Ribavirin
A nucleoside analogue with broad-spectrum antiviral activity. It was used empirically in the Malaysian outbreak of Nipah virus (NiV) and in some cases of Hendra virus (HeV) infection.[50]Chong HT, Kamarulzaman A, Tan CT, et al. Treatment of acute Nipah encephalitis with ribavirin. Ann Neurol. 2001 Jun;49(6):810-3.
http://www.ncbi.nlm.nih.gov/pubmed/11409437?tool=bestpractice.com
[29]Playford EG, McCall B, Smith G, et al. Human Hendra virus encephalitis associated with equine outbreak, Australia, 2008. Emerg Infect Dis. 2010 Feb;16(2):219-23.
https://wwwnc.cdc.gov/eid/article/16/2/09-0552_article
http://www.ncbi.nlm.nih.gov/pubmed/20113550?tool=bestpractice.com
Although outcomes were improved in patients who received ribavirin in Malaysia, this therapy occurred at the end of the outbreak when the patients may have received better supportive care.[50]Chong HT, Kamarulzaman A, Tan CT, et al. Treatment of acute Nipah encephalitis with ribavirin. Ann Neurol. 2001 Jun;49(6):810-3.
http://www.ncbi.nlm.nih.gov/pubmed/11409437?tool=bestpractice.com
The efficacy of ribavirin was challenged by subsequent animal studies.[34]Broder CC, Xu K, Nikolov DB, et al. A treatment for and vaccine against the deadly Hendra and Nipah viruses. Antiviral Res. 2013 Oct;100(1):8-13.
http://www.sciencedirect.com/science/article/pii/S0166354213001691
http://www.ncbi.nlm.nih.gov/pubmed/23838047?tool=bestpractice.com
In one report of the 2018 Kerala NiV outbreak, there were 20% fewer cases of encephalitis among patients who received ribavirin, but the difference was not statistically significant.[38]Chandni R, Renjith TP, Fazal A, et al. Clinical manifestations of Nipah virus-infected patients who presented to the emergency department during an outbreak in Kerala State in India, May 2018. Clin Infect Dis. 2020 Jun 24;71(1):152-7.
http://www.ncbi.nlm.nih.gov/pubmed/31627214?tool=bestpractice.com
In the absence of other therapies, ribavirin may be considered in the treatment of henipavirus infection.[34]Broder CC, Xu K, Nikolov DB, et al. A treatment for and vaccine against the deadly Hendra and Nipah viruses. Antiviral Res. 2013 Oct;100(1):8-13.
http://www.sciencedirect.com/science/article/pii/S0166354213001691
http://www.ncbi.nlm.nih.gov/pubmed/23838047?tool=bestpractice.com
Further data need to become available to make recommendations for its use in henipavirus infection.
Human monoclonal antibodies
Passive immunotherapy with human monoclonal antibodies specific for viral glycoproteins may have a role in preventing infection in patients exposed to henipaviruses. In particular, the monoclonal antibody m102.4 has proven efficacy in post-exposure treatment in animal studies for both HeV or NiV and has been used in humans with high-risk exposures to HeV in Australia on compassionate grounds.[34]Broder CC, Xu K, Nikolov DB, et al. A treatment for and vaccine against the deadly Hendra and Nipah viruses. Antiviral Res. 2013 Oct;100(1):8-13.
http://www.sciencedirect.com/science/article/pii/S0166354213001691
http://www.ncbi.nlm.nih.gov/pubmed/23838047?tool=bestpractice.com
A phase 1 trial demonstrated that single and repeated dosing of m102.4 in healthy adults was safe and well tolerated, with no evidence of an immunogenic response.[51]Playford EG, Munro T, Mahler SM, et al. Safety, tolerability, pharmacokinetics, and immunogenicity of a human monoclonal antibody targeting the G glycoprotein of henipaviruses in healthy adults: a first-in-human, randomised, controlled, phase 1 study. Lancet Infect Dis. 2020 Apr;20(4):445-54.
http://www.ncbi.nlm.nih.gov/pubmed/32027842?tool=bestpractice.com
An early phase human clinical trial of m102.4 is ongoing in Queensland, Australia.[52]Vet Practice Magazine. Hendra antibody for humans trialed in QLD. June 2016 [internet publication].
https://vetpracticemag.com.au/hendra-antibody-humans
Chloroquine
Has shown promise in in vitro testing; however, animal studies and limited use in humans (one case of HeV alongside ribavirin) have been disappointing.[34]Broder CC, Xu K, Nikolov DB, et al. A treatment for and vaccine against the deadly Hendra and Nipah viruses. Antiviral Res. 2013 Oct;100(1):8-13.
http://www.sciencedirect.com/science/article/pii/S0166354213001691
http://www.ncbi.nlm.nih.gov/pubmed/23838047?tool=bestpractice.com
Antithrombotic drugs
Aspirin and pentoxifylline have been used in some patients with NiV on the basis that arterial thrombosis may be a contributing factor; however, they were not given in a systematic fashion, making it impossible to assess their efficacy.[22]Goh KJ, Tan CT, Chew NK, et al. Clinical features of Nipah virus encephalitis among pig farmers in Malaysia. N Engl J Med. 2000 Apr 27;342(17):1229-35.
http://www.nejm.org/doi/full/10.1056/NEJM200004273421701
http://www.ncbi.nlm.nih.gov/pubmed/10781618?tool=bestpractice.com
Favipiravir
An investigational antiviral drug that inhibits RNA-dependent RNA polymerase. In one study, favipiravir was effective at preventing NiV infection in a hamster model.[53]Dawes BE, Kalveram B, Ikegami T, et al. Favipiravir (T-705) protects against Nipah virus infection in the hamster model. Sci Rep. 2018 May 15;8(1):7604.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954062
http://www.ncbi.nlm.nih.gov/pubmed/29765101?tool=bestpractice.com
However, there are no studies to confirm its efficacy against NiV or HeV in humans.