Tagraxofusp Shows High Response Rate in Rare, Deadly Blood Cancer

Data from a phase 2 study shows that treatment with the drug tagraxofusp yields a high response rate in patients with a rare, deadly blood cancer that currently has no available therapies, according to the New England Journal of Medicine.

The study examined the use of tagraxofusp in patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare but highly aggressive bone marrow and blood disorder. Tagraxofusp is a novel, targeted therapy that was approved by the FDA in December 2018 for the treatment of BPDCN in adults and pediatric patients over age 2.

BPDCN can affect multiple organs, including the lymph nodes and the skin, and can present as leukemia. Patients are typically treated with chemotherapy approved for other blood cancers and/or stem cell transplants; however, many patients experience poor outcomes and low response rates.

For the study, 47 patients with untreated or relapsed BPDCN were assigned to receive either an intravenous infusion of tagraxofusp at a dose of 7 μg or 12 μg per kilogram of body weight on days 1 to 5 of each 21-day cycle. Treatment continued until disease progression or unacceptable toxic effect. The primary outcome of the study was the combined rate of complete response and clinical complete response among patients who had not received previous treatment for BPDCN.

Of the 47 patients, 32 received tagraxofusp as first-line treatment and 15 had received previous treatment. Among the 29 previously untreated patients, the study demonstrated that the primary outcome occurred in 72% and the overall response rate was 90%. Of these patients, 45% went on to undergo stem cell transplantation. Survival rates at 18 and 24 months were 59% and 52%, respectively. Among the 15 previously treated patients, the response rate was 67% and the median overall survival was 8.5 months, according to the data.

“In adults with BPDCN, tagraxofusp led to clinical responses regardless of whether patients had received previous therapy,” study author Naveen Pemmaraju, MD, associate professor at The University of Texas MD Anderson Care Center, said in a press release. “We observed high response rates including an overall response rate of 90% among frontline-treated patients. These findings offer hope for patients who have had no treatments specific to this disorder.”

Serious adverse effects associated with tagraxofusp included capillary leak syndrome, which was reported in 19% of patients. Hepatic dysfunction and thrombocytopenia were also common.

References

Pemmaraju N, Lane AA, Sweet KL, et al. Tagraxofusp in blastic plasmacytoid dendritic-cell neoplasm. New England Journal of Medicine. 2019. Doi: 10.1056/NEJMoa1815105

Study of tagraxofusp reports 90 percent response rate for deadly blood cancer with no prior available therapies [news release]. The University of Texas MD Anderson Cancer Center. https://www.mdanderson.org/newsroom/study-of-tagraxofusp-reports-90-percent-response-rate-for-deadly.h00-159302256.html. Accessed April 25, 2019.