3rd Stemline Patient Died in Clinical Trial One Day Before $45 Million Public Offering
February 2, 2017
By Mark Terry, BioSpace.com Breaking News Staff
New York-based Stemline Therapeutics seems to be dancing a fine line with how it is releasing negative details about its clinical trials. Adam Feuerstein, writing for TheStreet, notes that one day before a $45 million stock offering, a patient died from a severe side effect related to its drug SL-401—and that was the third patient death with the same cause.
Stemline Therapeutics is a clinical stage drug company with three clinical stage product candidates, SL-401, SL-801, and SL-701. SL-401 is directed to the interleukin-3 receptor (CD123) observed on numerous malignancies.
On December 5, 2016, the company gave an oral presentation of positive clinical data of its Phase II trial of SL-401 in patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN). It was given at the 2016 American Society of Hematology (ASH) Annual Meeting in San Diego. The results showed a 100 percent (16/16) overall response rate, as well as an 81 percent (13/16) complete response rate in first-line BPDCN patients treated at the recommended dose of 12 ug/kg/day, and a 95 percent (18/19) ORR in first-line patients treated at the recommended dose.
Naveen Pemmaraju, assistant professor, Department of Leukemia at the University of Texas MD Anderson Cancer Center in Houston, TX, an investigator in the study, said in a statement, “The encouraging results generated to date with SL-401 continue to indicate the agent could very well emerge as the standard of care for both first-line and relapsed/refractory BPDCN, a devastating disease for which there had previously been no effective therapy.”
On January 20, 2017, the company announced the pricing of an underwritten public offering of 4.5 million shares of its common stock at $10 per share, with expected proceeds to hit $45 million.
But, per Feuerstein, the day before the financing, a patient in the trial died from capillary leak syndrome. It was the third death due to capillary leak syndrome, and hasn’t been reported by the company, but was confirmed by a member of the patient’s family. He writes, it “is potentially troubling because it occurred after Stemline had already increased safety monitoring and added new dosing rules to reduce the incidence and severity of the side effect.”
Capillary leak syndrome involves large amounts of blood fluid leaking into the body cavity from blood vessels. The results are swelling and dramatic decrease in blood pressure that can lead to organ failure and death. It is very rare.
Feuerstein writes, “To date, SL-401 has demonstrated robust overall tumor response rates of 84%, including 56% complete or near-complete response in patients enrolled in its clinical trial. But the drug is also now tied to three patient deaths.”
The company is working to finish enrollment totaling about 50 patients in the Phase II study by the end of this quarter. Stemline hopes to use the result of the trial for a marketing application to the U.S. Food and Drug Administration (FDA) by the end of the year.
When asked about the death of the BPDCN patient on January 18, Ken Hoberman, Stemline’s chief operating officer, stated, “We are not in a position to comment about any specific outcomes that may or may not have occurred in any of our existing trials. As you know, in any trial of an experimental agent for patients with advanced cancer, patient deaths often occur. When deaths occur in a trial, then careful analysis must be done to understand probable causes and relation, if any, of the death to the use of the experimental product. It would be inappropriate for Stemline to comment on the death of any patient or patients in a trial, including any trial of SL-401, until such an analysis has been conducted, has concluded, and has yielded any information that should be shared publicly.”
It’s the timing of the death and the public offering that causes the problem.
According to filings with the U.S. Securities and Exchange Commission (SEC), one BPDCN patient died from capillary leak syndrome. A second patient died, who was on the drug for advanced acute myeloid leukemia, apparently of the same diagnosis.
The third patient, whose sister spoke with TheStreet, received the first two doses of SL-401 on January 12 and 13. Feuerstein writes, “Her third daily infusion was postponed because of deteriorating health due to side effects. On January 17, the patient was diagnosed with capillary leak syndrome. She died the next day, never having received three of the scheduled five doses of SL-401 in the initial treatment cycle of the clinical trial.”
Stemline had implemented more safety precautions after a dose-ranging stage of the Phase II trial to cut the risk of capillary leak syndrome, and the data presented as ASH didn’t report severe capillary leak syndrome. “But,” Feuerstein writes, “that clean safety streak ended with the death of the BPDCN patient on January 18, raising concerns that Stemline may not have the risk of fatal capillary leak syndrome under control.”
Stemline is currently trading for $9.75.