD.

RESULTS: At baseline, the mean (SD) age was 41.7 (± 10.9) years, and 81.5% (n = 454) patients were women. The mean migraine duration was 18.0 (± 11.6) years, and the mean MMD was 19.2 (± 5.4). 97.8% (n = 545) randomised patients completed the DBTP. Overall, demographics and baseline characteristics were balanced between the erenumab and placebo groups except for a slightly higher proportion of women in the placebo group. At Week 12, the adjusted mean change from baseline in MMD was - 8.2 days for erenumab and - 6.6 days for placebo, with a statistically significant difference for erenumab versus placebo (adjusted mean difference vs placebo: - 1.57 [95%CI: - 2.83, - 0.30]; P = 0.015). A greater proportion of patients treated with erenumab achieved ≥ 50% reduction in MMD versus placebo (47.0% vs 36.7%, P = 0.014). At Week 12, greater reductions in monthly acute headache medication days (- 5.34 vs - 4.66) and mMIDAS scores (- 14.67 vs - 12.93) were observed in patients treated with erenumab versus placebo. Safety and tolerability profile of erenumab was comparable to placebo, except the incidence of constipation (8.6% for erenumab vs 3.2% for placebo).

CONCLUSION: DRAGON study demonstrated the efficacy and safety of erenumab 70 mg in patients with CM from Asia. No new safety signals were observed during the DBTP compared with the previous trials.