A disease that was once very difficult to cure may now have a more manageable treatment plan.
The Duke Medical Center and the Durham Veterans Affairs Medical Center recently participated in a pulmonary tuberculosis treatment study performed at 23 clinical research facilities nationwide. Researchers tested a new tuberculosis regimen with an experimental drug, rifapentine. It remains in the body longer than previously used drugs, suggesting a possible once-a-week treatment for tuberculosis.
"Current treatment for patients with pulmonary tuberculosis consists of a six-month course of multiple medications," said Dr. Jason Stout, a member of Duke's infectious diseases department.
Most patients are treated with four different medications at first: isoniazid, rifampin, pyrazinamide and ethambutol. For the last two months of treatment, therapy is given every day for two weeks, then twice a week for the remaining five and a half months, Stout said.
All patients in the study received isoniazid, rifampin, pyrazinamide and either ethambutol or streptomycin during the first two months of treatment, which the researchers called the intensive phase. Patients were then either enrolled in a control group or an experimental group. The experimental group received a regimen of once-weekly rifapentine and isoniazid, while the control group received the standard twice-weekly regimen of rifampin and isoniazid.
Researchers found that the patients given the once-weekly treatment regimen showed slightly higher relapse rates on average, but the once-weekly treatment was still considered safe and effective.
"The rifapentine-based regimen is important because the medications can be given once a week after the first two months instead of twice a week with the 'old' treatment regimen," Stout said. "This is more convenient for patients and public health workers, and may reduce the workload borne by our already overburdened public health infrastructure."
Although the current treatment is only applicable to patients who do not show signs of advanced tuberculosis, researchers have initially included people in the study regardless of stage of disease.
"In analyzing the data, people with very severe disease relapsed more often... they don't do well with just once weekly therapy," said Dr. Carol Dukes-Hamilton, who is also a member of the infectious diseases department and key contributor to the research. "[In fact], people who failed to respond well to treatment tended to be people with advanced disease."
In the near future, the study results may be applicable to people with advanced stages of the disease. "Instead of six months of therapy we might add on an additional two months of therapy for people with advanced TB," Dukes-Hamilton said.
This particular study is finished, but several other research projects on tuberculosis are ongoing and some are expanding beyond treatment to prevention.
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