Gilead Sciences has signed an exclusive deal with CVS Health Corp. to cover its hepatitis C drugs Sovaldi and Harvoni, a move that follows rival AbbVie’s exclusive deal late last month with pharmacy benefit giant Express Scripts to cover its hep C combination therapy.

The pharmacy benefit division of CVS said that it would cover AbbVie's Viekira Pak (ombitasvir, paritaprevir and ritonavir with dasabuvir) only under exceptional circumstances.

Viekira Pak costs roughly $83,000 for a course of treatment. Gilead's Sovaldi (sofosbuvir) and Harvoni (sofosbuvir and ledipasvir) cost roughly $84,000 and $94,000 respectively.

ISI Group analyst Mark Schoenebaum estimates that both pharmaceutical payers cover roughly the same number of patients. — Lena Freund