Counterfeits of Gilead’s mega-blockbuster hepatitis C treatment Harvoni, which is generating billions per quarter in sales for the company, are emerging in Israel.

Switzerland’s drug regulator Swissmedic said over the weekend that the plastic bottles of the counterfeits, which originated in India, were imported via a Swiss trading company and “contain white instead of genuine yellow film-coated tablets,” the regulator said.

Swissmedic is working with other EU authorities to establish whether Harvoni packs with counterfeit contents have also been imported into other countries.

The counterfeit versions of the hepatitis C treatment, which have a list price in the US of $94,500 for a 12-week regimen, come as Swissmedic acknowledges that many Swiss patients are purchasing Harvoni abroad because of the price is dramatically lower in other countries like India and Egypt.

The discovery of counterfeit Harvoni comes as hepatitis C patients in the US and EU are increasingly coming up with unique ways to obtain Gilead’s drugs, which are sold for a fraction of the US list price in other countries. In October, Gilead reported Q3 sales of $4.8 billion for its two hepatitis C drugs.

Swissmedic advises against purchasing any medicine from unknown sources, and particularly against ordering them via the Internet.

“There is no guarantee that medicines sold at very low prices from countries with no comparable medicines control system actually contain the declared active ingredient or the correct dosage of that active ingredient,” Swissmedic said.

The Drug Regulatory Authority of Pakistan (DRAP) also has uncovered illegal manufacturing of Gilead’s other hepatitis C product Sovaldi (sofosbuvir).

Gilead in 2014 licensed 11 generic Indian drugmakers, including Hetero Labs, Cipla and Aurobindo Pharma, to make and sell generic versions of Sovaldi in almost 100 developing countries, and Mylan has already launched its generic version. The company has also said it would launch its own branded version of Sovaldi in India at a price of $300 per month.

Swissmedic Announcement