Cecile Magis-Escurra, respiratory disease specialist at the University Centre for Chronic Diseases Dekkerswald, co-authored a publication in the New England Journal of Medicine.
The Tuberculosis Network Clinical Trialsgroup (TBNET), an international consortium of clinicians and scientists, has proposed new treatment outcome definitions for multidrug resistant tubercolosis (MDR-TB). TBNET documented the management of patients with MDR-TB at 23 different sites across Europe where they found that treatment outcomes according to the definitions proposed by the WHO did not correlate to sustained culture conversion and being free of relapse in the absence of therapy. Applying the novel TBNET MDR-TB outcome criteria “cure” is reached twice as often as compared to the WHO criteria in their study.
The number of patients with MDR-TB has dramatically increased worldwide over the past decade. The largest number of patients who have been identified with MDR-TB lives in the WHO region Europe. Chances for “cure” for these patients were thought to be small. In the latest report of the European Centre for Diseases Prevention and Control (ECDC) and the WHO Regional office for Europe, “treatment success” from MDR-TB was less than 50 %. The definition of “treatment success” by the WHO includes patients who are “cured” (having three negative sputum cultures taken at least 30 days apart during the continuation phase of treatment) but also patients who simply “complete the treatment” without failure. An observational follow-up period, to identify disease recurrence in the absence of therapy is not included in the WHO criteria for MDR-TB treatment outcome presently.
International cohort with 380 patients
As part of the EU Commission funded TB-PANNET project 380 patients with MDR-TB were observed at 23 TBNET centers in countries of high, intermediate and low incidence of TB in Europe over a period of 5 years. Observation started from the time of diagnosis and lasted until one year after the end of the treatment. The researchers found that the WHO criterion for “cure” could not be applied in the majority of patients, simply because most patients who were being treated successfully were not able to produce sputum after 8 months of therapy.
TBNET proposed new definitions for “cure” and “failure” of MDR-TB treatment based on the sputum culture status at 6 month after the initiation of therapy and whe
ther patients were free from disease recurrence one year after the end of therapy. “No-one would call a patient with cancer to be cured at the end of chemotherapy. Patients with MDR-TB also need to be closely monitored after the end of treatment to identify patients who experience disease recurrence”, states a TBNET scientists.
In their study the results for “cure” from MDR-TB correlate very well with the level of drug resistance and the time to culture conversion. The new definitions are also independent of the total duration of treatment and can be applied to the standard 20 months MDR-TB regimen as well as to the 9-12 months shorter course MDR-TB treatment that was recently proposed by the WHO.
Cure-rates from MDR-TB were 61% in this study, compared to only 31% when using the WHO criteria.
Hope, but still a lot to be done
Results from the TBNET study are encouraging. “There is still a lot to do to improve treatment outcomes in MDR-TB as 1/3 of affected patients still cannot be cured in Europe. The prognosis may be worse in other parts of the world. We are optimistic that outcomes can be improved with novel medicines and individually tailored treatment managements, rather than programmatic fixed combinations of drug-regimens and a one-for-all duration of therapy” says a TBNET spokesman.
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