Jazz Pharmaceuticals PLC agreed to buy Celator Pharmaceuticals Inc. in a roughly $1.5 billion deal that represents a huge premium for a company with a promising leukemia drug but no revenue.

In confirming earlier news of the deal, Jazz JAZZ, +1.24% said it is paying $30.25 a share in cash for Celator US:CPXX, a 72% premium to Celator’s previous closing share price of $17.53. That represents a big price even in biotechnology, where acquirers often pay up for promising new treatments.