CDC Recommends New Regimen for Latent M
tuberculosis
Laurie Barclay, MD
December 10, 2011 — The US Centers for Disease Control and
Prevention (CDC) recommends a new isoniazid-rifapentine
(INH-RPT) regimen with direct observation to treat latent Mycobacterium tuberculosis infection (LTBI),
according to a report published in the December 9 issue of the Morbidity
and Mortality Weekly Report. This new treatment regimen should considerably
shorten and simplify treatment.
"TB develops in 5%–10% of persons who get infected
with M. tuberculosis, typically after a latency of 6–18 months, but
after decades in some persons," write John A. Jereb, MD, and
colleagues from the Division of Tuberculosis Elimination, National Center for
HIV, Viral Hepatitis, STD, and TB Prevention.
"Conditions that impair cellular immunity, especially
HIV infection, increase the likelihood of TB developing at any interval after
infection. Treatment during latency prevents TB during treatment and afterward."
Until now, the standard regimen for treatment of LTBI in the
United States has been 9 months of INH daily without directly observed therapy
(DOT). However, a new combination
regimen of INH-RPT given weekly for 12 weeks as DOT is as effective as other
regimens for TB prevention and is more likely to be completed,
according to findings from 3 randomized controlled trials and expert opinion.
Instead of 270 daily doses of INH, the new regimen substitutes 12 once-weekly doses of INH and RPT.
Directly observed therapy under the supervision of a healthcare worker ensures
adherence to the regimen and facilitates safety monitoring.
The CDC recommends monitoring for adverse effects of the
new INH-RPT regimen, even though it was well-tolerated in treatment trials.
Severe adverse effects should be reported to the US Food and Drug
Administration and the CDC.
"Treating for
LTBI when TB is active could result in partial treatment and drug
resistance," the authors write. "Some patients who have radiographic
findings of presumed old 'healed' TB might have active TB, and they should be
examined for it before treating LTBI. A 4-drug
regimen may be started while mycobacterial culture results are pending."
HIV-infected patients are also more likely than patients
without HIV infection to have extrapulmonary TB or pulmonary TB with normal
chest radiography.
Patients for Whom INH-RPT Is Recommended
For otherwise healthy persons aged 12 years or older who
have LTBI and factors predicting development of TB, the new regimen is recommended
as an option comparable to the 9-month INH regimen. These predictive factors
include recent exposure to contagious TB, conversion from negative to
positive on an indirect test for infection, and radiographic findings of healed
pulmonary TB.
The new regimen is also recommended for HIV-infected
patients who are otherwise healthy and are not taking antiretroviral
medications.
The new regimen may offer practical advantages to other
patient subgroups and can be considered in these settings, such as correctional
settings, clinics for recent immigrants, and homeless shelters. Weekly
INH-RPT can also be considered for individual patients who are unlikely to
complete 9 months of daily INH.
Patients for Whom INH-RPT Is Not Recommended
Earlier LTBI regimens are still recommended as the standard
of care for some patients, and recommendations for using the previous regimens
for treating LTBI remain unchanged.
Factors affecting the choice between INH and INH-RPT include
feasibility of DOT, availability of the drugs, patient monitoring and other
program operations, likelihood of treatment completion based on medical and
social patient circumstances, and patient and prescribing physician
preferences.
Patients with comorbid illnesses that are associated with
TB, such as diabetes mellitus, or that might reduce INH-RPT tolerability should
be considered on a case-by-case basis.
Children aged 2 to 11 years should receive 9 months of daily
INH. On a case-by-case basis, however,
INH-RPT can be considered when completion of 9 months of daily INH is unlikely
and the risk for TB is great.
INH-RPT should not be used in children younger than 2 years,
in HIV-infected patients receiving antiretroviral treatment, in women who are
pregnant or who are expecting to become pregnant during treatment, and in
patients with LTBI presumed to be resistant to INH or RIF.
Morb Mortal Wkly Rep.
2011;60:1650-1653. Full text
Medscape Medical News
© 2011 WebMD, LLC
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