CHICAGO – Calaspargase pegol (SC-PEG) produces similar outcomes as standard pegaspargase in pediatric and young adult patients with newly diagnosed acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL), according to a phase 2 trial.
Jennifer Smith/MDedge News
Dr. Lynda Vrooman
Patients who received SC-PEG every 3 weeks had similar serum asparaginase activity (SAA), toxicities, and survival rates as patients who received standard pegaspargase every 2 weeks.
Lynda M. Vrooman, MD, of Dana-Farber Cancer Institute in Boston, presented these results at the annual meeting of the American Society of Clinical Oncology.
The trial (NCT01574274) enrolled 239 patients, 230 with ALL and 9 with LL. Most patients had B-cell (n = 207) disease. The patients’ median age was 5.2 years (range, 1.0-20.9 years).
“There were no differences in presenting features by randomization,” Dr. Vrooman noted.
The patients were randomized to receive pegaspargase (n = 120) or SC-PEG (n = 119), a pegylated asparaginase formulation with longer half-life. SC-PEG was given at 2,500 IU/m2 every 3 weeks, and pegaspargase was given at 2,500 IU/m2 every 2 weeks.
Either asparaginase product was given as part of a 4-week induction regimen (vincristine, prednisone, doxorubicin, and methotrexate), a 3-week intensification regimen (intrathecal chemotherapy with or without radiotherapy) for central nervous system disease, and a 27-week second consolidation regimen (mercaptopurine, methotrexate, and, in high-risk patients, doxorubicin).
SAA
The researchers observed significantly longer SAA with SC-PEG during induction but not after.
During induction, at 25 days after the first asparaginase dose, 88% of patients on SC-PEG and 17% of those on pegaspargase had SAA of at least 0.10 IU/mL (P less than .001). Post-induction, at week 25, 100% of patients in each group had a nadir SAA of at least 0.10 IU/mL.
“The high nadir serum asparaginase activity levels observed for both preparations suggest dosing strategies could be further optimized,” Dr. Vrooman noted.
Safety
There were no significant differences in adverse events between the SC-PEG and pegaspargase arms during or after induction.
Adverse events during induction (in the SC-PEG and pegaspargase arms, respectively) included grade 2 or higher asparaginase allergy (0% and 1%), grade 2 or higher pancreatitis (3% in both), grade 2 or higher thrombosis (3% and 9%), grade 4 hyperbilirubinemia (3% and 1%), grade 3 or higher bacterial infection (12% and 9%), and grade 3 or higher fungal infection (4% and 5%).
Adverse events after induction (in the SC-PEG and pegaspargase arms, respectively) included grade 2 or higher asparaginase allergy (17% and 14%), grade 2 or higher pancreatitis (15% in both), grade 2 or higher thrombosis (18% and 13%), grade 4 hyperbilirubinemia (4% and 3%), grade 3 or higher bacterial infection (12% and 15%), grade 3 or higher fungal infection (2% and 1%), grade 2 or higher bone fracture (3% and 8%), and grade 2 or higher osteonecrosis (3% and 4%).
Response and survival
The complete response rate was 95% (109/115) in the SC-PEG arm and 99% (114/115) in the pegaspargase arm. Rates of induction failure were 3% (n = 4) and 1% (n = 1), respectively, and rates of relapse were 3% (n = 5) and 8% (n = 10), respectively.
There were two induction deaths and two remission deaths in the SC-PEG arm but no induction or remission deaths in the pegaspargase arm.
The median follow-up was 4 years. The 4-year event-free survival rate was 87.7% with SC-PEG and 90.2% with pegaspargase (P = .78). The 4-year overall survival rate was 94.8% and 95.6%, respectively (P = .74).
In closing, Dr. Vrooman said these data suggest SC-PEG provides similar results as standard pegaspargase. She noted that these data informed the U.S. approval of SC-PEG for pediatric and young adult ALL.
This trial was sponsored by the Dana-Farber Cancer Institute in collaboration with Shire and the National Cancer Institute. Dr. Vrooman said she had no relationships to disclose.
SOURCE: Vrooman LM et al. ASCO 2019. Abstract 10006.