1091. Modeling of the effect of an integrase inhibitor based antiretroviral treatment regimen administered as a single tablet regimen on obstetrical target outcomes
Session: Poster Abstract Session: HIV: Modeling and Education Around Antiretrovirals
Friday, October 9, 2015
Room: Poster Hall
Background:

Routine opt-out HIV testing is recommended for pregnant women both early and in the 3rd trimester. Repeat testing in the 3rdtrimester improves case finding but often only leaves a short time to achieve viral suppression prior to delivery.  Guidelines recommend that HIV-positive pregnant women undergo scheduled week 38 cesarean delivery (CD) if the HIV viral load (VL) is > 1000 copies/ml. While early CD results in decreased mother-to-child transmission, it is associated with increased feto-maternal complications and potential HIV exposure to healthcare personnel.

Methods:

This study re-analyzed  2 pivotal phase 3 trials, which compared the once-daily regimens of co-formulated emtricitabine/tenofovir DF (FTC/TDF)/elvitegravir/cobicistat (EVG, n=701) with either FTC/TDF plus ritonavir-boosted atazanavir (ATVr, n=355) or co-formulated FTC/TDF/efavirenz (EFV, n=352) focusing on time to reaching a VL <1000 copies/ml, the cutoff for scheduled CD. Proportions of subjects in whom VLs declined to <1000 copies/ml in each treatment group were examined using chi-square tests.

Results:

The proportion of subjects in whom VL dropped to <1000 copies/ml by week of treatment is shown in table 1. Controlling for race, gender, and ethnicity did not alter results. Results stratified by baseline VL are available and will be presented at the conference.

Conclusion:

The initial choice of an ART regimen for women diagnosed with HIV in late pregnancy is predicted to have a significant impact on the need for scheduled CD, including an almost 40% reduction in the need for scheduled CD in patients treated with the integrase-inhibitor based single tablet regimen (EVG) evaluated in this model when compared to a perinatal guideline recommended PI-based regimen (ATVr) after 2 weeks of therapy. The discrepancies between the regimens are even more pronounced in certain subgroups such as patients with high VLs at baseline. If confirmed, the findings could have policy implications for pregnant women with HIV infection. Additional safety and pharmacodynamics studies are required, however, before the use of EVG can be recommended in pregnancy.

Table 1

                                                                      Viral load <1000 copies/ml in percent

 

Week 2

Week 4

Week 8

Week 12

EVG

90.9

98.1

98.5

98.4

ATVr

51.5

76.7

93.6

98.5

EFV

70

88.5

95.0

96.7

p value

<0.0001

<0.0001

<0.0001

0.1536

Sharon Weissman, MD1, Medha Iyer, M.D., Ph.D.2, Divya Ahuja, MD1, Rajeev Bais, MD1, Babatunde Edun, MD1, Julie Ann Justo, Pharm D, MS3, Caroline Derrick, PharmD4, Kiran Patel, RPh5 and Helmut Albrecht, MD6, (1)University of South Carolina, Columbia, SC, (2)Department of Health Services Policy and Management, University of South Carolina,Arnold School of Public Health, Columbia, SC, (3)Department of Clinical Pharmacy and Outcomes Science, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, (4)School of Pharmacy, University of South Carolina, Columbia, SC, (5)Gilead Pharmaceuticals, Foster City, CA, (6)Department of Medicine, Division of Infectious Diseases, University of South Carolina School of Medicine, Columbia, SC

Disclosures:

S. Weissman, None

M. Iyer, None

D. Ahuja, None

R. Bais, None

B. Edun, None

J. A. Justo, None

C. Derrick, None

K. Patel, Gilead Pharmaceuticals: Employee and Shareholder , Salary

H. Albrecht, Gilead: Investigator and Scientific Advisor , Research grant

Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.