Patients who start anti-HIV therapy with a relatively intact immune system may be able to safely interrupt HAART for prolonged periods, according to Italian data presented to the 43rd ICAAC in Chicago on September 14th.
These findings could have significant implications for not only the future design of structured treatment breaks, but also influence decisions on when to start anti-HIV treatment.
Investigators recruited 114 patients to their study, all of whom had an HIV viral load below 50 copies/mL and a CD4 cell count above 800 cells/mm3. Patients were randomised on a two-to-one basis either to stop their therapy or continue with ongoing treatment. For patients in the treatment interruption arm, the aim was to maintain a CD4 cell count above 400 cells/mm3 and the primary endpoint was the number of patients remaining in the interruption arm at 18 months.
There were no significant baseline differences between patients in the interruption and ongoing treatment arms. Eight patients were lost to follow-up in the treatment arm, and one patient in the interruption arm withdrew from the study due to side-effects.
Treatment was recommenced by 21% of patients (one patient twice), because of a drop in their CD4 cell count to below 400 cells3. On average, patients spent 12.1% of the study period on treatment.
The only factor predictive of CD4 cell loss during treatment interruption was the lowest ever CD4 cell count prior to the initiation of HAART (p3. For patients who had a CD4 nadir of between 200 – 350 cells/mm3 the mean period of the first treatment interruption was significantly longer, at 14.1 months. The individuals who had a CD4 nadir of between 351 and 500 cells/mm3 had the most lengthy first treatment interruption, a mean of 17.8 months. Furthermore, those patients whose lowest ever CD4 cell count was above 500 cells/mm3 did not need to resume therapy at all within the follow-up period.
Regardless of nadir CD4 cell count, all the individuals resuming therapy experienced a rapid increase in their CD4 cell counts when treatment was resumed.
When a patient could safely interrupt therapy a saving of 300 euro per month was made in treatment costs, note the investigators, meaning that almost 500,000 euros were saved from the drugs budget of the investigator's treatment centre during the duration of the study.
On the basis of these data, the investigators conclude that anti-HIV therapy can be safely interrupted for a sustained period by patients who started HAART with a CD4 cell count of at least 350 cells3. Those patients who started HAART with lower CD4 cell counts experienced a more rapid decrease in CD4 cell count. These findings could shape decisions about when treatment-naïve individuals should start anti-HIV treatment, making earlier treatment attractive to some once more.
Further information on this website
Structured treatment interruption - overview of key research
Should treatment breaks be guided by CD4? Study suggests yes - news story September 15, 2003.
Week on, week off treatment strategy buried at Paris conference - news story, July 17, 2003.
Maggiolo F et al. Individualized structured treatment interruptions: results of a randomised controlled study (BASTA). 43rd ICAAC, abstract H-448, Chicago, September 14 – 17th, 2003.