Long-term efficacy and safety of fosamprenavir plus ritonavir versus lopinavir/ritonavir in combination with abacavir/lamivudine over 144 weeks.

Purpose: The KLEAN study extension assessed the long-term efficacy and safety of fosamprenavir-ritonavir (FPV/r) and lopinavir-ritonavir (LPV/r), both administered with abacavir/lamivudine (ABC/3TC) fixed dose combination, over 144 weeks. Methods: KLEAN was an open-label, noninferiority study that randomised anti retroviral-naive patients to FPV/r twice daily (bid) or LPV/r bid with ABC/3TC once daily (qd). Patients with a viral load of < 400 copies/mL at Week 48 were eligible to participate in the KLEAN study extension (up to 144 weeks) and continued with their previously randomised therapy. Results: The KLEAN study extension (48 to 144 weeks) randomized 199 patients. The proportion of TLOVR responders (HIV-1 RNA < 50 copies/mL) at Week 144 was 73% and 60% in the FPV/r and LPV/r arms, respectively. The proportion of TLOVR responders (< 50 copies/mL) was the same irrespective of baseline HIV-1 RNA (> 100,000 or <= 100,000 copies/mL). The Week 144 median (interquartile range) change from baseline CD4+ cell count was 300 (236-433) cells/mm(3) and 335 (225-444) cells/mm(3) in the FPV/r and LPV/r arms, respectively. Diarrhea was the most frequently reported adverse event. A small proportion of patients (FPV/r, 13%; LPV/r, 9%) discontinued study medication due to adverse events. Three patients (FPV/r, 1; LPV/r, 2) experienced virological failure between Week 48 and Week 144. Conclusion: The findings of the KLEAN study extension (48 to 144 weeks) support durable viral suppression with both FPV/r and LPV/r treatment regimens when used in combination with ABC/3TC irrespective of viral load at baseline. Both regimens were well tolerated and had similar safety profiles.