GENEVA, Sept 29 (Reuters) - Global health aid agency Unitaid has written to Johnson & Johnson's (J&J) CEO Joaquin Duato, urging him to take "immediate action" to expand access to the company's tuberculosis drug bedaquiline.

While J&J has already lowered the price of bedaquiline which is used to treat drug-resistant tuberculosis (TB), Unitaid said this was an "incomplete solution", saying 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. It urged J&J to remove all secondary patents and ensure that lower prices were available to all countries with high TB cases.

A Unitaid spokesperson said it was unusual for the aid agency to directly contact the heads of pharmaceutical companies.

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. (Reporting by Emma Farge; Editing by Susan Fenton)