Approval for drug that makes TB cure simpler

Pretamonid, a novel compound developed by the non-profit organization TB Alliance, was approved by the US Food & Drug Administration (FDA) on August 14.

The US drug regulator has approved a new medicine for treating deadly, drug-resistant forms of tuberculosis (TB) that makes the treatment regimen shorter and simpler.

There are more than half a million cases of multi drug-resistant TB (MDR-TB) annually, with about 6% of those cases being extensively drug-resistant TB (XDR-TB) cases. (Shutterstock/Representative Image)

Pretomanid, a novel compound developed by the non-profit organization TB Alliance, was approved by the US Food & Drug Administration (FDA) on August 14.

TB is the leading infectious cause of death worldwide, killing at least 1.6 million people annually.

There are more than half a million cases of multi drug-resistant TB (MDR-TB) annually, with about 6% of those cases being extensively drug-resistant TB (XDR-TB) cases. India accounts for nearly a quarter of the global TB cases.

The new drug was approved under the Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD pathway) as part of a three-drug, six-month, all-oral regimen for the treatment of people with XDR-TB or MDR-TB, who are treatment-intolerant or non-responsive.

The LPAD pathway was established by the US drug regulator as a tool to encourage further development of antibacterial and antifungal drugs to treat serious, life-threatening infections that affect a limited population of patients with unmet needs.

“The associated novel regimen will hopefully provide a shorter, more easily manageable and highly efficacious treatment for those in need,” he added.

The three-drug regimen consisting of bedaquiline, pretomanid and linezolid – collectively referred to as the BPaL regimen – was studied in the pivotal Nix-TB trial across three sites in South Africa. The trial enrolled 109 people with XDR-TB and also MDR-TB.

Nix-TB data demonstrated a successful outcome in 95 of the first 107 patients after six months of treatment with BPaL and six months of post-treatment follow-up. For two patients, treatment was extended to nine months.

TB, in all forms, is treated with a combination of drugs; the most drug-sensitive forms of TB require six months of treatment using four anti-TB drugs.

Treatment of XDR-TB or MDR-TB takes longer and is more expensive, with patients currently taking a combination of as many as eight antibiotics, some involving daily injections, for 18 months or longer.

“Until very recently, people infected with highly drug-resistant TB had poor treatment options and a poor prognosis,” said Dr Francesca Conradie, principal investigator of the Nix-TB trial.

“This new regimen provides hope with 9 out of 10 patients achieving culture negative status at 6 months post-treatment with this short, all-oral regimen.”

The drug is likely to be available in the US markets by the end of 2019.

TB activists want the drug to be made affordable so that poor patients could also access it.

“As the third new drug developed for TB in over half a century, and the first to be developed as part of a ready-to-use treatment regimen, pretomanid’s approval represents another potent tool for tackling difficult-to-treat drug-resistant forms of TB,” said Médecins Sans Frontières (MSF), in a statement.

“However, it must be made affordable to everyone who needs it, especially considering the substantial taxpayer and philanthropic contributions that went into its development,” it added.

With its high burden, India should consider all options for shorter and safer drug regimens, say experts.

“It’s important for India to conduct trials with all new and repurposed drugs, and figure out the best short regimen for the Indian context. Right now trials are mired in bureaucratic delays and Indian patients are likely to miss out on really good options,” says Dr Madhu Pai, director, McGill International TB Centre.