On Wednesday morning, Janie Louie, MD, MPh, medical director, San Francisco Department of Public Health, Oakland, California, presented a session during the Tuberculosis (TB) track titled Real-World Application of Short-Course Treatment Regimens.

Dr. Louie said that shorter treatment courses are needed for a variety of reasons, including greater nonadherence and adverse events associated with longer regimens. She added that long-duration TB treatment regimens are more resource intensive due to symptom and laboratory monitoring, clinical visits, and Directly Observed Therapy. “It can also be uncomfortable, inconvenient, and stressful for patients,” she said.

The ideal new regimen, in contrast, is potent/bactericidal, well tolerated, has a low pill burden, once daily, inexpensive, and is already used in other infections with good safety data at established doses, she said.

Dr. Louie pointed to the S31/A5349 study (Study 31) finding that 17-week TB regimens of isoniazid, rifapentine, moxifloxacin, and pyrazinamide (HPMZ) were noninferior to a 26-week regimen. The protocol for an HPMZ pilot in San Francisco, she said, was 8 weeks of INH 300 mg qd, rifapentine 1,200 mg qd administered within 1 hour of food), moxifloxacin 400 mg qd (moxifloxacin is preferred but can also use levofloxacin), PZA (weight based). This is followed, she said, by 9 weeks of INH 300 mg qd, rifapentine 1,200 mg qd, and moxifloxacin 400 mg qd (or levofloxacin).

Detailing management strategies in HPMZ-treated patients, Dr. Louie said that if a patient cannot tolerate therapy, clinicians should stop and rechallenge with the standard treatment regimen. She added that in there is concern for treatment failure, such as radiographic improvement is slowing or smear and cultures do not show improvement by 8 to 12 weeks, clinicians should consider extending HPMZ to 6 months or longer if needed or switch to the standard regimen.

“TBTC Study 31 proved the concept, and further U.S. studies are needed on who are the best candidates to benefit from HPMZ,” she concluded. Dr. Louie added that more U.S. focus is needed on maintaining sustainable drug supplies, reducing drug costs, managing adverse events, and making available rapid molecular testing for resistance.

“The main benefit of HPMZ may be reduced treatment duration of high burden/cavitary disease from 9 months to 4 months,” she added.