Otsuka Pharmaceutical, Co. Ltd. And our U.S.-based subsidiary Otsuka Pharmaceutical Development & Commercialization, Inc., announce that interim data from a Phase 2b/c trial exploring quabodepistat (QBS), in combination with delamanid and bedaquiline, for the treatment of pulmonary tuberculosis (TB) is positive and may shorten the duration of TB treatment for patients. QBS is an investigational anti-tuberculosis compound which has a new mechanism of action that interferes with the cell-wall structure of the bacteria causing TB.^1,2 Worldwide, TB is the second leading infectious fatal disease after COVID-19.

The interim analysis -- which was presented at the 2024 Conference on Retroviruses and Opportunistic Infections in Denver, Colorado in early March -- demonstrated that a four-month regimen of QBS, in combination with delamanid and bedaquiline, can achieve similar safety and efficacy, compared to the six-month, standard-of-care four-drug regimen in participants with drug-susceptible TB.³

These results show that sputum culture conversion rates -- or effectiveness of the treatment combination in killing the bacteria -- at the end of treatment in the pooled QBS-based, three-drug regimen arms were on par with existing standard four-drug TB treatment. The three-drug QBS-based arms were well-tolerated, with no serious treatment emergent adverse events reported, related to the regimens.³

The ongoing study, supported by Otsuka and the Bill & Melinda Gates Foundation, is being held across six clinical research sites in South Africa. Otsuka and the foundation have been collaborating to end TB worldwide, and the foundation contributed to initial funding for the early development of quabodepistat.^2,3

"Otsuka is encouraged by these positive interim data and is pleased to continue working with the support of the Bill & Melinda Gates Foundation to identify safe and effective treatment options for patients living with tuberculosis," said Masanori Kawasaki, global project leader of TB Project at Otsuka Pharmaceutical. "We are deeply thankful to the patients, their families and the clinicians who participated in this important clinical research study."

The trial (NCT05221502) was a multicenter, Phase 2b/c, open-label, randomized, dose-finding trial designed to evaluate the safety and efficacy of a four-month regimen of OPC-167832 (quabodepistat) in combination with delamanid and bedaquiline in patients with drug-susceptible pulmonary tuberculosis in comparison with six months standard treatment. Full results of this phase 2b/c, randomized trial are expected by the end of 2024.^2,3

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