SAN FRANCISCO – Vertex Pharmaceuticals Inc., of Boston, said it expects 3,700 people with cystic fibrosis to be eligible to receive its therapy for the genetic disease, Kalydeco (ivacaftor), by end of 2015, supporting continued growth of the drug's global sales, which it said are likely to rise to between $560 million and $580 million as the company moves to expand its geographic reach and address the needs of more patients.