Four years ago the Feinberg School of Medicine began the first study on the HIV drug Kaletra.
At the time, no one could have predicted Kaletra would become the drug all other HIV drugs would be measured against.
But at a medical conference in San Diego last week, Feinberg Prof. Robert L. Murphy presented an analysis of the school’s study showing that patients still respond to Kaletra after four years.
It marks the first time patients have responded to any protease inhibitor, the type of HIV drug Kaletra is classified as, for this length of time, Murphy said. Protease inhibitors work to prevent the body from duplicating the HIV virus.
“What is unique about Kaletra is that, if it is the first drug taken after finding out one is HIV positive, we have not seen any patients who have developed a resistance to Kaletra,” said Nicole Wesley, manager of pharmaceutical public affairs for Abbott Laboratories in North Chicago.
Kaletra now is the most prescribed protease inhibitor, accounting for 28.6 percent of all sales, Wesley said.
When combined with other drugs, the drug has the ability to lower the amount of HIV in a patient’s blood to undetectable levels, Murphy said.
“It decreases the amount of virus circulating to levels so low that we can’t even measure it,” he said.
Of the 100 people who participated in the study, which began four years ago, 72 still are taking the drug in combination with other HIV drugs. None of the 72 has become resistant to the drug’s effects and all had virtually undetectable levels of the virus, Murphy said.
As the amount of HIV in the blood decreases, there is a lower chance that the patient can transmit the virus to others, including unborn children, Murphy said.
“For women who are pregnant, if they have low levels of the virus, they typically do not transmit it to their babies,” he said.
Kaletra works best in patients who have never taken any HIV medicine, because such patients have not had the chance to build up resistances to other medicines, Wesley said.
Currently, the Food and Drug Administration is reviewing Kaletra for approval.
