Combined HIV Adolescent Prevention Study (CHAPS): comparison of HIV pre-exposure prophylaxis regimens for adolescents in sub-Saharan Africa—study protocol for a mixed-methods study including a randomised controlled trial

Table 2 Table of participant randomisation groups and laboratory analysis of foreskins

Stage 1: Oral PrEP taken by men						Foreskin tissue divided in the lab	Stage 2: In vitro dosing of tissue in the laboratory
Randomised arm	N	Oral PrEP analysis group	Oral drug	Number of PrEP doses	Interval between last oral PrEP and VMMC (h)		In vitro analysis group	In vitro drug	Interval between ex vivo HIV exposure and in vitro dose (h)
1	16	X	No PrEP	–	–		X-0	No PrEP	–
							X-TDF	FTC-TDF	18
							X-TAF	FTC-TAF	18
2	16	A	FTC-TDF	1	5		A-5-0	No PrEP	–
							A-5-TDF	FTC-TDF	18
3	16		FTC-TDF	1	21		A-21-0	No PrEP	–
							A-21-TDF	FTC-TDF	18
4	16	B	FTC-TDF	2	5		B-5-0	No PrEP	–
							B-5-TDF	FTC-TDF	18
5	16		FTC-TDF	2	21		B-21-0	No PrEP	–
							B-21-TDF	FTC-TDF	18
6	16	C	FTC-TAF	1	5		C-5-0	No PrEP	–
							C-5-TAF	FTC-TAF	18
7	16		FTC-TAF	1	21		C-21-0	No PrEP	–
							C-21-TAF	FTC-TAF	18
8	16	D	FTC-TAF	2	5		D-5-0	No PrEP	–
							D-5-TAF	FTC-TAF	18
9	16		FTC-TAF	2	21		D-21-0	No PrEP	–
							D-21-TAF	FTC-TAF	18

The in vitro analysis groups comprise three components: a letter indicating the stage 1 group, a number (5 or 21) indicating the interval between the last oral PrEP dose and circumcision and an item indicating in vitro dosing (where 0 = no dose). The exceptions are the group of men who did not receive oral PrEP (group X): these groups do not include the middle component

ISSN: 1745-6215