Chronic hepatitis B genotype E in African migrants: response to nucleos(t)ide treatment in real clinical practice

Background: Hepatitis B virus (HBV) genotype E is a poorly studied genotype that almost exclusively occurs in African people. It seems to harbour intrinsic potential oncogenic activity and virological characteristics of immune scape but a paucity of information is available on clinical and virological characteristic of HBV genotype E-infected patients as well as on the efficacy of anti-HBV drugs for such patients. The increasing flow of migrants from high endemic HBV sub-Saharan Africa, where genotype E is the predominant one, to Western countries makes improving such knowledge critical in order to deliver proper medical care. Methods: Prospective observational study of naive patients of sub-Saharan origin treated for chronic HBV genotype E infection at a Tropical Medicine clinic sited in Spain from February 2004 to January 2018. The aim of the study was to describe the response of chronic HBV genotype E infection to nucleos(t)ide analogues (NA), entecavir or tenofovir, in real clinical practice. Results: During the study period, 2209 sub-Saharan patients were assisted at our Tropical Medicine Unit and 609 (27.6%) had chronic HBV (CHB) infection. Genotype information was available for 55 naive patients initiating treatment with NA (entecavir or tenofovir), 43 (84.3%) of them being genotype E, although 15 were excluded because they did not meet study inclusion criteria. Thus, a total of 28 CHB genotype E patients were included and followed for 24 months at least. Twenty-one patients were in HBeAg-negative chronic hepatitis phase and 7 patients in HBeAg-positive chronic hepatitis phase. After one year of treatment, among those with good adherence, 89.4% (17/19) of the HBeAg-negative patients and 80% of the HBeAg-positive ones had undetectable viral loads. Response rates reached 100% in both groups after 15-18 months of follow-up. Out of the 7 HBeAg-positive patients, 6 (85.7%) presented HBeAg loss in a median time of 31.8 months. Neither serious adverse effects nor hepatocarcinoma cases happened during the study period. Conclusions: HBV genotype may influence disease progression and antiviral response. Our study provides precious information on the efficacy and safety of NA treatment for CHB genotype E infection, a fairly unknown genotype with and increasing epidemiological impact.