Late Relapses of Multibacillary Leprosy
Late Relapses of Multibacillary Leprosy
By Carol A. Kemper, MD, FACP
Dr. Kemper is Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center; Section Editor, Updates; Section Editor, HIV, and Associate Editor for Infectious Disease Alert.
Dr. Kemper does research for GSK Pharmaceuticals, Abbott Laboratories, and Merck. Physician Editor, Stan Deresinski, MD, FACP, Clinical Professor of Medicine, Stanford, Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, serves on the speaker's bureau for Merck, Pfizer, Wyeth, Ortho-McNeil (J&J), Shering-Plough, and Cubist, does research for the National Institutes of Health, and is an advisory board member for Shering-Plough, Ortho-McNeil (J&J), and Cepheid. Peer reviewer Connie T. Price, MD, Assistant Professor, University of Colorado School of Medicine, reports no financial relationships relevant to this field of study.
Source: Fajardo TT, et al. A comparative clinical trial in multibacillary leprosy with long-term relapse rates of four different multidrug regimens. Am J Trop Med Hyg. 2009;812:330-334.
This article originally appeared in the October 2009 issue of Infectious Disease Alert.
These authors followed 189 patients treated in the Phillipines for multibacillary (MB) leprosy with four different regimens, most of whom were followed for at least nine years, and up to 12 years for some. The study included 147 men and 42 women, with a mean age of 28 years at diagnosis (15-60 yrs). To participate in this study, patients were required to have > 2 +AFB on one or more skin smears; most of the patients recruited were either LL or BL on biopsy. Relapses were evaluated by an outside expert not directly involved in the project, and viability of organism was confirmed using mouse footpad inoculation.
Patients were followed for a total of 1,728 patient-years, and an average of 82% of the patients were seen on a regular basis at annual follow-up. Patients were assigned to one of four drug regimens (see Table), and the first month of therapy was directly observed.
Nine years following initiation of therapy, relapse occurred in one of 57 patients (1.87%) receiving regimen A (at year six), one of 55 patients (1.87%) receiving regimen B (at year seven), and no relapses occurred in patients receiving regimen 4. (Another late relapse occurred at year nine in a patient randomized to regimen B, but was lost to follow-up after one month.)
In contrast, seven of 64 patients receiving short-course therapy in regimen C relapsed, all within five to seven years. The overall relapse rate at nine years (11%) and at 12 years (25%) for patients receiving the short-course therapy was significantly greater than patients treated with any of the other WHO-based regimens. Two-thirds of the patients who relapsed had high bacteriologic loads with > 4 +AFB skin smears at baseline. (The authors presumed that all patients with recurrent infection had relapsed, although they acknowledged that re-infection was possible).
Relapses generally remained sensitive to therapy, and none of the isolates were multi-drug resistant. The patient who had been lost to follow-up proved to have a rifampin-resistant organism upon representation; one patient's isolate developed resistance to clofazimine and one had low-level resistance to dapsone.
Remarkably, despite the impressive length of follow-up, only 0%-3% of patients appear at risk for relapse following receipt of a WHO-based, longer-term, MDT regimen. Relapses occurred much later than anticipated, and generally occurred at least six to seven years after initiation of treatment. Even patients who received short-course chemotherapy, who were at greater risk for failure, relapsed at least five to nine years after their initial treatment. Long-term follow-up, for up to 9-12 years, with annual exams and screening smears for patients with MB leprosy is important.
These authors followed 189 patients treated in the Phillipines for multibacillary (MB) leprosy with four different regimens, most of whom were followed for at least nine years, and up to 12 years for some.Subscribe Now for Access
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