GENEVA (Reuters) -Global health aid agency Unitaid has written to Johnson & Johnson's CEO, Joaquin Duato, urging "immediate action" to expand access to the company's tuberculosis drug bedaquiline, which is protected by patents hindering generic alternatives.

While J&J has lowered the price of bedaquiline, which is used to treat drug-resistant tuberculosis (DR-TB), Unitaid said it was an "incomplete solution" and countries like South Africa, Belarus and Ukraine were not benefiting.

"Today Johnson & Johnson continues to enforce secondary patents in many of the countries with the highest burden of DR-TB, hindering generic manufacturer competition and impeding broader access to this critical medicine," said the letter, signed by Unitaid's executive director Philippe Duneton.

The agency is urging J&J to remove all secondary patents and ensure that lower prices are available to all countries with high TB cases.

J&J confirmed its intent not to enforce patents for bedaquiline in a statement on Friday, assuring current and future manufacturers that it will not allege them of infringing the drug's patents, provided the "generic versions of SIRTURO produced or supplied by generic manufacturers are of good quality, medically acceptable, and are used only in the 134 low- and middle-income countries."

A Unitaid spokesperson said it was unusual for the agency to publish its communications with the heads of pharmaceutical companies and it had done so because of the importance of the issue.

Earlier this month there was a high-level meeting on TB at the UN General Assembly, and advocates hope for more of a focus on the disease and better access to treatments.

TB, a bacterial disease that mostly affects the lungs, is preventable and treatable, but 10 million people catch it annually. Around 1.6 million people died from TB in 2021, almost entirely in low- and middle-income countries, according to the World Health Organization (WHO).

Multi-drug-resistant TB - a form of the disease that doesn't respond to the standard drugs - is described by WHO as a "public health crisis", with only one in three people who needed treatment in 2021 managing to access it.

(Reporting by Emma Farge; Additional reporting by Jennifer Rigby and Devika Nair; Editing by Susan Fenton, Elaine Hardcastle and Leslie Adler)