An investigational HIV drug being developed by Merck may be able to provide extended protection against the infection for up to 1 year through a drug-eluting implant, according to preliminary data presented at the 10th International AIDS Society Conference on HIV Science.
 
Islatravir, formerly known as MK-8591, is a nucleoside reverse transcriptase translocation inhibitor (NRTTI) being evaluated for the treatment of HIV in combination with other antiretrovirals, as well as for pre-exposure prophylaxis (PrEP) as a single agent in both a once-monthly oral 2-drug regimen and in an extended delivery formulation.
 
Notably, the treatment is being developed for extended administration through a prototype subdermal drug-eluting implant for use as PrEP. 
 
The phase 1 implant study evaluated the safety and pharmacokinetics of islatravir administered sub-dermally using a polymer drug-eluting implant approximately the size of a match, which is inserted in the skin of the upper arm of the non-dominant hand. Patients in the study received an implant containing doses of either 62 mg, 54 mg, or a placebo. Implants were removed after 12 weeks and patients were evaluated for another 4 weeks thereafter.
 
After assessing blood levels of the drug, the researchers determined that the implant containing islatravir 62 mg was effective in providing protection for 12 months. Additionally, the findings suggest that control of intracellular concentrations can be managed by varying the islatravir load in the implant, the study authors noted.
 
According to Merck, the data provide early evidence for its potential as a once-yearly option for PrEP in individuals at high risk of HIV.
 
“We are encouraged by the results of this proof of concept study exploring the potential of delivering meaningful doses of islatravir over a 12-week period,” Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories, said in a statement. “At Merck, we recognize multiple options are needed to address the needs of individuals at risk of HIV-1, and we are committed to investigating those options. Through the application of our established expertise in drug delivery, we are seeking to capture the potential of islatravir for HIV-1 pre-exposure prophylaxis.”
 
Merck plans to initiate a phase 2 trial for the once-monthly oral formulation for PrEP, as well.
 
Reference
 
Merck Presents Early Evidence on Extended Delivery of Investigational Anti-HIV-1 Agent Islatravir (MK-8591) via Subdermal Implant [news release]. Merck. https://www.mrknewsroom.com/news-release/research-and-development-news/merck-presents-early-evidence-extended-delivery-investiga. Accessed July 24, 2019.