Treatment interruptions may result in poor T-cell recovery in patients with nadir CD+ count | HTB

Treatment interruptions may result in poor T-cell recovery in patients with nadir CD+ count <50 cells/mm3

Treatment interruptions have the potential to decrease the toxicity of highly active antiretroviral therapy (HAART) and improve the immune response to HIV, although the likelihood of the latter appears dubious in chronically-infected patients.

However, they also carry some risk since CD4+ counts can fall significantly in some patients and opportunistic infections and other adverse events can occur. Several studies presented at the 42nd ICAAC examined the safety of treatment interruptions.

One study by Maserati and colleagues evaluated treatment interruptions in 122 patients who had been on PI-containing HAART for more than six months, with a CD4+ count of at least 300 cells/mm3 and a viral load <50 copies/mL on therapy.

The enrolled patients were randomised to continue HAART or to undergo a series of treatment interruptions (TI), with an alternating one month on and one month off HAART for one year. If a patient in the TI arm had a CD4+ T cell count <200 cells/mm3 after an “on” month, he or she had to be dropped from the study.

Pursuant to the protocol five patients in the TI arm had to stop therapy due to a failure of their CD4+ count to recover to >200 cells/mm3 at the end of an on therapy month. All of these patients had a nadir CD4+ cell count <50 cells/mm3. Twelve patients in the TI arm who also had a nadir CD4+ count <50 did not have to stop the TI protocol, and none of the patients with a CD4+ nadir >50 had to do so.

The nadir CD4+ count of the three groups (TI discontinuations with nadir <50 cells/mm3, TI completers with CD4+ count nadir <50 cells/mm3, and TI completers with CD4+ count nadir >50 cells/mm3) revealed differences among the groups in median baseline CD4+ count at therapy discontinuation, 427, 473 and 607 cells/mm3, respectively, but the three groups had similar values regarding age, time on HAART, and duration of HIV-RNA suppression.

Relative to patients who never had a CD4+ count <50 cells/mm, patients with a CD4+ count nadir <50 cells/mm3 had a 17.9 fold increased risk of having to discontinue the TI due to a CD4+ count decrease to <200 cells/mm3 at the end of an on month.

The authors conclude: “The loss of CD4 cells below 200 cells/mm3 was associated with a nadir <50 cells/mm3 and in most cases it is associate to a poor CD4+ cell recovery after ‘off’’ periods.”

R Maserati and others. CD4+ Cell Loss During STIs (Structured Treatment Interruption). Abstract 1745. 42nd ICAAC

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