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Antimicrobials during Pregnancy
Published in “Bert” Bertis Britt Little, Drugs and Pregnancy, 2022
Tenofovir is an antiviral used to treat hepatitis B infection. The drug was used in 3,715 first-trimester pregnancies, and the frequency of birth defects was not increased (Antiretroviral Registry, 2018). It is reported to account for 15 percent of pregnancies exposed to antivirals.
Entecavir
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Because of dual activity against both viruses, tenofovir is usually preferred as part of a comprehensive antiviral regimen in such patients. However, HIV and HBV co-infected patients who have had their HIV infection controlled by combination antiretroviral therapy can safely have entecavir added to treat the HBV infection (Pessoa et al., 2008; Piroth et al., 2015).
TRIPS Flexibilities and Access to Patented Medicines in India
Published in Hans Löfgren, The Politics of the Pharmaceutical Industry and Access to Medicines, 2017
In September 2009, the patent office in New Delhi refused a patent, on the grounds of evergreening, for the Aids drug Tenofovir Disoproxil Fumarate (TDF) filed by US company Gilead Sciences (Business Standard 2009). This drug was also refused patent in the United States, but the company’s strategy before the award decision in India is worth noting. Tenofovir is highly recommended by the WHO for the treatment of HIV/AIDS. In developing countries, Gilead’s patent-protected Tenofovir sold for $5,718 per patient, per year. In 2007 Gilead entered into an agreement with eleven Indian companies to manufacture and sell Tenofovir in ninety-five countries, using Gilead’s technology. Local producers could produce Tenofovir subject to payment of royalties, and on the condition that the drug would not be sold in certain countries, for example, Brazil and China (IDMA 2009). Licensed sellers of Tenofovir were also required to buy the active ingredients from Gilead’s affiliated licensed suppliers. Concerned by these restrictive clauses, CIPLA refused Gilead’s licensing offer and filed a pre-grant opposition on the grounds of evergreening and that granting the patent would lead to non-affordability of the drug worldwide (International drugmart.com 2010). As a pre-existing molecule—TDF is created by the addition of a salt (fumaric acid) to the existing compound, tenofovir disproxil—Tenofovir should not have been eligible for patent. Civil society groups had also filed pre-grant oppositions, joined for the first time by a foreign advocacy group—the Brazilian Interdisciplinary AIDS Association—since India’s granting of a patent would have affected access to Tenofovir in Brazil as well. In September 2009 the Delhi patent office refused the patent on Tenofovir, which meant that consumers could purchase the generic version at approximately $700 a year.
Safety of current antiviral drugs for chronic hepatitis B
Published in Expert Opinion on Drug Safety, 2022
Chiara Masetti, Nicola Pugliese, Alessio Aghemo, Mauro Viganò
Because of mitochondrial toxicity, oral nucleos(t)ide analogues can potentially lead to adverse fetal outcomes. ETV has been classified as class C medication by FDA, as large and well-controlled studies are lacking in pregnant women. Conversely, in animal and human studies, TDF was not associated with increased harm to the fetus, with reported newborn defect rates similar to the general population [42,43]. As a consequence, TDF is now the only approved drug during pregnancy by current European guidelines [2]. In all pregnant women already in treatment with NUCs, TDF can be safely continued while patients on ETV treatment should be switched to TDF. In HBsAg patients with HBV-DNA > 200,000 UI/mL, TDF should be started at week 24–28 of gestation and continued for up to 12 weeks after delivery. It has been demonstrated that only small amounts of tenofovir are detected in breast milk. Because of low bioavailability, the plasma concentration of TDF in newborns due to ingestion seems negligible, so as breastfeeding is not contraindicated during treatment with TDF [44]. In a recent study on 72 pregnant women who were randomized to receive TDF or TAF, drug levels were undetectable in breast milk samples in all patients in the TAF group, suggesting that this drug could be even safer than TDF in this subgroup of patients [45].
Pharmacotherapy options for managing hepatitis B in children
Published in Expert Opinion on Pharmacotherapy, 2021
Haruki Komatsu, Ayano Inui, Sachiyo Yoshio, Tomoo Fujisawa
Tenofovir DF is an oral prodrug of tenofovir which is a nucleotide analogue. After absorption, tenofovir is converted to the active metabolite, tenofovir diphosphate. After incorporating HBV DNA, tenofovir inhibits the elongation of viral minus strand DNA [6,95,96]. Tenofovir DF has antiviral activity against HBV and HIV. In a randomized placebo-controlled trial (Table 5), there was a significant difference in the virologic response (HBV DNA ˂400 copies/mL) between adolescents with tenofovir DF (89%) and placebo controls (0%) at the end of 72 weeks of treatment [97]. Although 85% of the adolescents had a history of antiviral therapy (IFN, lamivudine, adefovir, or entecavir), the suppression of HBV DNA was not influenced by prior HBV treatment. Normalization of the ALT level occurred at a significantly higher rate in the adolescents receiving tenofovir DF (74%) than in placebo controls (31%) at the end of 72 weeks of treatment. However, there was no significant difference in the rate of HBeAg loss between the adolescents treated with tenofovir DF (21%) and the placebo controls (15%). No resistance to tenofovir DF developed through 72 weeks of treatment. Adverse events were less in the tenofovir DF group than in the placebo group.
Synthetic therapeutics for the treatment of hepatitis B during pregnancy
Published in Expert Opinion on Pharmacotherapy, 2018
Premashis Kar, Anando Sengupta
HBV infection in pregnancy should be treated keeping in mind the phase of disease, risk of maternal to child transmission, as well as maternal and fetal adverse effects of antiviral therapy. In mothers with mild disease (not on antivirals), HBV DNA, ALT, and HBeAg should be retested at the end of the second trimester, and if indicated, antivirals should be started to lower viral load prior to delivery. Tenofovir is the preferred drug nowadays in pregnancy used for treating immune-active disease, cirrhotics, or to prevent MTCT. LAM or LdT may also be used to prevent MTCT; however, they have low barrier to resistance and safety concerns. Mothers should be strictly monitored postdelivery to detect flares or decompensation. Cirrhotics or patients in immune-active phase need to be identified early and treated throughout pregnancy.