An unfortunate result of nevirapine administration is the development of HIV resistance mutations to non-nucleoside reverse transcriptase inhibitors (NNRTIs). Selected within weeks of administration, these resistance mutations have been associated with a decrease in the efficacy of future NNRTI based treatments when women resume therapy for their own health needs.

The PHPT-4 has proven it possible to reduce the risk of developing of NNRTI resistance mutations from 20.7 percent to only 1.8 percent by administering zidovudine (ZDV) plus didanosine(ddI) to the mother for one month after delivery. The regimen is safe and well tolerated and furthmore, the drugs do not interfere with HBV replication, which affects approximately 10 percent of the south east Asian population. Using this treament, women can benefit from nevirapine for protection of their child without compromising their future treatment options.

A sensitive assay capable of detecting very small presences of resistance mutations present in more than five percent of the viral population called an Oligonucleotide Ligation Assay (OLA) was used to detect resistance mutations in the subjects at 12, 42 and 120 days postpartum.

For further information please refer to One Month Dual Antiretroviral Prophylaxis to Prevent Resistance Mutations in Mothers Exposed to Single Dose Nevirapine [clinicaltrials.gov]