Intensive Asparaginase Therapy in Young Adult Patients with Acute Lymphoblastic Leukemia: Treatment Patterns and Barriers to Asparaginase Use

Background: Although considerable progress has been made in treating acute lymphoblastic leukemia (ALL) in the pediatric population, with long-term survival exceeding 80%, the prognosis for adolescents, young adult, and adult patients with ALL remains poor, with only 30%-45% of patients achieving long-term survival. Several studies suggest that young adult patients have superior overall survival when treated with intensive "pediatric-inspired" regimens that include the use of asparaginase [Dombret H, et al. Curr Hematol Malig Rep. 2014;9(2):158-164]. Despite these results, many young adult patients with ALL continue to be treated with chemotherapy regimens that include little or no asparaginase. The goal of this study was to assess the views and practices of hematologists and oncologists with respect to asparaginase use in young adult patients with ALL.

Methods: This study was conducted between May 14 and June 22, 2015, and consisted of a 10-minute online quantitative survey, with a 10-minute per-patient chart audit component for up to 4 charts provided by participating physicians. The survey targeted physicians treating young adult patients (aged 18-40 years) with ALL. To be included in the final analysis, physicians were required to be board certified with 2-30 years in practice, with ≥75% of their time spent in direct patient care and ≥20% of their time spent in an academic setting (NCCN/NCI or academic/teaching hospital). Inclusion criteria also required that physicians' total ALL patient volume (young adults and adults aged >40 years) was greater than 5 over the past 2 years, that the physician primarily treats adult patients, and has personally managed and treated at least 1 young adult ALL patient in the past 2 years.

Results: The study included results reported by a total of 63 practicing physicians for 189 young adult patients with ALL (62% were aged 25-40 years). Sixty percent (114/189) of young adult patients were treated with a protocol that included asparaginase, and only 29% (55/189) on a pediatric-inspired protocol. The most common protocols reported for patients receiving asparaginase included the pediatric-inspired CALGB 10403 (18%, 21/114), as well as regimens with more limited asparaginase use, including augmented hyper-CVAD (29%, 33/114) and CALGB 8811 (12%, 14/114). Overall 40% (75/189) of young adult patients were treated with protocols that did not include asparaginase, most commonly hyper-CVAD (77%, 58/75). Fifty percent (18/36) of responding physicians using hyper-CVAD reported the perception of similar outcomes with nonasparaginase regimens as with asparaginase-intensive regimens. When questioned about the greatest barrier to the use of intensive asparaginase-containing regimens, 88% (7/8) of responding physicians reported safety and tolerability concerns.

Conclusion: Only 6 out of 10 patients in the study were treated with an asparaginase-containing regimen; of all patients, less than 1 out of 3 received a pediatric-inspired regimen. Fifty-three percent (60/114) of asparaginase-receiving patients were treated on a regimen that structures asparaginase dosing intermittently between alternating courses. Pediatric-inspired regimens include intensive asparaginase therapy and have consistently shown improvements in overall survival when compared with traditional adult protocols in clinical trials [Dombret H, et al. Curr Hematol Malig Rep. 2014;9(2):158-164].

Support: This study was funded by Jazz Pharmaceuticals.