WASHINGTON – Johnson & Johnson has won accelerated Food and Drug Administration approval for its tuberculosis tablet Sirturo, the first medicine in 40 years that provides a new way to treat the contagious lung infection.

The FDA cleared Sirturo to be added to existing therapies for use by adults whose illness is resistant to multiple drugs, New Brunswick, N.J.-based J&J said Monday in a statement. The FDA cleared Sirturo based on the second of what are typically three clinical trial phases, an option the agency has when a drug treats a serious disease and fills an unmet need.

There were 8.7 million new cases worldwide of tuberculosis in 2011, with multidrug-resistant forms accounting for as many as 400,000 cases, according to a World Health Organization report.

The international charity Doctors Without Borders called approval of Sirturo “an immense milestone,” and FDA Commissioner Margaret Hamburg said the drug adds a new weapon “to the arsenal for fighting this deadly, contagious disease.”

“The fact that the drug is active against drug-resistant forms of the disease makes it a potential game changer,” Dr. Manica Balasegaram, executive director of the Doctors Without Borders Access Campaign, said in an emailed statement.

Most drug-resistant cases occur in China, India, the Russian Federation and South Africa, according to the WHO. While tuberculosis was once the leading cause of death in the U.S., the drug-resistant version of the illness affected about 98 people in the nation last year, according to the Centers for Disease Control and Prevention.

Finding a treatment for tuberculosis was the passion of Paul Janssen, founder of JJ unit Janssen Pharmaceutica, whose sister died of the disease, said Paul Stoffels, JJ’s chief science officer and worldwide chairman of its pharmaceuticals group. U.S. approval will help gain clearance in other countries where the disease is more of a burden, he said.

“We’ll be able to treat many more people and get them cured for tuberculosis,” Stoffels said. “In the long run, treatment might get simplified, get shorter.”

J&J sought approval for the drug, known chemically as bedaquiline, based on the second phase of clinical trials. The company, the world’s second-biggest seller of health-care products, plans to start a final-phase trial in the first quarter of 2013 to study bedaquiline use for nine months compared with a placebo, said Chrispin Kambili, global medical affairs leader for bedaquiline.

Typical treatment currently for multidrug-resistant tuberculosis can be as long as two years, Kambili said. The disease is characterized by a long-lasting cough. The study beginning next year will aim to examine 600 patients over five years.

Multidrug-resistant tuberculosis is defined as not responding to the two most popular drugs that are typically first used against the illness: isoniazid and rifampicin, according to the WHO.

Approval from the FDA and European authorities where J&J also has applied for marketing authorization will help the company achieve approval in parts of the world where U.S. and EU opinions serve as references, Stoffels said.

J&J will request a voucher from the FDA that allows a company that gained approval for a drug to treat a neglected disease to seek an expedited review of another treatment. The company hasn’t chosen which medicine it will use the voucher on if it gets one, Stoffels said.

While more patients responded to the treatment regimen when bedaquiline was added to the lineup, more patients who took the medicine in studies also died, Kambili said.

“We were puzzled by this observation,” he said.

In one trial, 10 of 79 bedaquiline-treated patients, died compared with two of 81 who took a placebo, the FDA said in a report.