Tagraxofusp Elicits 90% Response Rate in Patients With Rare, Aggressive Blood Cancer

Results from a phase 2 trial demonstrated that treatment with tagraxofusp resulted in high response rates among adults with untreated or relapsed blastic plasmacytoid dendritic-cell neoplasm (BPDCN), a rare, aggressive blood cancer.

Results of the study supported the approval of the targeted therapy for adults and pediatric patients aged 2 years or older in December 2018. Now published in the New England Journal of Medicine, details from the study revealed that tagraxofusp was particularly effective in treatment-naïve patients.

“In adults with BPDCN, tagraxofusp led to clinical responses regardless of whether patients received previous therapy,” said Naveen Pemmaraju, MD, associate professor, Department of Leukemia, Division of Cancer Medicine, The University of Texas and lead author of the study, in a statement. “We observed high rates including an overall response rate of 90% among frontline-treated patients. These findings offer hope for patients who have had no treatment specific to this disorder.”

Among the 47 patients enrolled in the study between 2014 and 2017, there were 32 treatment-naïve patients, 29 of which received the recommended dose of 12 μg/kilogram. Among these patients, the primary outcome—the combined rate of complete response and clinical complete response—occurred in 21 (72%) patients, and 45% of these patients went on to undergo stem-cell transplantation.

At 18 months, the survival rate was 59% and at 24 months, the survival rate was 52%.

BPDCN, caused by transformed plasmacytoid dendritic cells that overexpress interleukin-3 receptor subunit alpha, can affect multiple organs, including the lymph nodes and skin, and often presents as or evolves into acute leukemia. With no disease-specific treatment options prior to tagraxofusp, patients have historically had poor outcomes and low response rates with chemotherapy treatment following diagnosis.

“The majority of patients are older with a median age of 68 to 72 years, an age which many patients are unable to undergo intensive chemotherapy and cannot undergo stem-cell transplantation which requires chemotherapy as a first treatment,” according to the statement from The University of Texas MD Anderson Cancer Center.

For the 15 previously treated patients in the study, the response rate was 67% and median overall survival was 8.5 months.

During the study period, the most common adverse events were increased levels of alanine aminotransferase (64%) and aspartate aminotransferase (60%), hypoalbuminemia (55%), peripheral edema (51%), and thrombocytopenia (49%).

Tagraxofusp is currently being assessed in clinical trials for other disease states, including chronic myelomonocytic leukemia and myelofibrosis.

Reference:

Pemmaraju N, Lane A, Sweet K, et al. Tagraxofusp in blastic plasmacytoid dendritic-cell neoplasm [published online April 25, 2019]. N Engl J Med. doi: 10.1056/NEJMoa1815105.