Sanofi and Regeneron’s closely-watched cholesterol buster Praluent (alirocumab) has cleared a key hurdle on the path to market after its approval was backed by US Food and Drug Administration advisors.

The FDA’s Endocrinologic and Metabolic Drugs Advisory Committee has voted 13-3 in favour of green-lighting the drug, which is neck and neck with Amgen’s rival PCSK9 inhibitor Repatha (evolocumab) in the race to be the first in the class to break onto the US market.

This new class of medicines is expected to generate billions of dollars, but the potential of Praluent could be muted in the first instance as there is talk of limiting its use to patients at very high risk of elevated cholesterol because of familial hypercholesterolaemia.

Also, a small shadow of doubt has been cast over whether evidence of cardiovascular benefit is strong enough for widespread use; a Regeneron/Sanofi study testing for CV outcomes is already underway, but results won’t be available until 2017.

Amgen’s Repatha is up for discussion later today, but in documents posted ahead of the panel meeting reviewers seem to have taken an overall positive stance on the drug. Both rivals are widely expected to win FDA approval in the summer. Nevertheless, a huge question mark remains over their affordability. 

While prices of the drugs have not yet been disclosed, US pharmacy benefit manager Prime Therapeutics says initial estimates indicate their tags could fall between $7,000 and $12,000 per year, which “could quickly cost the US health system up to $23.3 billion a year”, it warns.