Hepatitis C pharmacogenetics: state of the art in 2010.

In 2009, a correlated set of polymorphisms in the region of the interleukin-28B (IL28B) gene were associated with clearance of genotype 1 hepatitis C virus (HCV) in patients treated with pegylated interferon-alfa and ribavirin. The same polymorphisms were subsequently associated with spontaneous clearance of HCV in untreated patients. The link between IL28B genotype and HCV clearance may impact decisions regarding initiation of current therapy, the design and interpretation of clinical studies, the economics of treatment, and the process of regulatory approval for new anti-HCV therapeutic agents.

An Evaluation of US Food and Drug Administration's Program to Register HIV Drugs for Use in Resource-Constrained Settings.

Importance: The US Food and Drug Administration (FDA) program to review antiretroviral drugs for use in low-resource settings via the US President's Emergency Plan for AIDS Relief (PEPFAR) now supports treatment of more than 14 million patients with HIV. However, an in-depth evaluation of the program has not been undertaken. Objective: To conduct a quantitative analysis of the FDA-reviewed antiretroviral drug applications in order to assess the contributions of PEPFAR and to identify areas for improvement. Design, Setting, and Participants: A cross-sectional study was conducted of all PEPFAR applications submitted to the FDA from December 1, 2004, to May 31, 2018. The analyses were conducted between October 2018 and February 2019. Main Outcomes and Measures: Numbers and types of applications reviewed, how long it took for applications to obtain approval or tentative approval (time to registration), how often the FDA issued a complete response letter (CRL) identifying deficiencies precluding application approval or tentative approval and their reasons, and the association between CRLs and time to registration. Results: Overall, 260 PEPFAR applications for 327 antiretroviral therapies were reviewed by FDA, of which 216 applications (83%) for 272 drugs were authorized for use. Of the 216 authorized applications, 184 applications for 231 drugs remain in active status and, thus, are available for use. Twenty-six percent (56 of 216) of the applications were for pediatric-specific formulations or strengths; the remainder were for adults. For all 216 applications, the median (interquartile range) time to registration was 10.0 (7.0-17.5) months. Thirty-seven percent (95 of 260) of the applications received 1 or more CRLs, resulting in a total of 172 CRLs; most applications received 1 CRL, whereas some were issued up to 6 CRLs. Among all CRLs, 264 deficiency reasons were identified; the most common deficiencies were associated with manufacturing processes (155 [44%]), followed by product labeling (62 [23%]), and failing facility inspections (54 [20%]). Complete response letters were associated with an increased time to registration. Applications without CRLs had a median (interquartile range) time to registration of 9.0 (5.5-12.0) months, whereas those with at least 1 CRL took a median (interquartile range) of 22.0 (14.0-38.0) months (P < .001). Conclusions and Relevance: The FDA's PEPFAR program has made many antiretroviral drugs available for global use. However, FDA and the pharmaceutical companies could take steps to improve the quality of applications submitted to prevent avoidable deficiencies in manufacturing processes and labeling. Further efforts to develop better, easier to use pediatric-specific therapies are needed.

Impact of the US Food and Drug Administration registration of antiretroviral drugs on global access to HIV treatment.

BACKGROUND: Since 2004, the US Food and Drug Administration's (USFDA) dedicated drug review process in support of President's Emergency Plan for AIDS Relief (PEPFAR) has made safe, effective and quality antiretrovirals (ARVs) available for millions of patients. Furthermore, the WHO and Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund) can add the USFDA-reviewed products to their respective formularies, through a novel process of 'one-way reliance'. We assessed the number of ARVs made available through WHO and Global Fund based on the USFDA review. METHODS: We conducted a cross-sectional study of all the USFDA-reviewed PEPFAR drugs between 1 December 2014 and 20 March 2017 to determine 1) the percentage that are included on the WHO and Global Fund formularies; 2) the number of the USFDA ARVs supporting the WHO HIV treatment guidelines, and their uptake by WHO and Global Fund and 3) time between the USFDA review and WHO review of the same ARVs. FINDINGS: Overall, 91% (204/224) of the USFDA products appeared on either the WHO/Prequalification of Medicines Programme (PQP) or the Global Fund ARV lists. Forty-five per cent (100/224) and 83% (184/224) appear on WHO/PQP and Global Fund formularies through one-way reliance, respectively. Forty-one per cent (91/224) of the USFDA products support the WHO-preferred first-line HIV treatment options. Of these 91 products, 38% and 85% of products were adopted by WHO/PQP and Global Fund through one-way reliance, respectively. Sixty-six products that were fully reviewed and registered by WHO (vs one-way reliance) had also undergone the USFDA review; 46 of these were registered by WHO after the USFDA review was complete (median delay of 559 days (IQR 233-798 days)). CONCLUSIONS: The USFDA's PEPFAR process is making safe and effective ARVs available worldwide, in part because the major global ARV procurement organisations rely on the USFDA registration as proof of quality. There is room for improved information sharing and collaboration to reduce duplication of effort, save resources and further expedite access to ARVs.

The US Food and Drug Administration's tentative approval process and the global fight against HIV.

