Tenofovir alafenamide: An initial experience at Groote Schuur Hospital, Cape Town, South Africa

BACKGROUND

Hepatitis B virus (HBV) remains endemic in South Africa (SA), with a concomitantly high prevalence of HIV co-infection. Chronic kidney disease in these subpopulations also has a high prevalence. Tenofovir is an important component of management, but the associated risk of nephrotoxicity makes dosing a challenge in patients with impaired kidney function. A new formulation, tenofovir alafenamide fumarate (TAF), with a more favourable renal toxicity profile, is now available.

OBJECTIVES

To evaluate our initial experience of TAF use at Groote Schuur Hospital, Cape Town.

METHODS

We retrospectively reviewed patients with HBV mono-infection and HIV-HBV co-infection who were initiated on TAF since 2018. We recorded all relevant demographic, serological, virological and biochemical data from patient records. Adherence was documented by pill collection at the pharmacy.

RESULTS

A total of 26 patients were included in the evaluation, median (interquartile range (IQR)) age 48 (39 - 51) years, 73% (n=19) male, 27% (n=7) hepatitis B e-antigen-positive, and 46% (n=12) HIV co-infected. The median (IQR) duration of treatment with TAF was 13 (9 - 15) months. The median (IQR) baseline creatinine level was 180 (130 - 227) µmol/L, with significant improvement at 12 months, 122 (94 - 143) µmol/L; p=0.017. Reflecting this change, the estimated glomerular filtration rate improved significantly from baseline to month 12 (42 (25 - 52) and 51 (48 - 68) mL/min/1.73 m2, respectively; p=0.023). Similarly, serum alanine aminotransferase (ALT) normalised from a baseline of 33 (18 - 52) to 18 (15 - 24) U/L at month 12 (p=0.012). HBV DNA viral load also declined, from a baseline of log10 4.04 (2.5 - 7.8) IU/mL to a median of <log10 1.3 IU/mL at month 12. HIV viral load was less than the lower level of quantification at months 6 and 12.

CONCLUSIONS

TAF was well tolerated, with stable and significantly improving kidney function throughout a 12-month follow-up period. Serum ALT normalised, mirrored by declining HBV viral load. HIV viral load remained undetectable at 6 and 12 months.

Detection of in vivo hepatitis B virus surface antigen mutations-A comparison of four routine screening assays

An important requirement for a state-of-the-art hepatitis B surface antigen (HBsAg) screening assay is reliable detection of mutated HBsAg. Currently, there is a striking shortage of data regarding the detection rates of in vivo HBsAg mutations for these clinically important assays. Therefore, we compared the detection rates of four commercial HBsAg screening assays using a global cohort of 1553 patients from four continents with known HBV genotypes. These samples, which represent the broadest spectrum of known and novel HBsAg major hydrophilic region (MHR) mutations to date, were analyzed for the presence of HBsAg using the Roche Elecsys^® HBsAg II Qualitative, Siemens ADVIA Centaur XP HBsAg II, Abbott Architect HBsAg Qualitative II and DiaSorin Liaison^® HBsAg Qualitative assays, respectively. Of the 1553 samples, 1391 samples could be sequenced; of these, 1013 (72.8%) carried at least one of the 345 currently known amino acid substitutions (distinct HBsAg mutation) in the HBsAg MHR. All 1553 patient samples were positive for HBsAg using the Elecsys^® HBsAg II Qual assay, with a sensitivity (95% confidence interval) of 99.94% (99.64%-100%), followed by the Abbott Architect 99.81% (99.44%-99.96%), Siemens ADVIA 99.81% (99.44%-99.96%) and DiaSorin Liaison^® 99.36% (98.82%-99.69%) assays, respectively. Our results indicate that the Elecsys^® HBsAg II Qual assay exhibits the highest sensitivity among the commercial HBsAg screening assays, and demonstrate that its capacity to detect HBV infection is not compromised by HBsAg MHR mutants.

Strategies to manage hepatitis C virus (HCV) infection disease burden - volume 2

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 15 countries, and the relative impact of two scenarios was considered: (i) increased treatment efficacy while holding the treated population constant and (ii) increased treatment efficacy and increased annual treated population. Increasing levels of diagnosis and treatment, in combination with improved treatment efficacy, were critical for achieving substantial reductions in disease burden. In most countries, the annual treated population had to increase several fold to achieve the largest reductions in HCV-related morbidity and mortality. This suggests that increased capacity for screening and treatment will be critical in many countries. Birth cohort screening is a helpful tool for maximizing resources. In most of the studied countries, the majority of patients were born between 1945 and 1985.

The present and future disease burden of hepatitis C virus (HCV) infections with today's treatment paradigm - volume 2

Morbidity and mortality attributable to chronic hepatitis C virus (HCV) infection are increasing in many countries as the infected population ages. Models were developed for 15 countries to quantify and characterize the viremic population, as well as estimate the number of new infections and HCV related deaths from 2013 to 2030. Expert consensus was used to determine current treatment levels and outcomes in each country. In most countries, viremic prevalence has already peaked. In every country studied, prevalence begins to decline before 2030, when current treatment levels were held constant. In contrast, cases of advanced liver disease and liver related deaths will continue to increase through 2030 in most countries. The current treatment paradigm is inadequate if large reductions in HCV related morbidity and mortality are to be achieved.

Historical epidemiology of hepatitis C virus (HCV) in select countries - volume 2

Chronic hepatitis C virus (HCV) infection is a leading cause of liver related morbidity and mortality. In many countries, there is a lack of comprehensive epidemiological data that are crucial in implementing disease control measures as new treatment options become available. Published literature, unpublished data and expert consensus were used to determine key parameters, including prevalence, viremia, genotype and the number of patients diagnosed and treated. In this study of 15 countries, viremic prevalence ranged from 0.13% in the Netherlands to 2.91% in Russia. The largest viremic populations were in India (8 666 000 cases) and Russia (4 162 000 cases). In most countries, males had a higher rate of infections, likely due to higher rates of injection drug use (IDU). Estimates characterizing the infected population are critical to focus screening and treatment efforts as new therapeutic options become available.