Using data from IeDEA-SA cohorts, Cleophas’s PhD work focused on antiretroviral drug resistance among patients failing protease inhibitor-based second-line treatment. HIV drug susceptibility for each participant was predicted using the Stanford algorithm and was categorized as susceptible, low level resistance, intermediate resistance, or high level resistance Furthermore, he assessed the factors associated with drug resistance mutations at second-line failure. He evaluated early treatment response to third-line treatment focusing mainly on viral, immunological and clinical outcomes. Outcomes was assessed at 24, 48 and 96 weeks post third-line commencement. He assessed the cost effectiveness of third-line treatment by extending our existing simulation model to compare different strategies after second-line ART failure similar to a previous modelling study done by Ouattara et al. Cleophas currently works as a Medical Officer at Newlands Clinic in Harare, Zimbabwe. Newlands Clinic is a private, not for profit organization run by Swiss AIDS Care International-Zimbabwe. The Clinic works in partnership with the Zimbabwe Ministry of Health and Child Care to provide comprehensive HIV treatment and Care to the vulnerable members of society at no cost to the patient.