Counterfeit hep C drug Harvoni found in Japan

Japan's government has said counterfeits of Gilead Sciences' big-selling hepatitis C virus therapy Harvoni have been discovered at a pharmacy chain in Nara Prefecture.

The discovery is not surprising, given that Harvoni (sofosbuvir/ledipasvir) carries a hefty price tag and is one of the top-selling drugs in the world – and is tough for patients to access in some markets. Nevertheless, the discovery of the counterfeits in a retail pharmacy in a well-regulated pharma market such as Japan rings warning bells.

It is also not the first time that fake Harvoni has been discovered. Last year, Switzerland's medicines regulator Swissmedic raised the alarm after coming across samples of a knock-off product in circulation in Israel that it said may have originated from a company in India.

The Ministry of Health, Labor and Welfare (MHLW) said in a statement that the counterfeits came from "unofficial sources" and that it is currently investigating how they were able to penetrate the supply chain. Meanwhile, Gilead has indicated it was working with the authorities to try to establish the source, and has sent letters to patients, pharmacies and doctors providing guidance on how to spot the fakes.

In particular, the company notes that while the counterfeits generally roughly the same shape and carry the same markings as genuine tablets (see image), they can sometimes be more oval than diamond/rhomboid and colours vary from light yellow to purple. Unlike some knock-offs the genuine product also has an aluminium seal on the bottle mouth that peels off easily, and will have exactly 28 tablets inside.

Gilead sales hit a peak of $14bn in 2015 but have started to slip back, in part due to competition and discounting in markets such as the US, but also because the pool of eligible patients is getting smaller.

The product's high price in some markets means that patients sometimes try to source the drug from cheaper suppliers overseas, raising the risk they may be sold a counterfeit. Harvoni has a list price of around $95,000 a year in the US although recent studies suggest discounting may cut that almost in half.

Gilead has access deals in low-income countries that have cut the cost of therapy to just $1 per pill, but even at these prices the drug is out of reach of some patients. Meanwhile, patients in middle- and high-income countries can struggle to get reimbursement for the therapy.