Safety analysis of Lexiva tablets 700 (fosamprenavir calcium hydrate) in post-marketing surveillance in Japan.

Objective

Fosamprenavir, a protease inhibitor (PI) to treat human immunodeficiency virus (HIV)-infected patients, has been approved in more than 40 countries and mainly used with nucleoside reverse transcriptase inhibitors. In Japan, Lexiva tablet (fosamprenavir calcium hydrate) has been marketed since January 2005 and used in clinical practice. The safety and effectiveness of fosamprenavir in HIV-infected Japanese patients were evaluated in an observational surveillance study (OTH112334).

Methods

A post-marketing surveillance study (PMS) of fosamprenavir usage in HIV-infected Japanese subjects evaluating drug safety was conducted under Good Post-marketing Study Practice from January 2005 to December 2014.

Results

Of 364 patients receiving fosamprenavir, 51% received emtricitabine/tenofovir disoproxil fumarate. Adverse events whose causal relationship could not be completely ruled out (adverse drug reactions; ADRs) were reported in 43.7%; the most common were diarrhoea (10.4%), hyperlipidaemia (8.5%) and hypertriglyceridaemia (6.9%). Serious ADRs were reported in 26 patients (32 events), including 1 death attributed to hepatic failure. Most ADRs occurred within 180 days after fosamprenavir was started. ADRs were more frequent in patients with the Centers for Disease Control and Prevention category B (AIDS or lipid disorders) or in those taking fosamprenavir combined with abacavir and lamivudine. Although spontaneous bleeding has been reported in hemophiliac patients taking other PIs, in this survey, only one muscle haemorrhage case was reported in 24 hemophiliac patients.

Conclusions

The results of this PMS analysis in Japan support its known safety profile and identified no new safety risks for people living with HIV/AIDS in Japan currently on, or beginning treatment with, fosamprenavir.