Separately, the Institute for Clinical and Economic Review previously concluded that Aimovig’s use is cost-effective but only after patients try "existing preventive treatments, which are far less expensive."

Moreover, NICE also pointed out that the data "doesn’t fully reflect patients seen in clinical practice in the NHS," and that its long-term effectiveness for both the chronic and episodic migraine populations is as yet unknown.

Due to the "substantial uncertainty" in the evidence, NICE ruled that Aimovig is not a cost-effective use of NHS resources. But that doesn’t mean the end of the road for Aimovig with NICE. The agency often overturns its own decision after considering new data or a bigger discount.

"We will work with the company to ensure that they are given every opportunity to address the issues highlighted in these provisional recommendations," Meindert Boysen,  Pharm.D., director of the Centre for Health Technology Evaluation at NICE, said in a statement.

It’s still a blow for Aimovig as it tries to maximize a head-start advantage over Ajovy and Emgality. Though Novartis and U.S. co-marketer Amgen have expressed enthusiasm over the drug’s early uptake, they have yet to specify how many of the patients are actually getting billed instead of receiving it for free. Leerink analyst Geoffrey Porges has predicted that the total CGRP market will be $6.9 billion in 2025 and that Aimovig will lead the pack.

In Europe, Emgality has already won official European Commission approval, and NICE is expected to convene a meeting about its coverage June 20. Ajovy’s European nod could also come soon.