Bluebird Falls After Brain-Wasting Drug Cleared With Caveats (1)

Bluebird Bio Inc.’s shares fell Monday after US regulators approved its gene therapy for a brain-wasting disease with a warning about cancer risks and under the condition that the drugmaker can show that it works long term.

Bluebird will charge $3 million for the treatment, Chief Executive Officer Andrew Obenshain said in an interview, the highest-ever US price for a drug. It’s a one-time treatment for children living with cerebral adrenoleukodystrophy and will be sold under the brand name Skysona.

The FDA granted what’s known as an accelerated approval. It allows Somerville, Massachusetts-based Bluebird to introduce its gene therapy ...