Actos opened up to first generic competition in Japan
This article was originally published in Scrip
330 products from 63 manufacturers have been awarded reimbursement prices in the latest listing of generic drugs in Japan, which marks the advent of the first such competition for Takeda's big-selling oral antidiabetic Actos (pioglitazone).
The listing, one of two a year for generics, was delayed from May by the after-effects of the 11 March earthquake and tsunami.
Original products containing three other active ingredients also saw their first generic entrants - edaravone (Mitsubishi Tanabe Pharma's (MTP) Radicut), risedronate sodium (Takeda/Eisai's Benet/Actonel; licensed from Ajinomoto), and ribavirin (MSD's Rebetol).
Sales erosion following the loss of exclusivity in Japan is usually much less dramatic than in other major markets such as the US however, for a variety of reasons including prescriber brand loyalty and concerns over the stable supply and quality of generics.
Overall, generics currently account for a modest 7% by value and 23% by volume of the country's roughly $110 billion prescription market.
With Japanese sales of ¥47.9 billion ($588 million) in the fiscal year to 31 March, it was not surprising that Actos attracted the highest number of generic entrants, with 50 products from 18 firms being listed. Most of these were standard (rather than oral-dissolving) 15mg and 30mg tablet formulations.
But given the ongoing international regulatory concerns and reviews over pioglitazone's relationship to bladder cancer, it looks likely that any effect on sales this year will take down generic products as well.
Manufacturers given a national health insurance tariff price for the product on 24 June included a number of leading domestic generics firms such as Sawai and Nichi-Iko and the generics arms of innovator companies including Sandoz (Novartis), Daiichi Sankyo Espha and Mochida.
Takeda recently took legal action claiming patent infringement against 18 firms which have received approvals for their versions of Actos, through which it is seeking injunctions against manufacture and sale. Several use patents relating to the combination use of the original thiazolidinedione molecule remain in force in Japan (scripintelligence.com, 16 June 2011).
As usual, the initial reimbursement prices of the Actos and other generics in the listing were set at 70% of the current price of the original product. Two active ingredients saw more than 20 generics listed, triggering a rule whereby the price of the new entrants was set at 90% of that of the cheapest currently available generic.
The ministry of health, labour and welfare noted that edaravone attracted 35 generic versions from 22 companies. The molecule is a free radical scavenger used as a cerebral neuroprotectant to aid recovery following cerebral infarction, and sales of the original were ¥28.7 billion last fiscal year, making it MTP's number two product.
Among those having their generic versions listed was Pfizer, which has just launched its established products business in Japan and also plans to start marketing a generic version of the injectable carbapenem antibiotic meropenem on 1 July.