Nucleotide Reverse Transcriptase Inhibitors
Tenofovir (TDF): It is an adenosine analogue used in first line regimen in adults. However, data in children is minimal and a study in HIV infected antiretroviral experienced children has demonstrated a decrease in bone mineral density thus potentially limiting its use in pre-pubertal children.

Fusion Inhibitors
These agents inhibit viral binding or fusion to host target cells. T-20 (Enfurvirtide) is the drug currently used and has to be given subcutaneously. It is used as part of salvage regime in patients who have multi-antiretroviral therapy regime failures.

Other new drugs
Two new molecules have now been tried for treatment of multidrug resistant HIV infection. They are TMC-114 (a new protease inhibitor which is a combination of Darunavir/Ritonavir) and TMC-125 ( a new NNRTI). However both these molecules are still research molecules. In the laboratory, TMC-114 has shown to be sensitive to almost all protease inhibitor (PI) mutations. Two pivotal phase III studies, TMC-C206 and TMC-C216 (also known as DUET 1 and DUET 2) have recently been initiated in the USA and will be starting in early 2006 in 17 other countries across the globe. This program comprises two randomized, placebo-controlled trials in treatment-experienced HIV-1 infected adult patients with documented NNRTI resistance and at least 3 primary PI mutations.