Dr. Ganapati, et al. reply
To the Editor:
We note with concern the high rate of leprosy relapse after treatment with the promising combination of rifampin and ofloxacin (RO), as reported by Ji. el al. (abstract in March 1998 UL). While recording in the same issue of the Journal our experience with a solitary case in a large sample of patients in western India, we were unaware of the documentation of similar events in Africa by a keen group of workers in late 1997 in the journal Antimicrobial Agents Chemotherapy, to which we have no access. We deeply appreciate the prompt publication by the authors and the quick abstracting by your Journal.
However, we cannot help but point out some sharp differences between the African and Indian samples studied. All of the five relapsed cases observed in the trial by Ji, el al. had received dapsone monotherapy before RO treatment; whereas all of our cases were untreated prior to inclusion in the trial. The significance, if any. of the possible influence of prior treatment (1) with dapsone is not clear and demands further scrutiny. We have earlier drawn attention to the late relapses after WHO/MDT occurring in excessively treated patients, especially with dapsone. This is in line with statements found in the literature (2). Another feature of the relapse after RO reported by us is the response to re-treatment with RO, indicating the possibility of "persisters" as the cause of relapse. This patient is under continuous observation for further events, if any. We also have to point out in this connection that we have already reported (under publication) on a patient who, in spite of the laboratory evidence of resistance to dapsone, rifampin and ofloxacin, has responded very well over a follow-up period of 6 years to the treatment regimen of 24 months of WHO MB-MDT, with ofloxacin daily for 28 days initially.
As regards the rates of relapse, in our sample of 98 patients after 360 patient-years of follow up, one relapse has been encountered, giving an overall relapse rate of 1.02% (95% CI l.01%-3.05%) or 0.28 relapses (95% CI 0.28-0.84) per 100 patient-years. These rates are not alarmingly high considering the fact that 30 patients (30.6%) of the total cases have been followed up for more than 5 years; whereas a 10% relapse rate from Africa seems unacceptable. We hope to report on a detailed analysis of relapse rates in the total sample in due course. We, however, wonder at this stage whether there is an ethnic variation determining the occurrence of relapses in general, irrespective of the treatment regimen offered.
- Dr. R. Ganapati
Dr. V. V. Pai
Dr. C. R. Revankar
Dr. H. O. Bulchand
S. Kingsley
Kailas Gandewar
Bombay Leprosy Project
11 V.N. Purav Marg
Sion-Chunabhatti
Mumbai 400 022, India
REFERENCES
1. CHATTERJEE, B. R. Leprosy: Etiobiology of Manifestations, Treatment and Control. 1st edn. Jhalda, India: Leprosy Field Research Unit. 1993 , pp. 348-355.
2. SHEN , J. Regarding relapse alter long-term follow up of multibaeillary patients treated by WHO multidrug regimen. Int. J. Lepr. 64 (1996) 79-80.