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Otsuka Announces Interim Data from Phase 2b/c Trial Indicating New Investigational Compound May Shorten Tuberculosis Treatment – MedNews

Princeton, N.J. and Tokyo, Japan – March 21, 2024 – Otsuka Pharmaceutical Development & Commercialization, Inc., and our parent company Otsuka Pharmaceutical, Co. Ltd., 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. “We are deeply thankful to the patients, their families and the clinicians who participated in this important clinical research study.”

“Over the past 50 years, Otsuka has emerged as a leader in tuberculosis treatment, striving to find treatment options for both adults and children affected by the disease,” said John Kraus, M.D., Ph.D., executive vice president and chief medical officer at Otsuka. “We believe quabodepistat represents the next chapter of Otsuka’s ongoing commitment.”

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

About Otsuka

Otsuka Pharmaceutical Co., Ltd. is a global healthcare company with the corporate philosophy: Otsuka–people creating new products for better health worldwide. Otsuka researches, develops, manufactures, and markets innovative products, with a focus on pharmaceutical products to meet unmet medical needs and nutraceutical products for the maintenance of everyday health.

In pharmaceuticals, Otsuka is a leader in the challenging areas of mental, renal, and cardiovascular health and has additional research programs in oncology and on several under-addressed diseases including tuberculosis, a significant global public health issue. These commitments illustrate how Otsuka is a “big venture” company at heart, applying a youthful spirit of creativity in everything it does.

Otsuka established a presence in the U.S. in 1973 and today its U.S. affiliates include Otsuka Pharmaceutical Development & Commercialization, Inc. (OPDC) and Otsuka America Pharmaceutical, Inc. (OAPI). These two companies’ 2,000 employees in the U.S. develop and commercialize medicines in the areas of mental health and nephrology, using cutting-edge technology to address unmet healthcare needs.

OPDC and OAPI are indirect subsidiaries of Otsuka Pharmaceutical Company, Ltd., which is a subsidiary of Otsuka Holdings Co., Ltd. headquartered in Tokyo, Japan. The Otsuka group of companies employed 47,000 people worldwide and had consolidated sales of approximately USD 14.2 billion in 2023.

All Otsuka stories start by taking the road less traveled. Learn more about Otsuka in the U.S. at and connect with us on LinkedIn and Twitter at @OtsukaUS. Otsuka Pharmaceutical Co., Ltd.’s global website is accessible at


  1. Hariguchi N et al. OPC-167832, a Novel Carbostyril Derivative with Potent Antituberculosis Activity as a DprE1 Inhibitor. Antimicrob Agents Chemother. 2020 May 21;64(6):e02020-19.
  1. Dawson R et al. Quabodepistat in Combination with Delamanid and Bedaquiline in Participants with Drug-Susceptible Pulmonary Tuberculosis: protocol for a multicenter, phase 2 b/c, open-label, randomized, dose-finding trial to evaluate safety and efficacy. Trials. 2024 Jan 19;25(1):70.
  1. Dawson R et al. A 4-month Regimen of Quabodepistat, Delamanid and Bedaquiline for Pulmonary TB: Interim Results. Conference on Retroviruses and Opportunistic Infections (CROI), 5 March 2024, Denver, Co., USA; Abstract no. 163.

Source: Otsuka Pharmaceutical, Co. Ltd.

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