Broadly Neutralizing Antibodies (bnAbs)
Two large trials are investigating bnAbs called VRC01
as a medication for HIV prevention. It could be impractical, however, because VRC01 would have to be given intravenously. Combinations of other antibodies show potential for 6-month duration and administration by subcutaneous injection, according to the editorial.
Biodegradable and Refillable Implants
Long-acting AVRs could have a duration of up to a year in an implant, but Dr. Barnhart questioned how practical it would be to require annual removal and replacement of the implant. He instead proposed biodegradable
or refillable implants, which would require new implant designs.
Implants under development release AVRs through a membrane so that the reservoir gradually empties after the outer coating biodegrades and consequently avoids the potential problem of the device dumping medication when it wears out. A refillable implant has been conceived using refillable nanochannels that would release more than one type of AVR at potentially high doses, the editorial said.
Improved Injection Techniques
Easier-to-use subcutaneous injection devices that allow self-administration or administration by low-level community health workers have already been developed for use with other drugs. Another option would be micro-needle patches—these could be used with new drugs that only need low doses and volumes that could be used quarterly. Their implementation hinges on the ability to manage the cost of manufacturing the injection devices.
Dr. Barnhart stressed that cost is a major consideration when designing treatments for use in middle-to-low income countries. In the past, there have been large gaps between the time new ARV agents were introduced in affluent countries and when they became available in low- and middle-income nations.
To narrow that gap, requirements for products in resource-limited settings may need to be more stringent, according to Dr. Barnhart. For example, the cost of manufacturing, safety during pregnancy, and compatibility with tuberculosis medications need to be considered before new drugs and treatment systems can be useful in the less affluent nations.
“If the current promise is fulfilled, long-acting AVRs can be the keystone in finally controlling the HIV epidemic, and many of the technological and scientific advances made in the process will have application to combating other global healthy scourges, multiplying the long-term impact of these efforts,” Dr. Barnhart concluded.
Disclosure: Dr. Barnhart stated that the opinions expressed in the editorial are his own and not those of USAID.
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