COPENHAGEN (November 19, 2025)—New clinical trial results presented by TB Alliance at the Union World Conference on Lung Health show that the novel antibiotic candidate sorfequiline (TBAJ-876), a next-generation diarylquinoline, has the potential to improve tuberculosis (TB) treatment when combined with pretomanid and linezolid in a treatment regimen known as "SPaL."
The NC-009 trial (a pan-Phase 2 clinical trial) showed that, overall, sorfequiline had greater activity than bedaquiline. The 100 mg SPaL regimen had greater activity against TB than the standard of care HRZE (isoniazid, rifampin, pyrazinamide, and ethambutol), indicating the potential to shorten treatment time for active TB. In addition, the SPaL regimen had a comparable safety profile to the standard of care for people with drug-sensitive TB (DS-TB).
TB Alliance conducted the trial in 22 sites in South Africa, the Philippines, Georgia, the United Republic of Tanzania, and Uganda.
"Science continues to surge forward, to the benefit of health care systems, people with TB, their families, and their communities," said Dr. Mel Spigelman, President and CEO of TB Alliance. "The development of the BPaL regimen allowed us to reduce treatment time for most drug-resistant TB to six months, a critical development for patients. Now, we have an opportunity to shorten treatment even further — representing an important milestone toward our goal of developing an ultra-short regimen capable of treating both drug-sensitive and drug-resistant TB."
Sorfequiline and bedaquiline both belong to the diarylquinoline class of antibiotics, which target a key enzyme of the tuberculosis bacteria involved in energy production. In 2012, bedaquiline was approved for drug-resistant TB treatment, making it the first new antibiotic to be approved in decades. However, recent years have seen a rise in strains of TB that are resistant to bedaquiline.
TB Alliance has been developing sorfequiline all the way through the R&D process, from early discovery to, now, late-stage clinical trials. Trial results show that sorfequiline could have a potentially a better safety profile than bedaquiline along with the potential to treat many of the strains that are resistant to bedaquiline.
"The research pipelines addressing a neglected disease like TB continue to deliver the promise of shorter and safer treatment for the millions affected around the world," said Dr. Rod Dawson, Principal Investigator for NC-009 and Managing Director & Clinical Research Unit Head at the University of Cape Town Lung Institute. "Goals that once seemed wholly aspirational, like the eradication of TB, are made increasingly possible because of advancements like sorfequiline and, before that, pretomanid. But we have a lot of work ahead of us and cannot stop until TB is no longer a threat."
TB Alliance is strengthening partnerships with high-burden countries like India, China, Indonesia, South Africa and Brazil in advance of launching a Phase 3 clinical trial in 2026. This upcoming trial is an opportunity to earn approval for a new drug and regimen, as well as the first step in the process of developing an ultra-short regimen. These partnerships build from the work performed in the development and roll out of BPaL-based regimens, and they seek to further streamline the process of developing new TB treatments and accelerate the pace at which those impacted by TB can access improved treatments.
"The treatment was amazing. It was shorter and easier than I expected," said Thuto Pulane, a participant in the NC-009 clinical trial. "I'd tell anyone not to be afraid. TB treatment has come a long way, and this new research gives us even more hope."
Sorfequiline has been developed in pill form, and SPaL will also be an all-oral TB treatment. In addition to the upcoming SPaL Phase 3 trial, TB Alliance plans to explore delivering a sorfequiline-based regimen as a long-acting injectable (LAI), a formulation that could potentially help reduce treatment duration to as little as one month.
"For decades, the standard treatment time for tuberculosis has been six months," said Dr. Maria Beumont, Vice President and Chief Medical Officer at TB Alliance. "With BPaL, we proved that we can dramatically simplify and shorten drug-resistant TB treatment, but that was just the first step. With regimens currently in development, we believe we can shorten and simplify treatment even further — for all forms of TB. The results from this trial bring us closer to our goal and the eventual eradication of TB as a global health threat."
Background
TB is a difficult infection to cure, requiring patients to take a combination of medicines for at least four to six months. Even after symptoms disappear, medicines still need to be taken so that all traces of the disease can be fully eradicated. The scope and intensity of TB globally is in large part fueled by antiquated and inadequate TB drugs. Novel drug regimens are urgently needed to bring the TB pandemic under control.
The BPaL regimen — which combines the antibiotics bedaquiline (B), pretomanid (Pa), and linezolid (L) — was first clinically studied by TB Alliance. Pretomanid, as part of the BPaL regimen, received its first regulatory approval in August 2019 for use against highly drug-resistant strains of TB. This marked the first-ever regulatory approval of a TB drug developed by a non-profit. Previously, fewer than two-thirds of drug-resistant TB patients around the world had been successfully treated. Treatment options were limited, expensive, toxic, and lengthy — requiring patients to take more than 20 pills per day for 9 months to two years or longer. Since approval, more than 210,000 courses of pretomanid have been ordered globally, leading to an estimated 11,000 lives and $100 million USD saved globally .
In past in vitro studies, sorfequiline demonstrated anti-mycobacterial activity approximately 10-fold greater than bedaquiline and, in preclinical studies, sorfequiline showed the potential to be safer than bedaquiline, including low potential for QT prolongation. In Phase 1 studies involving 165 healthy subjects, few, generally mild, adverse events were observed.
