Background: Increasingly cure trials require a treatment interruption (TI) in order to evaluate whether an intervention has worked. In order to ensure that future TI trials are designed sensitively with participants at the heart of the process, we carried out qualitative interviews with individuals taking part in the PITCH TI study.

Method: We recruited participants with primary HIV infection, who commenced ART within three months of diagnosis, have been on ART for at least two years with HIV‐1 DNA levels <3.25 log copies/million CD4 T cells, CD4 count >500 or CD4:8 ratio> 1, with suppressed plasma VL < 50 copies HIV RNA/ml.

Upon ART cessation, for the first 12 weeks participants were required to undergo point‐ of‐care quantitative GeneXpert viral load testing on a twice per week basis, with additional visits if desired. In‐depth qualitative face‐to‐face interviews were conducted two weeks before, at least two weeks during and two weeks after TI. The interviews aimed to explore views and experiences about TI.

Results: Five out of six participants participated: n=3 were interviewed before TI, n=5 were interviewed during TI and n=4 were interviewed after TI.

Seven themes were identified: 1) Motivation to participate: all participants reported participation in TI was to help others in future. 2) Benefits of TI: Stopped experiencing ART side effects and being off treatment saved NHS money. 3) Challenges of TI: frequent appointments with NHS for blood test. 4) Risks associated with TI: passing on HIV if detectable. Participants used prevention tools (PrEP/condoms). 5) Vicious cycle of worry: anxious/worried their viral load was going up and that they might transmit HIV. 6) Being undetectable: participants knew that undetectable=untransmittable. 7) Treatment rotation: TI is not a cure butswapping treatment with the partner who has to take PrEP.

Conclusion: Participants found that taking a TI as part of a cure trial to be a positive experience and valued the break from taking treatment every day. However psychosocial consideration should be incorporated into planning for TI studies including family/partner involvement. TI studies should provide PrEP to partners of participants as a risk reduction tool and have strategies to reduce participant anxiety during the TI phase.