A novel first-in-class therapy may help to redefine survival expectations for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), according to data presented at the 2023 ASH Annual Meeting & Exposition (Abstract 547).
Results of a European named-patient program study showed significantly improved median overall survival for patients with BPDCN treated with the CD123-directed therapy tagraxofusp-erzs compared with historical controls. With more than 2 years of follow-up, median overall survival was 20 months with tagraxofusp, vs approximately 8 to 14 months with chemotherapy.
“Patients with treatment-naive BPDCN who received tagraxofusp achieved durable outcomes with prolonged survival, including those with known CNS [central nervous system] involvement,” said lead study author Emanuele Angelucci, MD, of IRCCS Ospedale Policlinico San Martino, Genova, Italy. “These real-world results from a European [named-patient program] are consistent with the long-term safety and efficacy results demonstrated in the pivotal TAG monotherapy study and further support tagraxofusp treatment for patients with BPDCN.”
Study Background
As Dr. Angelucci reported, BPDCN is an aggressive orphan hematologic malignancy that mostly presents in skin, bone marrow, and blood. The disease is characterized by clonal expansion of plasmacytoid dendritic tumor cells that express specific markers, including CD123.
Historically, according to Dr. Angelucci, median overall survival overall in this patient population has been approximately 8 to 14 months following chemotherapy. The only potential cures can be conferred by hematopoietic stem cell transplantation (HSCT) following successful induction therapy.
Tagraxofusp is a first-in-class CD123-directed therapy and the only drug approved in the United States and Europe to treat BPDCN. In August 2019, a global named-patient program was initiated in Europe to increase patient access to tagraxofusp.
The multicenter, noninterventional, retrospective study of 22 treatment-naive adults was conducted between August 2019 and December 2021. Tagraxofusp was administered intravenously as first-line therapy at 12 μg/kg once daily on days 1 to 5 (extended up to day 10 if necessary) of a 21-day cycle. Patients were hospitalized for the first cycle, and subsequent cycles could be administered in an outpatient setting.
Key Findings
The study’s primary endpoints were complete response rates and the incidence and grade of capillary leak syndrome. Secondary outcomes included the number of patients bridged to HSCT, overall survival, and safety.
The overall response rate was 89% with tagraxofusp, said Dr. Angelucci, and the complete response rate was 67%. The median times to overall response and complete response were 21 days and 29 days, respectively. Of note, 50% of the patients were bridged to HSCT. As of the data cutoff, 9% of patients remained on treatment with tagraxofusp.
Median overall survival was 20 months for all patients but was not reached in patients who received transplants. The median duration of response was 8.9 months.
Researchers also reported serious treatment-related adverse events linked to the CD123-directed therapy. Thrombocytopenia and neutropenia were the most frequent hematologic grade 3 or 4 adverse events, occurring in 32% and 18% of patients, respectively. Capillary leak syndrome was also observed in 45% of patients but was deemed largely manageable, with most events being mild to moderate. No new safety signals were observed.
Disclosure: For full disclosures of the study authors, visit ash.confex.com.
