2009 was not a banner year for HIV drug development, yet over a dozen drugs are in Phase II and III clinical studies. These drugs will be incremental advances, but not exceptional enough to change the current paradigm. Some of these are "me-too" agents from existing drug classes, but there are also new drug classes in research.
It is clear that AIDS activism over the last 20 years has pushed the development of several good options for many people, and competition among the drug companies is fierce. The HIV drug market has become saturated with a few good drugs but includes some older average-to-poor drugs, some no longer recommended by the DHHS Guidelines.
There are important reasons for continued development of safer drugs, newer classes and improved dosing. Many people have suboptimal or discordant responses to current regimens, or they cannot tolerate specific drugs. Twice or even once daily regimens could always be improved upon. In a better scenario, drugs that would only have to be taken once a week or month do exist in other diseases, and this strategy is on the AIDS advocacy agenda.
It has been two years since the last drug, Intelence (etravirine), reached FDA approval. Isentress (raltegravir) and Selzentry (maraviroc), drugs from new drug classes, were approved in late 2007. All these drugs represent change we may be looking for in a few ways.
Intelence provides a new NNRTI for a class that has not seen a drug to overcome resistance. It has taken years to reach this point. Isentress has been an important drug in that it is the first integrase inhibitor, but is potent and long lasting when added to another new drug for those who had few treatment options. It was recently approved as a first line drug as well.
However, we know now that there is a growing number of people who develop Isentress resistance and have blown through the integrase class so far. Many have no other options so they find themselves in salvage therapy. Selzentry is limited because it only impacts CCR5 tropic virus, which is not useful for those who may have dual/mixed tropism or CXCR4 tropism.
There are new approaches and a few strategy studies that seek to improve the current drugs. Better tolerability, higher barrier to resistance, and better dosing are all goals being studied and in some cases proving to be effective so far. The latest drugs nearing approval for treatment experienced individuals are:
A new drug nearing approval for treatment naive individuals is: