Occipital Nerve Stimulation for Attack Prevention in Medically Intractable Chronic Cluster Headache: The Randomized, Double-Blind, Electrical Dose-Controlled ICON Study

Background: Occipital nerve stimulation (ONS) showed promising results in small uncontrolled trials in patients with medically intractable chronic cluster headache (MICCH). ONS causes paraesthesia preventing comparison versus placebo. Methods: After 12 weeks baseline observation, patients with CCH and prior failure to ≥3 standard preventive medications and ≥4 weekly attacks of CH were randomly allocated to 24 weeks double-blind 100% or 30% electrical dose ONS. These intensities were hypothesised to cause similar paraesthesia, mitigating unblinding, but differential efficacy. In weeks 25-48, participants received individually-optimised open-label ONS, which was then continued during regular patient care. Primary outcome was the weekly mean attack frequency (MAF) in weeks 21-24. Results: We enrolled 150 patients and randomized 130. At baseline, weekly MAFs were highly stable (p=0.38 for trend) but skewed (median 15.75; IQR 9.44, 24.75). In weeks 21-24, the median change from baseline across all participants was -5.2 (-11.18, -0.18; p<0.001) attacks per week, without difference between treatment arms (-2.42; 95%CI: -5.17, 3.33). The median overall relative MAF reduction was 42.56% (80.05%, 1.80%). Of all participants, 44.6% (95%CI: 36.3%, 53.2%) had ≥50% MAF reduction. Mean attack intensity (0-10) decreased from 7.58 (95%CI: 7.31, 7.85) to 5.57 (95%CI: 5.07, 6.06). Improvements were sustained throughout the entire study and a mean 5 year (range 1.5-8.5) follow up. There were no unexpected biological or hardware-related adverse events and 91% of participants would recommend ONS to other patients. Conclusions: ONS was associated with major reduction in attack frequency and intensity in patients with MICCH, without difference between 100% and 30% stimulation intensity. The intervention was well-tolerated and associated with high patients satisfaction. Large placebo responses seem unlikely, given the considerable and longterm sustained clinical improvement in patients with such a long and unremitting history of highly disabling MICCH and a stable 12 week pretreatment observation. Trial Registration: Clinical trials.gov NCT01151631 Funding Statement: The Spinoza 2009 Lifetime Scientific Research Achievement Premium from the Netherlands Organization for Scientific Research, the Dutch Ministry of Health (as part of a national provisional reimbursement program for promising new treatments), the NutsOhra Foundation from the Dutch Health Insurance Companies, and an unrestricted grant from Medtronic, all to MDF. Declaration of Interests: MDF reports grants and consultancy or industry support from Electrocore, Medtronic, Eli Lilly, Amgen, Novartis, and TEVA, and independent support from The Netherlands Organization for Scientific Research (NWO), The Netherlands Organization for Health Research and Development (ZonMW), The Dutch Brain and Heart Foundations, The Dutch Ministry of Health, and The NutsOhra Foundation from the Dutch Insurance Companies. FH reports grants and consultancy fees from ABBOTT, Saluda and Pfizer and independent support from The Netherlands Organization for Health Research and Development (ZonMW). JH reports consultancy fees from Eli Lilly and Novartis IF reports travel grants from Electrocore WMM reports consultancy fees from Eli Lilly JW reports grants and consultancy fees from ABBOTT, Saluda and Boston and independent support from The Netherlands Organization for Health Research and Development (ZonMW). FW reports grants and consultancy fees from Abbott, Medtronic, Nevro and Saluda DM reports grants and consultancy and speaker fees from Novartis NV, consultancy fees from Eli-Lilly Benelux, travel grants from electroCore LLCAbbott, Medtronic, Nevro and Allergan, speaker fees from Neurolite, Saluda LE reports consultancy fees from Medtronic and ABBOT JWK reports grants and consultancy fees from ABBOTT, Saluda and Boston, and independent support from The Netherlands Organization for Health Research and Development (ZonMW). EGMC reports grants and consultancy or industry support from Lilly, Novartis, ATI and TEVA, and independent support from the Innovatiefonds Zorgverzekeraars. The other authors report no disclosures. Ethics Approval Statement: Local ethic committees at each participating center approved the study protocol.