Combined wisdom

By C.H. | NEW YORK

THE International AIDS Conference this week brought a flurry of attention to the scourge. There was the usual talk about the state of the HIV epidemic and unusual excitement about new ways to prevent the disease (see this week’s issue). Buried in the HIV frenzy, however, was a rather important announcement for another blight, tuberculosis.

In the rich world TB conjures images of an ailing John Keats or Emily Brontë. In poor countries it remains a very real problem. It claimed 1.4m lives in 2010. It is the leading killer of those infected with HIV. There are many challenges in fighting TB, but two are particularly thorny. First is the threat of drug-resistant bugs. The number of cases of TB resistant to multiple drugs jumped from 29,000 in 2008 to 53,000 in 2010—and those were just the cases that were officially reported. Second, a common component of TB treatment, rifampicin, interferes with many of the most popular antiretrovirals for HIV.

However, a study published in the Lancet and presented this week offers hope for a new generation of treatment. Andreas Diacon of Cape Town’s Stellenbosch University studied combinations of drugs in infected patients over 14 days. Dr Diacon and his colleagues found that a combination of one experimental drug, one drug approved for other infectious diseases and one existing TB drug had a comparable effect to standard TB treatment.

Importantly, the novel agents mean that the combination may fight some TB strains resistant to other drugs—and do so quite quickly. The drug killed over 99% of patients’ bacteria within the two weeks. Dr Diacon says that using the combination for both drug-susceptible and drug-resistant TB could simplify treatment regimens. He and his colleagues have begun enrolling subjects in Brazil, South Africa and Tanzania to study the combination over eight weeks.

There are two other important implications. First, Dr Diacon showed a new way to test TB drugs. Rather than wait for years as individual drugs trudge through clinical trials, then test them in combination, scientists can quickly explore whether certain combinations are worth considering. This has a hitch. “If there is a side effect,” says Dr Diacon, “we won’t always be able to know which drug causes it.” But testing combinations quickly has clear merits. Second, the treatment does not contain rifampicin, so should work with most antiretrovirals.