Real-world effectiveness of onabotulinumtoxinA treatment for the prevention of headaches in adults with chronic migraine in Australia: a retrospective study

Abstract

Background: OnabotulinumtoxinA (BOTOX®, Allergan plc, Dublin, Ireland) is approved for the preventive treatment of headaches in adult patients with chronic migraine (CM) in Australia by the country's reimbursement mechanism for medicines, the Pharmaceutical Benefits Scheme (PBS). To our knowledge, this study represents the first focused report evaluating real-world evidence of onabotulinumtoxinA treatment via the PBS in Australian clinics.

Methods: This study reviewed the medical records of adults with inadequately controlled CM from 7 private neurology practices in Australia who, beginning in March 2014, received PBS-subsidized onabotulinumtoxinA per product labelling for the first time. The primary effectiveness measure was the percentage of patients achieving a response defined by 50% or greater reduction in headache days from baseline after 2 treatment cycles. Additional data were recorded in the case report form when available and included demographics, clinical characteristics, headache severity and frequency, Headache Impact Test (HIT-6) score, medication use, and days missed of work or study at baseline, after 2 treatment cycles, and at last follow-up. Differences in mean changes from baseline were evaluated with a 1-tailed t-test or Pearson's chi-squared test (p < 0.05).

Results: The study population included 211 patients with a mean (SD) of 25.2 (5.3) monthly headache days at baseline. In the primary outcome analysis, 74% of patients achieved a response, with a mean (SD) of 10.6 (7.9) headache days after 2 treatment cycles (p < 0.001). Secondary effectiveness outcomes included mean (SD) reductions in HIT-6 score of - 11.7 (9.8) and - 11.8 (12.2) after 2 treatment cycles (p < 0.001) and final follow-up (p < 0.001), respectively, and mean (SD) decreases in days per month of acute pain medication use of - 11.5 (7.6) after 2 treatment cycles (p < 0.001) and - 12.7 (8.1) at final follow-up (p < 0.001).

Conclusion: This study provides additional clinical evidence for the consistent effectiveness of onabotulinumtoxinA for the treatment of CM in Australia. This effectiveness was made evident by reductions in migraine days, severe headache days, and HIT-6 scores from baseline.

Keywords: Australia; Chronic migraine; Codeine; Headache; Migraine disorders; OnabotulinumtoxinA; Retrospective studies.

Conflict of interest statement

CS has received a previous travel grant from Allergan and has received advisory board and/or lecture fees from Allergan, Novartis, and SciGen. RSta has received advisory board and/or lecture fees from Allergan, Biogen, Eli Lilly, Novartis, SciGen, and Teva. NL has received partial funding for a clinical nurse and a travel grant from Allergan, advisory board fees from Novartis, and a clinical trial grant from Teva. JR has received travel grants and nurse funding from Allergan and advisory board fees from Allergan, Novartis, and Teva. DC and RSch have nothing to disclose. RJ is an employee of Allergan.

Figures

Fig. 1

Proportion of patients achieving ≥50% reduction from baseline in monthly headache days after 2 treatment cycles. PBS, Pharmacy Benefits Scheme

Fig. 2

Frequency of headache, migraine, and severe headache days. The n’s represent patients with available data at each time point. P-values indicate significant decrease from baseline, one-sided t-test

Fig. 3

HIT-6 scores. HIT-6, 6-item Headache Impact Test. P-values indicate significant decrease from baseline, one-sided t-test

Fig. 4

Work or study days missed due to migraine. P-values indicate significant decrease from baseline, one-sided t-test

Fig. 5

Days of acute pain medication use. P-values indicate significant decrease from baseline, one-sided t-test

Fig. 6

Acute pain medication usage by type. OTC, over the counter. *P < 0.050, Pearson’s Chi-squared test