More Effective and Affordable Hepatitis Therapies Needed in Asia

China, Taiwan and South Korea represent endemic areas for viral hepatitis, with prevalence rates ranging from 4-13 percent for Hepatitis B (HBV) and from 1-4 percent for Hepatitis C (HCV).

While there are several therapeutic options available for the treatment of HBV, sustained responses remain difficult to achieve. Concerning HCV, treatment choices are limited, and efficacy rates are low particularly in patients infected with genotype 1, the most common subtype in these countries. Datamonitor’s physician survey found that although doctors place a high emphasis on efficacy, affordability often determines the choice of treatment.

“Cost constraints are limiting the use of more potent and effective therapies in those regions. For instance, non-pegylated interferons are still being commonly used by patients with more limited resources,” explains Mansi Shah, senior analyst at Datamonitor.

The Asia Pacific region is among the world’s worst affected areas with an estimated 5-20 percent of the population being positive for HBV surface antigen (HBsAg). The epidemiology of HCV infection in different parts of Asia is similarly varied, with an average seroprevalence of HCV antibodies (anti-HCV) of less than 2.5 percent in healthy adults.

According to IMS Health, viral hepatitis drug sales in China, Taiwan and South Korea totaled US$562 million in 2008. Revenues of this therapeutic class, consisting of small molecule antivirals and interferon alpha, are dominated by the former, illustrating the higher disease burden of HBV compared with HCV in Asia.

There are currently several therapeutic options available for HBV, including two formulations of interferon alpha (standard and pegylated) and six nucleos(t)ide analogues (lamivudine, adefovir, entecavir, telbivudine, tenofovir and clevudine). Interferon-based therapy is more likely to achieve a sustained virological response, but is less convenient and less well tolerated.

Treatment-maintained response can also be achieved with long-term nucleos(t)ide analogue therapy in the majority of patients; however, these agents are prone to the development of resistance over time. Datamonitor’s research indicates that for first line regimens, monotherapy with Zeffix (lamivudine) or Baraclude (entecavir) is generally preferred across China, Taiwan and South Korea.

Primarily in China, but also in Taiwan, there is some use of Traditional Chinese Medicine (TCM) in conjunction with pharmacological therapy. Indeed, 10 percent of patients in China and Taiwan, and 2 percent in South Korea receive TCM alone as their initial regimen. For second line regimens, combination therapy is frequently used across Asian markets. The combination of Zeffix and Hepsera (adefovir) is the most popular choice, as it retains efficacy against resistant strains.

For patients with chronic HCV, pegylated interferon alpha plus ribavirin is the current mainstay of treatment. While both international and Asia-specific guidelines recommend both PegIntron and Pegasys. Pegasys appears to be the preferred brand across the Asian markets. Treatment regimens across the East Asian countries, notably China, are more fragmented in comparison: non-pegylated interferons and TCM are used more than elsewhere.

“Given the limited number of drugs available for treatment of HCV, physicians often have to retreat patients with the same regimen (pegylated interferon plus ribavirin) and maybe extend the duration of therapy. In the Asian countries, TCM also gains popularity in this setting, both to boost efficacy and to improve tolerability,” adds Shah.

Another area that plays an important role in prescription choice is the cost. According to Datamonitor’s survey, approximately 4-6 percent of HBV infected patients and 3-10 percent of HCV infected patients do not receive therapy due to affordability issues. For HBV, the inexpensive lamivudine still remains the preferred antiviral agent in first line therapy, and for HCV, non-pegylated interferons are still being commonly used by patients with limited resources.

“The predominance of HCV genotype 1 across Asia represents an attractive commercial opportunity for companies developing novel HCV therapies targeting this patient group. However, pricing strategies for novel drugs must be carefully adjusted to local conditions in order to gain traction in emerging markets both for Hepatitis B and C” concludes Shah.