Objectives: To compare gastrointestinal (GI) tolerability and patient preference for the new 625 mg formulation of nelfinavir (NFV) and the marketed 250 mg tablets (Viracept) in HIV-1-infected patients.
Methods: Virologically controlled patients (n=126) treated with a nelfinavir (NFV) 250 mg-containing regimen for > or =8 weeks completed a stool diary for 14 days to assess baseline bowel function. After switching to the NFV 625 mg formulation [1250 mg twice a day (bid)] for 28 days, patients continued their stool diaries and at study completion answered a questionnaire regarding formulation preferences.
Results: The incidence and mean weekly duration of GI upset over a 2-week period were lower with NFV 625 mg than with NFV 250 mg (79.8% vs. 84.9% of patients and 2.1 vs. 3.0 days, respectively). Fewer patients experienced moderate or severe diarrhoea with NFV 625 mg (6.5% vs. 11.1%), and the incidence of investigator-assessed diarrhoea also decreased with NFV 625 mg. Importantly, there was a significant improvement overall in the incidence of diarrhoea (any grade) when patients switched to NFV 625 mg [38 of 124 (31%) improving, 69 of 124 (56%) stable and 17 of 124 (14%) worsening on NFV 625 mg; P<0.01]. At study completion, most patients expressed a preference to continue treatment with NFV 625 mg [112 of 122 (91.8%); P<0.0001], with only one patient (0.8%) preferring to resume treatment with NFV 250 mg. The new formulation was well tolerated with no new safety concerns.
Conclusions: The new NFV 625 mg formulation is better tolerated and preferred by patients switching from NFV 250 mg tablets. By reducing the daily pill count and improving GI tolerability, the NFV 625 mg formulation may enhance patient adherence to NFV-containing antiretroviral regimens and thus potentially improve virological outcomes.