undetectable (undetectable-6.25) P1887 Skin Rash Related to Once-daily Boosted Darunavir-Containing Regimens in HIV-infected Taiwanese: Incidence and Associated Factor Kuan-Yin Lin1, Chien-Yu Cheng2, Chia-Jui Yang3, Mao-Song Tsai3, Szu-Min Hsieh1, Hsin-Yun Sun1, Wang-Huei Sheng1, Mao-Yuan Chen1, Sui-Yuan Chang1, Shu-Hsing Cheng2, Chien-Ching Hung1 1National Taiwan University Hospital, Taipei; 2Taoyuan General Hospital, Taoyuan; 3Far Eastern Memorial Hospital, New Taipei City, Taiwan Chien-Ching Hung, M.D., Ph.D E-mail: hcc0401@ntu.edu.tw Abstract Results Figure 1. Summary of DRV/RTV-related adverse effects in 238 patients 238 patients who switched to once-daily DRV/RTV-containing regimens (Group A) and 178 patients who switched from 2 NRTIs plus nNRTI or other PI to 2 NRTIs plus PI other than DRV/RTV (Group B) were included (Table 1). In per-protocol analysis, the proportion of patients with plasma HIV RNA load <50 copies/ml increased from 26.2% (62/237) at baseline to 70.8% (68/96) at week 24 and 82.7% (67/81) at week 48; the median CD4 cell count increased from 291 to 402 and 448 cells/μl at weeks 24 and 48, respectively. The mean duration of DRV/RTV exposure was 37.9 weeks, and 21.4% of the patients developed any grade of adverse effects (Figure 1). In multivariate analysis, the history of rash to the preceding nNRTI-containing regimens before switch was independently associated with DRV/RTV-related rash (Figure 2). Compared with Group A in which 26 patients (10.9%) developed rashes after switch to DRV/RTV-containing regimen, 7 patients (3.9%) in Group B experienced rashes after switch to PIs other than DRV (P=0.009). Objectives: To investigate the incidence of and associated factors with skin rashes among HIV-infected Taiwanese patients who received once-daily darunavir (DRV) boosted by ritonavir (RTV) (800/100 mg) plus 2 NRTIs. Methods: We reviewed the medical records of HIV-infected patients who switched to once-daily DRV/RTV-containing regimens in 2012-2013. Patients who switched from 2 NRTIs plus nNRTI or other PI to two NRTIs plus PIs other than DRV were chosen as comparators. Results: During the 2-year study period, 238 patients who switched to once-daily DRV/RTV-containing regimens (Group A) and 178 patients who switched from 2 NRTIs plus nNRTI or other PI to 2 NRTIs plus PI other than DRV/RTV (Group B) were included. Compared with Group B in which 7 (3.9%) developed rashes after switch to PI other than DRV, 26 patients (10.9%) in Group A developed rashes after a median interval of 14 days of starting DRV/RTV-containing regimens (P=0.009). In multivariate analysis, patients with a history of rashes related to the previous nNRTI-containing regimens before starting DRV/RTV-containing regimens were more likely to develop rashes with an adjusted odds ratio of 3.53 (95% CI, 1.45-8.62). Conclusions: Once-daily regimens containing DRV/RTV is associated with a higher rate of adverse cutaneous reactions than other PI-containing regimens in HIV-infected Taiwanese, especially in those who have a history of rashes to nNRTI-containing regimens before switch to DRV/RTV-containing regimens. Figure 2. Incidence for DRV/RTV-related skin rash in different groups (%) * AOR, 3.53 95% CI, 1.45-8.62 Table 1. Clinical characteristics of patients in Groups A and B. Baseline characteristics Group A (N=238) Group B (N=178) p Male, n (%) 230 (96.6) 171 (96.1) 0.757 Mean age, years (SD) 38.3 (10.1) 39.8 (10.9) 0.128 Men who have sex with men, n (%) 177 (74.4) 139 (78.1) 0.380 CDC class A, n (%) 205 (86.1) 159 (89.3) 0.621 Duration of HIV infection, mean (SD), years 4.6 (4.6) 4.7 (5.0) 0.487 Duration of ARV therapy, mean (SD), years 3.2 (4.2) 3.8 (4.6) 0.439 Baseline PVL, median (range), log10 copies/ml 5.04 (2.91-7.15) 4.97 (2.60-7.00) 0.279 Baseline CD4 count, median (range), cells/μl 200.0 (0-1230) 202.0 (0-980) 0.797 PVL at switch, median (range), log10 copies/ml 3.33 (undetectable-7.00) undetectable (undetectable-6.25) < 0.001 CD4 count at switch, median (range), cells/μl 291.0 (0-1336) 413.5 (2-1237) Comorbidity, n (%) HBV- or HCV-coinfected Hypertension Hyperlipidemia Diabetes mellitus Chronic kidney disease Chronic hepatitis 71 (29.8) 14 (5.9) 25 (10.5) 9 (3.8) 4 (1.7) 41 (17.2) 39 (21.9) 25 (14.0) 52 (29.2) 12 (6.7) 1 (0.6) 17 (9.6) 0.070 0.005 0.172 0.300 0.025 Introduction Once-daily DRV/RTV (800/100 mg) is the preferred regimen for antiretroviral-naïve and early antiretroviral-experienced patients without DRV resistance-associated mutations. While skin rash has been shown to develop in 3% of the patients who received DRV/RTV-containing regimens in clinical trials with rare discontinuation of the treatment, a recent observational study conducted in Japan reported a higher rate of skin rash occurring in 11% of the ARV-naïve patients who initiated DRV/RTV. We aimed to examine the incidence and risk factors of skin rash to DRV/RTV-containing regimens when DRV/RTV (800/100 mg) was introduced into clinical use in Taiwan in 2012. Conclusions Once-daily DRV/RTV (800/100 mg)-containing regimens cause a higher risk of skin rashes than other PI-containing regimens in HIV-infected patients who are ethnic Chinese. A history of skin rash to nNRTI before switch to DRV/RTV is independently associated with an increased risk of DRV/RTV-related skin rash (AOR, 3.53). More pharmacogenetic investigations are warranted. Methods Design: retrospective cohort study, 2012-2013. Study sites: 3 major designated hospitals for HIV care in northern Taiwan. 3. Subjects: switched to once-daily DRV/RTV (800/100 mg)-containing regimens. Comparators: switched from 2 NRTIs plus nNRTI or other PI to 2 NRTIs plus PIs other than DRV. 5. Primary endpoint: skin rash of any grade