Characteristics of hepatitis C virus resistance in an international cohort after a decade of direct-acting antivirals

Background & Aims: Direct-acting antiviral (DAA) regimens provide a cure in >95% of patients with chronic HCV infection. However, in some patients in whom therapy fails, resistance-associated substitutions (RASs) can develop, limiting retreatment options and risking onward resistant virus transmission. In this study, we evaluated RAS prevalence and distribution, including novel NS5A RASs and clinical factors associated with RAS selection, among patients who experienced DAA treatment failure. Methods: SHARED is an international consortium of clinicians and scientists studying HCV drug resistance. HCV sequence linked metadata from 3,355 patients were collected from 22 countries. NS3, NS5A, and NS5B RASs in virologic failures, including novel NS5A substitutions, were examined. Associations of clinical and demographic characteristics with RAS selection were investigated. Results: The frequency of RASs increased from its natural prevalence following DAA exposure: 37% to 60% in NS3, 29% to 80% in NS5A, 15% to 22% in NS5B for sofosbuvir, and 24% to 37% in NS5B for dasabuvir. Among 730 virologic failures, most were treated with first-generation DAAs, 94% had drug resistance in ≥1 DAA class: 31% single-class resistance, 42% dual-class resistance (predominantly against protease and NS5A inhibitors), and 21% triple-class resistance. Distinct patterns containing ≥2 highly resistant RASs were common. New potential NS5A RASs and adaptive changes were identified in genotypes 1a, 3, and 4. Following DAA failure, RAS selection was more frequent in older people with cirrhosis and those infected with genotypes 1b and 4. Conclusions: Drug resistance in HCV is frequent after DAA treatment failure. Previously unrecognized substitutions continue to emerge and remain uncharacterized. Lay summary: Although direct-acting antiviral medications effectively cure hepatitis C in most patients, sometimes treatment selects for resistant viruses, causing antiviral drugs to be either ineffective or only partially effective. Multidrug resistance is common in patients for whom DAA treatment fails. Older patients and patients with advanced liver diseases are more likely to select drug-resistant viruses. Collective efforts from international communities and governments are needed to develop an optimal approach to managing drug resistance and preventing the transmission of resistant viruses

The Burden of Neglected HIV-2 and HTLV-1 Infections in Spain.

HIV-2 and HTLV-1 infections are globally less frequent than those produced by HIV-1, the classical AIDS agent. In Spain and up to the end of 2014, a total of 310 cases of HIV-2, 274 of HTLV-1, and 776 of HTLV-2 infections had been reported. No cases of HTLV-3 or HTLV-4 infections have been identified so far in Spain. Most persons infected with HIV-2 or HTLV-1 acknowledge epidemiological risk factors for contagion, such as originating from or living in endemic regions and/or having had sexual partners from those areas. However, risk factors could not be recognized in up to 20-25% of carriers in Spain. Thus, it seems worth keeping a high level of clinical suspicion in order to identify earlier these neglected human retroviral infections, since diagnostic procedures and antiviral treatment are specific for each of these agents. In this article we summarize the major contributions reported at the meeting of the Spanish Group for HIV-2/HTLV held in Madrid in December 201