Table 1A.

Summary of the outcome measures of efficacy assessed in therapeutic HIV vaccine clinical trials with analytical treatment interruptions: protein or peptide subunit vaccines

Vaccine	Study design	Primary outcome measure(s)	Other relevant efficacy outcome measures	Main findings	References
Vacc-4x (a mixture of four p24-like peptides)	Open, prospective RCT comparing low vaccine dose vs. high vaccine dose (no ATI during this phase of study)	Safety	CD4 T cell count CD8 T cell count	The higher dose of the vaccine induced stronger HIV-specific DTH and CD4 and CD8 T cell responses than the lower dose.	[136]
	Observation period of 26 weeks following immunization period in Ref. [136] that included two ATIs, one of four weeks’ duration and one of 14 weeks	Viral load ratio (end of study viral load/pre-ART viral load set point) Immunogenicity	CD4 T cell count CD8 T cell count	Participants with the highest DTH responses before ATI had lower VL by the end of the study compared to participants with low DTH responses.	[137]
	Long-term observation (1.5 years) after immunization in Ref. [136]	Percentage of participants who resumed ART Immunogenicity	CD4 T cell count pVL	Participants with the greatest DTH responses following immunization were less likely to require ART resumption compared to low responders.	[138]
	Observation period four years after enrolling in Ref. [136]	Time until ART resumption Immunogenicity	CD4 T cell count CD8 T cell count pVL Percentage of participants who resumed ART	Participants with the greatest DTH responses following immunization resumed ART later than low responders.	[139]
	RCT	Percentage of participants who met the criteria to resume ART Percent change in CD4 T cell count between the start of the ATI and the last CD4 T cell count before ART was resumed or the end of the study if ART was not resumed	Time to restart ART CD4 T cell count CD8 T cell count Pre-ART viral load set point (when available)* Viral load set point during ATI* *substudy	The vaccine had no effect on the proportion of participants who resumed ART or on changes in the CD4 T cell count during the ATI. However, vaccinated participants had significantly reduced viral load set points during ATI compared to controls.	[111]
TUTI-16 (synthetic HIV-1 Tat epitope)	RCT	Safety	Prevention of viral rebound following ATI CD4 T cell count	The vaccine did not prevent viral rebound following ATI.	[140]
LFn-p24C (subtype C HIV Gag protein p24 fused to a detoxified anthrax-derived polypeptide)	Open label, single-arm study; phase 1A: three immunizations; phase 1B: booster + ATI	Safety	CD4 T cell count Percentage of participants who did not experience viral rebound	Immunized participants had significantly higher CD4 T cell counts compared to historical controls 12 months after enrolment in phase 1A and 30% of participants did not experience any viral rebound following ATI in phase 1B.	[141]