On Sunday 3rd June an oral abstract session took place at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting. Abstract 7501 was presented by Roger Owen, St James’s University Hospital, Leeds, on acalabrutinib use in patients with Waldenström macroglobulinemia (WM).
The phase II study was a multi-center, international and open-label trial testing the use of acalabrutinib in patients with WM. Patients were either treatment-naïve (TN), n = 14, or relapsed/refractory (R/R), n = 92. Treatment with acalabrutinib was either 100mg twice daily or 200mg every day in 28-day cycles until disease progression or unacceptable toxicity. The co-primary endpoints were investigator-assessed overall response rate (ORR) based on either the 6th IWWM criteria or the modified 3rd IWWM criteria.
- ORR based on 6th IWWM criteria and modified 3rd IWWM criteria was 93% for both TN and R/R patients
- The 24-month duration of response rate for TN vs R/R
- 90% (95% CI, 47.3%, 98.5%) vs 82% (95% CI, 71.9%, 88.7%)
- 24-month progression-free survival for TN vs R/R
- 90% vs 9%
- 24-month overall survival rate for TN vs R/R
- 7% vs 88.9%
- Most common Grade ≥3 adverse events (AEs) of all patients were neutropenia (16%), lower respiratory tract infection (5%) and pneumonia (7%)
Dr Owens concluded that acalabrutinib monotherapy showed high efficacy in WM in both TN and R/R patients. He noted that the “safety profile is very good, and most AEs were of low grade and very limited number of dropouts on account of AEs.”