With one in-licensed product in the clinic and compounds from its internal pipeline in preclinical development, Cubist Pharmaceuticals Inc. took a step toward filling out its pipeline last week when it acquired rights to an oral formulation of ceftriaxone from International Health Management Associates Inc. An infusion of $150 million in financings earlier this year provided CBST with the wherewithal to branch out, and the product it chose, which booked $1.2 billion in sales for