INTRODUCTION: In 2004, the US government began to utilize the Food and Drug Administration's (USFDA) tentative approval process (tFDA) as a basis to determine which HIV drugs are appropriate to be purchased and used in resource-constrained settings. This process permits products that are not approved for marketing in the US, including medicines with active patents or marketing restrictions in the US, to be purchased and distributed in resource-constrained settings. Although the tFDA was originally intended to support the United States' President's Emergency Plan for AIDS Relief (PEPFAR), the USFDA list has become a cornerstone of international HIV programmes that support procurement of ARVs, such as the World Health Organization and the Global Fund to Fight AIDS, Tuberculosis, and Malaria. Our objective in this article is to help the global HIV policy makers and implementers of HIV programmes better understand the benefits and limitations of the tFDA by providing an in-depth review of the relevant legal and regulatory processes. DISCUSSION: USFDA's dedicated tFDA process for ARVs used by the PEPFAR programme has a wide impact globally; however, the implementation and the regulatory processes governing the programme have not been thoroughly described in the medical literature. This paper seeks to help stakeholders better understand the legal and regulatory aspects associated with review of ARVs under the tFDA by describing the following: (1) the tFDA and its importance to global ARV procurement; (2) the regulatory pathways for applications under tFDA for the PEPFAR programme, including modifications to applications, review timelines and costs; (3) the role of US patents, US marketing exclusivity rights, and the Medicines Patents Pool in tFDA; and (4) an overview of how applications for PEPFAR programme are processed through the USFDA. We also provide a case study of a new ARV, tenofovir alafenamide fumarate (TAF), not yet reviewed by USFDA for PEPFAR use. CONCLUSIONS: In this paper, we describe the importance and implementation of USFDA's tentative approval process to review ARVs for resource-constrained settings. We also highlight the impact of patents and exclusivities on review of HIV drugs under tFDA and illustrate the concepts using a new HIV drug as an example.

Meta-analysis of gender differences in efficacy outcomes for HIV-positive subjects in randomized controlled clinical trials of antiretroviral therapy (2000-2008).

Women are often underrepresented in randomized clinical trials (RCT) of HIV-1 drugs. As a result, determining whether women have different virologic outcomes compared to men is not always possible because the gender-related analyses usually lack statistical power. To address this important public health concern, the Food and Drug Administration's (FDA) Division of Antiviral Products (DAVP) created a database including 20,328 HIV-positive subjects from 40 RCTs in 18 New Drug Applications (NDAs) submitted to the FDA between 2000 and 2008. These RCTs were conducted for at least 48 weeks in duration and were used to support approval of new molecular entity, new formulation, or major label change. To delineate potential gender differences in antiretroviral treatment (ART), we evaluated the percentage of subjects with HIV RNA less than 50 copies per milliliter at 48 weeks. Analyses of the database represent the most systematic review of gender-related ART efficacy data to date. Overall, the meta-analyses did not demonstrate statistically or clinically significant gender differences in virologic outcome at week 48. However, the corresponding subgroup analyses appear to show several statistically significant gender differences favoring males.

Running a tightrope: regulatory challenges in the development of antiretrovirals.

Since the approval of Retrovir, (zidovudine, AZT) in 1987 by the Food and Drug Administration, a number of regulatory initiatives were codified into regulation which contributed to the rapid development of new treatments for HIV-1 infection. These initiatives are a testament to the efforts of AIDS activists and regulators to improve access to drugs for serious and life-threatening diseases. Currently, 28 antiretroviral drugs and combinations of antiretrovirals are available to treat HIV-1 infection. The broadening armamentarium of approved antiretroviral drugs provides new options and more choices for physicians and HIV patients. Importantly, the introduction of these newly approved HIV drugs has shown that the majority of HIV-1-infected treatment-naïve and treatment-experienced patients can achieve maximal virologic suppression (less than 50 copies/mL HIV-1 RNA). This article describes the past and current regulatory challenges in the development of new HIV treatments and provides an overview of the drug regulations that were required for the approval of HIV drugs. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.

Original research: Intravenous ribavirin--review of the FDA's Emergency Investigational New Drug Database (1997-2008) and literature review.

Intravenous (IV) ribavirin does not have US Food and Drug Administration (FDA) approval, although oral and aerosol formulations have been approved. Intravenous ribavirin can, however, be authorized for use as a result of an Emergency Investigational New Drug (EIND) application as investigational treatment for patients with serious viral infections, including emerging or rare infections for which no alternative treatment is available. This retrospective study evaluated clinical experience with IV ribavirin based on a review of the FDA's EIND database and a literature review. The main outcome measures were disease condition, clinical outcomes, and adverse events (AEs). First, the FDA's EIND database was evaluated for these variables among patients authorized to receive investigational IV ribavirin. Second, published literature on IV ribavirin was reviewed for diseases treated, reported clinical outcomes, and AEs. Adverse events reported in the literature were compared with AEs listed in approved product labeling (aerosol and oral formulations). From February 1997 to December 2008, 608 IV ribavirin EIND requests were made for 19 disease conditions. Adenovirus, respiratory syncytial virus, and parainfluenza infections comprised 84.7% of IV ribavirin EINDs. Inadequate reporting of clinical outcomes and AEs in the EIND database prevented analysis of either outcome. Data interpretation in the literature was limited by multiple factors, including retrospective design, small sample sizes, differences in reporting outcomes and AEs, lack of generalizability, and potential confounders such as concomitant medications, selection bias, and reporting bias. Reported AEs were consistent with labels of approved aerosol and oral formulations, except for lip and gingival swelling. However, estimates of frequency, severity, and causality of AEs associated with IV ribavirin could not be determined because of study limitations. Our study findings suggest that the literature is inconclusive on the potential benefit for continued use of IV ribavirin. A review of the literature and the FDA's EIND database suggests that prospective, controlled trials of IV ribavirin in patients with adenovirus, parainfluenza, or serious respiratory syncytial virus infections could be feasible.