You're testing in what?

Infection with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) still remains a significant public health concern, with 2.5 million new infections occurring annually. One of the primary treatments for the management of HIV/AIDS is the administration of antiretroviral (ARV) agents. ARV therapies (ART) have also proven effective in preventing viral infection via sexual transmission in high-risk populations¹. However, treatment success is impeded by lack of adherence as well as the potential development of multi-drug resistance. Recently, my group participated in a randomized, placebo-controlled trial to assess the use of oral (Truvada®, Gilead Sciences) or topical (1% tenofovir gel) ART for HIV prevention in South Africa, Uganda and Zimbabwe. Unfortunately, due to low adherence to study drugs, none of the ART regimens reduced rates of HIV-1 acquisition². These findings illustrate the challenges with adherence to daily drug regimens.

One mechanism, currently under investigation in a number of preclinical and clinical trials, to increase longitudinal drug adherence, is the topical application of vaginal or rectal microbicides. Such approaches may reduce adverse events while providing increased drug concentrations at the site of viral transmission. Compartmentalized PK studies are required to assess localized drug concentration in order to better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of ARVs in disease prevention and management. This requires further bioanalytical tools for the quantification of ARVs in matrices other than serum, including cervicovaginal secretions (CVS), rectal fluid (RF) and luminal tissue. Drug quantification in these matrices is not commonplace in routine laboratory settings; thus, my group has focused on the development and validation of liquid chromatographic-tandem mass spectrometric (LC-MS/MS) methods for the quantification of several ARVs in CVS³.

While the “Why?” has been answered; the question then remains: “How?” The objective, which involves quantification of non-nucleoside reverse transcriptase inhibitor dapivirine and the CCR5 antagonist maraviroc in CVS, is exciting for a laboratorian; it is a blank canvas to flex your analytical muscles. However, the devil is in the details, and the development of LC-MS/MS methods in niche matrices requires significant forethought. We took into consideration a number of factors, including acquisition of blank matrix (collected via an IRB-approved protocol), a goal analytical measuring range (dependent on route of drug administration), the minimum volume required (we are not dealing with traditional matrices, and therefore needed to be cognizant of specimen requirements) and how to sufficiently process and prepare a specimen before introducing it into the LC-MS/MS system. Upon optimization of these parameters for the aforementioned drugs, methods were validated in accordance with the Food and Drug Administration (FDA) Guidance for Industry, Bioanalytical Method Validation guidelines.

The bioanalytical development and validation of the aforementioned method was published in September 2014 in the Journal of Pharmaceutical and Biomedical Analysis³. However, more rewarding was to see the application of the described method in a phase 1 randomized trial assessing the safety, pharmacokinetics and pharmacodynamics of dapivirine and maraviroc applied topically⁴.

References

1. Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, et al. Prevention of HIV-1 Infection with Early Antiretroviral Therapy.  New Engl J Med. 2011 (365): 493-505
2. Marrazzo JM, Ramjee G, Richardson BA, Gomez K, Mgodi N….Marzinke MA et al., Tenofovir-based preexposure prophylaxis for HIV infection among African women. N Engl J Med. 2015 (327): 509-518.
3. Parsons TL, Emory JF, Seserko LA, Aung WS, Marzinke, MA.  Dual quantification of dapivirine and maraviroc in cervicovaginal secretions from ophthalmic tear strips and polyester-based swabs via liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis.  J Pharm Biomed Anal 2014 (98): 407-416.
4. Chen BA, Panther L, Marzinke MA, Hendrix CW, Hoesley CJ, et a., Phase 1 safety, pharmacokinetics, and pharmacodynamics of dapivirine and maraviroc vaginal rings: a double-blind randomized trial. J Acquir immune Defic Syndr. 2015 epub ahead of print.