Background: Zidovudine, the first antiretroviral agent, has short-term haematological toxicity. However, it is unclear whether patients tolerating long-term zidovudine-containing regimens will benefit from a switch to non-zidovudine-containing regimens.
Methods: One hundred and fifty-eight patients enrolled in the ALIZE trial receiving zidovudine at baseline were analysed. These patients were randomized to continue their regimen or to switch to a combination of emtricitabine, didanosine and efavirenz for 48 weeks. Changes from baseline in haemoglobin (Hb), neutrophil and platelet counts were compared between arms as well as the occurrence of cardiovascular events, bacterial infections, use of haematopoietic growth factors, blood transfusion and quality of life using the Medical Outcome Study HIV (MOS-HIV) health survey.
Results: Eighty-one patients continued their regimen and 77 switched. At 48 weeks, mean change from baseline in Hb were +0.73 and -0.37 g/dL in the switch and maintenance groups, respectively (P < 0.01). Mean neutrophil counts increased by 592 and 51 cells/mm(3) in the switch and maintenance groups, respectively (P = 0.02). The occurrence of cardiovascular events or bacterial infections was similar in both treatment arms with no use of haematopoietic growth factors or blood transfusion. Also, mean change from baseline in MOS-HIV physical and mental health summary scores was similar in both arms.
Conclusions: A switch from a long-standing zidovudine- to a non-zidovudine-containing regimen modestly improves haematological parameters and is not associated with obvious clinical benefit.