A First Take On Stemline's Pivotal BPDCN Study Patient Death

Despite a January 18 patient death during Stemline Therapeutics Inc STML’s ongoing SL-401 trials, Ladenburg Thalmann reiterated a Buy rating on the company, the blastic plasmacytoid dendritic cell neoplasm (BPDCN) treatment study of which is continuing to enroll new participants.

“Overall, despite the unfortunate death given the overwhelming unmet clinical need for BPDCN, we believe the data continue to strongly support the approval of SL-401 if the efficacy for the new cohort of patients is consistent with the prior data,” analysts wrote in a Friday memo. “We are disappointed on how this information was released and believe it created unnecessary confusion and obscured the very attractive risk/benefit profile of SL-401 in BPDCN.”

Stemline Shares Take A Hit

Shares of Stemline had plunged 35.4 percent Thursday after news broke of the death — and of the company’s failure to disclose it to investors before offering 4.5 million new shares January 20.

Analysts said they believed the company alerted the U.S. Food and Drug Administration to the incident, but the FDA had not put the trial on hold.

While the cause of death is still under investigation, the patient reportedly developed capillary leak syndrome, a well-known possible side effect of SL-401. In the study’s history, Stemline had reported two other CLS-related deaths — each in the early phases of clinical development during dose escalation.

Stemline's Policy Issue

Stemline subsequently issued a policy of interrupting SL-401 dosing based on patient albumin levels. This measure “effectively reduced the severity of CLS (no severe cases were observed) and no additional deaths occurred,” according to Ladenburg Thalmann.

Depending on the confirmed cause of the latest death, CLS-related losses represent about 1.7 percent to 2.5 percent of Stemline’s 118 BPDCN cases. Ladenburg Thalmann wrote that the frequency is “very low” compared to those of other treatments, such as chemotherapy and CAR-T.

Elsewhere In The Space

Furthermore, the FDA has approved other drugs warning of possible CLS-related death, so the firm views the recent incident with little apprehension about the Stemline name.

Because the company has reported near completion of participant enrollment, Ladenburg Thalmann expects a safety and efficacy update soon. Stemline is on track to file a Biologics License Application in the second half of 2017.

Shares are presently trading around $6.32 — significantly lower than analysts' price target of $41.