What happened

Shares of Stemline Therapeutics (STML) were down 34% at 11:42 a.m. EST after the company released disappointing preliminary fourth-quarter results.

So what

The biotech estimates that it sold $11.8 million worth of Elzonris, a drug that treats blastic plasmacytoid dendritic cell neoplasm (BPDCN), a type of blood cancer. That's lower than the $13.1 million Stemline Therapeutics sold in the third quarter -- when, as the company noted, the number of new patients on the drug increased by over 20% quarter over quarter.

Management didn't give much color on the reason for the quarter-over-quarter decline in the press release, but the company has noted in the past that BPDCN is often misdiagnosed, and it was working with doctors to increase the speed and accuracy of diagnoses. Management will likely update investors on the progress and reason for the sales slowdown during the company's presentation at the J.P. Morgan Healthcare Conference on Wednesday.

Doctor talking to a patient in an exam room

Image source: Getty Images.

Now what

The slowdown in launch trajectory is certainly disappointing, but Stemline Therapeutics has plenty of opportunities to turn things around. Elzonris is under review by EU regulators, setting up a likely approval this year.

Further down the line, there's potential to expand Elzonris into other blood cancers; the company is currently testing the drug in three different blood cancers -- chronic myelomonocytic leukemia, myelofibrosis, and acute myeloid leukemia -- with clinical trial data in all three expected this year. There's also potential to move Elzonris into the maintenance setting for patients treating their BPDCN through a stem cell transplant; initial data in that setting is expected this quarter.