Isis Pharmaceuticals Inc. has done scores of deals over its 24-year history, collecting about $2.2 billion in partnering revenues along the way. But while partnering has always been the lynchpin of the biotech's business model, Chairman and CEO Stanley Crooke says the company's fourth deal with Biogen Idec Inc. is the first of a "new vintage" of strategic transactions.

Aside from the $100 million upfront price tag - Isis' biggest yet for a discovery pact - "Biogen 4" is different from all the earlier deals because it ties Isis to Biogen in a long-term relationship for an entire therapeutic area: neurology.