Cuba has approved what is believed to be the world's first registered lung cancer vaccine and is offering it to Cuban and foreign patients in its hospitals.

The therapeutic vaccine CimaVax EGF extends life with few side effects, and is another step in Cuba's expertise in biotechnology. It was unveiled on Monday at Havana's centre of molecular immunology.

It has been shown to boost survival rates by an average of four to five months, and in some cases much longer. It does not prevent lung cancer. Unlike chemotherapy, CimaVax EGF is said to have few side effects because it is a modified protein which attacks only cancer cells.

"It's the first such vaccine registered in the world," said Gisela González, who headed the project begun in 1992. The drug is in various clinical trials, some in Canada and Britain, and is expected to be approved next in Peru.

Several companies had been licensed to market the vaccine, but it will be made in Cuba, said González. It has been approved for trial in the United States but use there is at least two years away, she added.

The vaccine triggers an immune response which, in addition to extending life, can ease symptoms such as difficulty breathing and lack of appetite. The idea was to "maintain or consolidate" the effects of chemotherapy and radiotherapy.

Tania Crombet, the centre's director of clinical investigations, said foreigners were welcome for treatment, though its cost had not yet been set. "It's possible to provide this vaccine to any patient. Because it's available in Cuba, it's approved by the Cuban drug agency, so we can receive patients from outside."

As well as helping the health services of other countries with its abundance of doctors, Cuba has used its clinics to draw thousands of overseas patients each year. Its scientists are respected by foreign peers as producing good results on tiny budgets. Fidel Castro championed biotechnology in the 1980s; by the 1990s Cuba had produced and marketed vaccines for meningitis B and hepatitis B.