CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

841 High Incidence of Syphilis Among Thai MSMWho Started ART Therapy During Acute HIV Infection Donn J. Colby 1 ; Suteeraporn Pinyakorn 1 ; Frits van Griensven 1 ; Eugene Kroon 1 ; Naphassanant Laopraynak 1 ; Robert O’Connell 2 ; Nelson L. Michael 2 ; Praphan Phanuphak 1 ; Jintanat Ananworanich 2 ; Nittaya Phanuphak 1 1 Thai Red Cross AIDS Research Center, Bangkok, Thailand; 2 US Military HIV Research Program, Bethesda, MD, US Background: Syphilis has been reported to increase HIV viral load (VL) among HIV-infected persons and can cause genital ulceration, potentially increasing the risk for HIV transmission. Worldwide, syphilis rates among men who have sex with men (MSM) have been increasing. Methods: We report syphilis prevalence and incidence in subjects enrolled during 2009-2014 in the RV254/SEARCH 010 cohort of acute HIV infection (AHI) in Bangkok, Thailand. VDRL is performed at baseline and every 48 weeks on all subjects, and in addition when clinically indicated. Positive results are confirmed with TPHA. CD4 testing, VL testing, clinical evaluation and HIV risk reduction counseling are performed every 12 weeks. Results: Among 188 persons with AHI median age was 28 years, 95%were male and 91.5%were MSM. Syphilis prevalence at baseline was 6.9% (n=13). Median (inter-quartile range, IQR) time from HIV risk exposure to HIV diagnosis was 16 (12-21) days in syphilis cases and 19 (14-25) days in subjects without syphilis (p=0.02). Pre-antiretroviral treatment (ART) median HIV VL (log 10 copies/ml) was 5.4 among syphilis cases and 5.8 among those without (p=0.04). Median (IQR) CD4 counts (cells/mm 3 ) were higher in those with syphilis at 534 (292-702) vs. 351 (257-481) (p=0.03). Incident syphilis occurred in 17% (n=32). Overall incidence (per 100 person-years) was 11.5, rising from 0 in 2009 to 16.7 in 2012 and 12.0 in 2014 (p=0.66). Patients with syphilis had less education than those without (49% vs. 66% university education, respectively, p=0.04). Among 31 patients with incident syphilis who were on ART and had a VL test at the time of diagnosis, 30 had plasma VL below 50 copies/ml and one had VL of 323 copies/ml. Mean CD4 count (cells/mm 3 ) was 606 at the time of incident syphilis diagnosis, a decline from 627 pre-syphilis (p=0.42), and rebounded to 678 (p=0.01) post-syphilis treatment. Conclusions: Syphilis is common among MSM in Bangkok at AHI diagnosis and during follow-up, with a rapid rise in incidence from 2009 to 2012. Baseline syphilis cases at AHI had higher CD4 counts and lower VL. Syphilis infection had no effect on HIV VL among those on ART but was associated with a transient and modest decline in CD4 count. Baseline and annual syphilis screening should be performed routinely on MSMwith HIV infection in Thailand. Regular counseling must include the risk of sexually transmitted infections from oral sex or skin-to-skin contact in addition to anal or vaginal sex without condoms. 842 Serological Response to Treatment of Syphilis in HIV-Positive and HIV-Negative Adults Rulin C. Hechter 1 ; Robyn Neblett Fanfair 2 ;W-L Joanie Chung 1 ; Lauri E. Markowitz 2 ; Sean S. Anand 1 1 Kaiser Permanente Southern California, Pasadena, CA, US; 2 US Centers for Disease Control and Prevention (CDC), Atlanta, GA, US Background: We assessed differences in serological response to syphilis treatment between HIV-positive (+) and HIV-negative (-) adults. Methods: We performed a cohort study of adults diagnosed with incident syphilis in Kaiser Permanente Southern California from 2006 to 2012. Inclusion into the study required new positive syphilis serologies, documented syphilis treatment and at least one follow-up rapid plasma reagin (RPR) titer within 12 months from the date of syphilis diagnosis. We ascertained demographic and clinical characteristics through electronic medical records. Response to syphilis treatment within 12 months was assessed among a subset of subjects with baseline RPR titer ≥ 1:16. Results: We identified 1062 HIV+ incident syphilis cases and 538 HIV- syphilis cases (Table 1). About 70% of the HIV+ cases were men who have sex with men. The median baseline RPR titer was 1:64 in HIV+ cases and 1:32 in HIV- cases; more HIV+ cases had a baseline RPR titer > 1:128 (20% vs. 8%). Among those with syphilis staging data, the majority of HIV- cases (51%) were diagnosed with a late latent syphilis, compared to only 8.4% of the HIV+ cases. Among HIV+ cases, 28% had a CD4 count ≤ 350 cells/mm 3 at syphilis diagnosis, and 73% had documented HAART use within 90 days of diagnosis. More HIV+ cases received benzathine penicillin G as the initial treatment of choice (91%) than HIV- cases (87%) ( P =.006). Among those with a baseline RPR titer ≥ 1:16 (797 HIV+ and 339 HIV- cases), HIV+ cases had a lower rate of serologic failure (5%) within 12 months compared to HIV- cases (10%). HIV- cases who received doxycycline as the initial treatment had a higher treatment failure rate (14%) than those treated with benzathine penicillin G (9%) ( P =0.36). Treatment failure rates were significantly ( P =.003) greater among HIV+ cases diagnosed with latent syphilis (early: 6%, late: 16%, respectively) than those with primary (1%) or secondary syphilis (3%). Treatment failure was associated with a baseline RPR titer <1:32 only in HIV- cases ( P =.007), but not in HIV+ cases.

Poster Abstracts

Table 1. Baseline Characteristics of Incident Syphilis Cases by HIV Infection Status—Kaiser Permanente Southern California, 2006-2012 Conclusions: We found HIV- cases were more likely to experience treatment failure and had a lower baseline RPR titer compared to HIV+ syphilis cases. The association between a lower baseline RPR titer and treatment failure in HIV- cases warrants further investigations

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CROI 2015

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