What happened?

After presenting data showing a very high response rate to a clinical-stage drug in early state development, shares in bluebird bio (BLUE -1.91%) jumped 32.6% in June, according to S&P Global Market Intelligence

So what?

The company is one of a slate of intriguing biotechs that are working on therapies that reengineer a patient's T-cells so that they can spot and destroy cancer cells.

A microphone is set up for a presentation.

Image Source: Getty Images.

At the annual American Society of Clinical Oncology conference last month, bluebird bio said that its bb2121, a treatment it's developing with Celgene Corp (CELG) delivered a 100% response rate in evaluable, heavily pre-treated, multiple myeloma patients. Patients participating in the trial had previously tried and failed on a median of seven prior treatments.

The news was encouraging because it suggests that bb2121 could someday become an important weapon in the battle against multiple myeloma, a multibillion dollar indication that's already dominated by Celgene's Revlimid and Pomalyst. Revlimid and Pomalyst sales were $1.9 billion and $364 million in the first quarter, respectively.

Now what?

The impressive findings will need to be duplicated in larger studies before we can say for sure that bluebird bio has a winner on its hands. Cancer drug development is notoriously difficult, and often treatments that work in small trials fail to pan out in bigger studies.

Nevertheless, the 100% response rate is impressive and it makes bluebird bio's stock worth watching. If future bb2121 studies deliver similarly strong data, then it could win use after Revlimid and Pomalyst, and that could translate into hundreds of millions of dollars in sales, or more.