Short-term administration of disulfiram for reversal of latent HIV infection: a phase 2 dose-escalation study

Abstract

Background: In vitro, disulfiram activated HIV transcription in a primary T-cell model of HIV latency and in a pilot clinical study increased plasma HIV RNA in individuals with adequate drug exposure. We assessed the effect of disulfiram on HIV transcription in a dose-escalation study.

Methods: In this prospective dose-escalation study, to optimise disulfiram exposure we included adults with HIV on suppressive antiretroviral therapy, with plasma HIV RNA of less than 50 copies per mL and a CD4 cell count greater than 350 cells per μL. Participants were allocated sequentially to one of three dosing groups (500 mg, 1000 mg, and 2000 mg) and received disulfiram daily for 3 days. Only the staff who did laboratory assays were masked to group assignment. The primary endpoint was change in cell-associated unspliced HIV RNA in CD4 cells. The primary analysis method was a negative binomial regression, with the number of copies as the outcome variable and the input total RNA or plasma volume as an exposure variable, which is equivalent to modelling copies or input. We used these models to estimate changes from before disulfiram to timepoints during and after disulfiram administration. This study is registered with ClinicalTrials.gov, number NCT01944371.

Findings: Of 34 participants screened for eligibility at The Alfred Hospital (Melbourne, VIC, Australia), and San Francisco General Hospital (San Francisco, CA, USA), 30 people were enrolled between Sept 24, 2013, and March 31, 2014. The estimated fold increases in cell-associated unspliced HIV RNA from baseline were 1·7 (95% CI 1·3-2·2; p<0·0001) to the timepoint during disulfiram treatment and 2·1 (1·5-2·9; p<0·0001) to the timepoint after disulfiram in the 500 mg group; 1·9 (1·6-2·4; p<0·0001) and 2·5 (1·9-3·3; p<0·0001) in the 1000 mg group; and 1·6 (1·2-2·1; p=0·0026) and 2·1 (1·5-3·1; p=0·0001) in the 2000 mg group. No deaths occurred, and no serious adverse events were noted. Disulfiram was well tolerated at all doses.

Interpretation: Short-term administration of disulfiram resulted in increases in cell-associated unspliced HIV RNA at all doses, consistent with activating HIV latency. Disulfiram may be suited for future studies of combination and prolonged therapy to activate latent HIV.

Funding: The Foundation for AIDS Research (amfAR); National Institute of Allergy and Infectious Diseases, National Institutes of Health; Australian National Health and Medical Research Council.

Figure 1. Study profile

Figure 2. Effect of disulfiram on CA-US HIV RNA in total CD4 T-cells and plasma HIV RNA

Fold change in CA-US and plasma HIV RNA following administration of disulfiram, from negative binomial regression with whiskers showing 95% confidence intervals. Each time point is compared to the mean of three pre-disulfiram time points. Disulfiram was administered at time 0, 24 and 48 hours (vertical black arrows). ***p<0·001; **p<0·01 – 0·001; *p<0·05 – 0·01.

Figure 3. Pharmacokinetic relationship between disulfiram dose and disulfiram drug concentration levels (ng/mL)

Disulfiram concentration-time curves for each dosing cohort demonstrate increases in plasma drug concentrations after disulfiram doses given on days 0, 1 and 2 with declines in drug levels thereafter up to day 7. The median cumulative area under the curve (AUC) values for the 500, 1000 and 2000 mg groups were 573, 2845, and 8355 mg-hr/L. Disulfiram given at 2000 mg demonstrated a 48% higher-than-dose-proportional increase in drug exposure compared to the 500 mg or 1000 mg groups.

Figure 4. Baseline variability in CA-US HIV RNA

Quantification at each of the three baseline time points: the screening visit (B1), the sample taken immediately prior to the first dose of disulfiram (B3) and a sample taken on a day between B1 and B3 (B2). A) Time of blood sampling; B) CA-US HIV RNA; C) Plasma HIV RNA; and D) HIV DNA. Central lines and whiskers indicate the mean and standard deviation (B); and median and 25th and 75th percentiles (A, C, D). ***p<0·001; **p<0·01 – 0·001; *p<0·05 – 0·01.