1. Antiretroviral Drug Switches in an Integrated TB and HIV Treatment Trial Anushka Naidoo, Kogieleum Naidoo, Tanuja Gengiah, Nesri Padayatchi, Aarthi Singh, Munira Khan, Shiela Bamber, Gonasagrie Nair, Nonhlanhla Yende, Salim Abdool Karim, on behalf of the SAPiT study team.

2. Overview Background Challenges of concomitant treatment of TB/HIV co- infection include drug-drug interactions and overlapping toxicities Study Design Retrospective analysis of 561 TB/HIV co-infected patients in the SAPiT trial initiated onto ART Objective Investigation of rates and reasons for switching of first line ART drugs in TB/HIV co-treatment.

3. Results Summary of Single Drug Switches: N=13 Initial DrugReason for SwitchNumber of switches Median Time to Switch* (months) Months to Switch per AE* Didanosine (ddI)Peripheral Neuropathy36 (4-11)4 (1-11) N=6Hyperlactaemia1 12 4 Pancreatitis1 8 Liver Abnormalities1 EfavirenzCNS/Neuropsychiatric35 (2-11)4 (0.5-6) N=4Pregnancy1 15 Zidovudine (AZT) Anaemia1 5 (2-8) 8 2 N=2Hyperlactaemia1 Nevirapine N=1 Hypersensitivity Rash (with Grade 3 ALT) 188 Changes to Second Line Regimens N=22 EFV/3TC/ddIVirological Failure2211 (9-12) * From ART initiation

4. Conclusion 6% of cohort switched from first line drugs –1.8% due to toxicity or contra-indication –4.2% due to virological failure Baseline peripheral neuropathy experienced 17 fold increased risk for single drug switches Low overall incidence of additive toxicities Low overall virological failure

5. Acknowledgements We thank, the individuals who guided, and supported the design and conduct of the trial, the University of KwaZulu-Natal Biomedical Research Ethics Committee and the South African Medicines Control Council for their oversight of the trial as well as participants, sponsors and CAPRISA eThekweni Treatment Team