Boehringer Ingelheim’s second-generation hepatitis C virus protease inhibitor faldaprevir achieved a viral cure rate of nearly 90 per cent in Asian patients with the hard-to-treat genotype-1 form of the virus when combined with pegylated interferon and ribavirin.
A sub-analysis of Boehringer’s STARTVerso 1 and 2 trials – looking at patients from Japan, Korea and Taiwan who had not been tested previously for hepatitis C – also found that the combination reduced the duration of therapy needed to achieve reach this high sustained viral response, with 88 per cent of patients achieving a viral cure within 12 weeks, rising to 95 per cent after 24 weeks.
All told, the viral cure rate was 100 per cent for patients in Taiwan, 86 per cent in Korea and 85 per cent in Japan, according to Professor Masao Omata of Yamanashi Central and Kita Hospitals in Japan, who presented the data at a medical meeting in Singapore.
“There is a large population of treatment-naïve patients in this region in need of more effective treatment options,” he said, adding: “the results are particularly relevant given that hepatitis C virus presents a huge health burden in Asia.”
Faldaprevir is due to be filed for approval later this year based on data from four phase III trials in the STARTVerso programme, and is one of a new generation of hepatitis C virus protease inhibitors expected to break into the market currently dominated by Merck & Co’s Victrelis (boceprevir) and Vertex/Johnson & Johnson’s Incivo (telaprevir).
Other drugs emerging in the protease inhibitor class include Medivir/J&J’s simeprevir, Merck’s vaniprevir (MK-7009), Bristol-Myers Squibb’s asunaprevir and AbbVie’s ABT 450, which also boast superior viral cure rates and milder side effects than their first-generation cousins.
As a result, sales of Incivek and Victrelis are expected to decline as the new protease inhibitors and other new hepatitis C virus drug classes such as the NS5B nucleotide polymerase inhibitors come to market.
In fact, Incivek has already started to slump after it was linked to progressive and potentially fatal skin reactions which led to a boxed warning being added to its label in December 2012.
Victrelis has picked up the slack in the meantime, with sales reaching more than $500m last year up from $140m in 2011, but has disadvantages compared to newer drugs including a tendency to cause interactions with certain IV drugs for HIV.
That is significant because some patients with hepatitis C virus also have HIV, and as a result Boehringer has included co-infected patients in its faldaprevir trials programme.
Meanwhile, combinations of the newer agents are tipped to eventually replace injectable interferon-based therapy, as this is associated with serious side effects and is unsuitable for use in around half of all hepatitis C cases.
Boehringer recently started pivotal trials of an interferon-free combination regimen for hepatitis C virus based on faldaprevir, polymerase inhibitor BI 207127 and ribavirin.