Background: The MaxCmin1 trial is the first head-to-head comparison of ritonavir (r)-boosted PI treatments. MaxCmin1 primarily compares the virological failure rate at 48 weeks for the indinavir(IND)/r arm relative to the saquinavir(SAQ)/r arm.

Methods: Open-label, randomised (1:1), multicentre, phase IV trial evaluating the safety and efficacy of IND/r (800/100-mg BID) versus SAQ/r (1000/100-mg BID) in adult HIV-1-infected patients with clinical indication for a ritonavir-boosted PI regimen. Use of NRTI/NNRTI was decided prior to randomisation by the treating physician. One scheduled intention-to-treat (ITT) interim analysis was done on all week-24 data from subjects exposed to the study drugs. The ITT analysis was done using the Peto method of repeated significance with a significance level of 0.001.

Results: Beginning September 2000, 317 patients were randomised of whom 306 initiated treatment. Patients are primarily Caucasian (83%) men (78%) infected through sex with other men (49%). At 24 weeks, 13% (IND/r) vs 16% (SAQ/r) experienced virological failure. No difference was seen in viral suppression through 24 weeks (table). At weeks 4, 12, and 24, the CD4 T-cell count increase from baseline was 30, 43, and 40 (IND/r) and 33, 42, and 58 cells/mm³ (SAQ/r). Time to increase of >100 CD4 T cells/mm³ was 13 (12) weeks mean (median; n=69) for IND/r and 12 (5) weeks mean (median; n=62) for SAQ/r. No statistically significant difference was seen between the study arms in number (%) of grade 3/4 adverse events (AEs).

 

Table 1 % with HIV-1 RNA < 100 copies/mL

	SAQ/r (N =148) %	IND/r (N = 158) %
Baseline	36	35
Week 4	48	47
Week 12	66	61
Week 24	71	66

 

Conclusions: In the interim analysis at 24 weeks of this randomised trial no differences were observed in virological or immunological response to the 2 ritonavir-boosted study PIs nor in the proportion of patients with grade 3/4 AEs. No changes are warranted in the conduct of the trial following the Data and Safety Monitoring Board’s evaluation of the week 24 data. Final results available in third quarter 2002.