1549. HIV Treatment Failure and Acquired Drug Resistance after One Year on Antiretrovirals in the Philippines
Session: Poster Abstract Session: HIV: Treatment Failure
Friday, October 28, 2016
Room: Poster Hall
Posters
  • Salvana ADR.pdf (678.2 kB)
  • Background:

    The Philippines has one of the fastest growing HIV epidemics globally. As antiretroviral (ARV) use increases, the risk of acquired drug resistance (ADR) grows. Only 7 ARV agents are widely available locally (Table 1).  The objectives of this study are to look at the rate of viral suppression after one year on ARVs, and to determine rates of resistance to specific ARVs.

    Methods:

    Following institutional board review, patients on ARVs for one year from 3 of the largest HIV treatment hubs (San Lazaro Hospital, the Philippine General Hospital and Vicente Sotto Hospital) were recruited. Blood samples underwent HIV viral load testing at a national reference laboratory (SACCL-NRL). Samples with >1000 copies/mL were sent to UP-NIH for genotyping and drug resistance testing.

    Results:

    458 patients (13 female, 445 male) with a median age of 30 years (range 1-72) were recruited. Median CD4 count was 298 cells/μL (range 3-1608). The most common regimens were TDF+3TC+EFV (236), AZT+3TC+EFV (135),  and AZT+3TC+NVP (52).  45 (9.8%) patients were not virally suppressed [median viral load 130,000 copies/mL (range 1,150 to 3,410,000)].  14 of the 45 unsuppressed subjects admitted missing pills in the past year. Failure rates for NVP-based regimens (15.9%) were significantly higher than for EFV-based regimens (8.6%)(p= 0.048).

    Genotypes in  unsuppressed subjects were CRF01_AE (84%), B (13%) and G (2%). No baseline genotype was available. 39 patients had clinically significant resistance mutations. The most common resistance mutations were M184V (22), K65R (18), Y181C (13), K101E (10), and K103N (9). 3 patients had a single PI mutation each (G48R, L33F, M46I). Resistance rates are shown on Table 1. 26/45 (58%) patients did not have an appropriate local second line regimen of three active drugs.

    Table 1.

    Locally available ARVs

    Resistance in Unsuppressed (%) N=45

    Overall % Resistance

    N=458

    AZT

    10 (22)

    2.2

    3TC

    34 (76)

    7.4

    TDF

    23 (51)

    5.0

    D4T

    27 (60)

    5.9

    NVP

    39 (87)

    8.5

    EFV

    39 (87)

    8.5

    LPV/r

    0 (0)

    0

    Conclusion:

    HIV viral suppression on ARVs is 90.2% at 1 year in the Philippines. NNRTIs are the least durable, and more agents are needed for second-line treatment. Treatment failure cannot be explained by compliance alone, and may be from transmitted drug resistance, which needs investigation.

    Edsel Maurice Salvana, MD, DTM&H, FIDSA1,2, Brian Schwem, PhD2, Genesis Samonte, MD3, Rosario Tactacan-Abrenica, MD4, Elizabeth Telan, MD5, Kevin Mendoza, RN3, Geraldine Arevalo, BS2, Marissa Alejandria, MD, MSc, FPCP, FPSMID1, Katerina Leyritana, MD1,6, Lyka Trinidad, RN3 and Jodor Lim, MD, FPCP, FPSMID1, (1)Department of Medicine, Section of Infectious Diseases, University of the Philippines - Philippine General Hospital, Manila, Philippines, (2)Institute of Molecular Biology and Biotechnology, National Institutes of Health, University of the Philippines (UP-NIH), Manila, Philippines, (3)Epidemiology Bureau, Department of Health, Republic of the Philippines, Manila, Philippines, (4)San Lazaro Hospital, Department of Health, Manila, Philippines, (5)STD and AIDS Cooperative Center Laboratory (SACCL), San Lazaro Hospital, Department of Health, Manila, Philippines, (6)Sustained Health Initiatives of the Philippines, Mandaluyong, Philippines

    Disclosures:

    E. M. Salvana, MSD: Speaker's Bureau , Speaker honorarium

    B. Schwem, None

    G. Samonte, None

    R. Tactacan-Abrenica, None

    E. Telan, None

    K. Mendoza, None

    G. Arevalo, None

    M. Alejandria, None

    K. Leyritana, None

    L. Trinidad, None

    J. Lim, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.