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Letters to the Editor
abrutinib in R/R DLBCL patients was consistent with previous studies of acalabrutinib. In addition, the observed efficacy, pharmacokinetic, and pharmacody- namic activity in this study supports further evaluation of acalabrutinib-based combinations in DLBCL.
Non-GCB DLBCL was identified per local institution immunohistochemistry using the Hans algorithm.8 A subset of patients with available tissue had central cell- of-origin testing performed by RNA profiling (NanoString Lymphoma Subtyping Test). Patients received acalabruti- nib 100 mg twice daily in repeated 28-day cycles until disease progression or unacceptable drug-related toxicity.
The primary endpoint was safety, measured by the
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incidence of adverse events (AE) from screening up to 30 days after the last acalabrutinib dose. Secondary end- points included acalabrutinib pharmacokinetics, pharma- codynamics (BTK occupancy), and efficacy. Plasma phar- macokinetic parameters were determined from plasma concentrations of acalabrutinib using non-compartmen- tal analysis. BTK occupancy was measured with enzyme- linked immunsorbent assay using a biotin-tagged ana- logue probe.7 Efficacy was measured according to inves- tigator-assessed objective response rate (ORR: CR + par- tial response [PR) based on the Lugano criteria,9 duration of response, and progression-free survival (PFS).
Twenty-one patients were enrolled; demographics and
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Figure 1. Patient-level responses. (A) Best response and maximum change in tumor burden by patient. (B) Duration of treatment with best response by patient. Arrow in panel (B) indicates the patient is continuing treatment with acalabrutinib. aBest response for one patient was unknown and thus not included in this graph. CR: complete response; ORR: overall response rate; PD: progressive disease; PR: partial response; Ref: refractory; Rel: relapsed; SD: stable disease.
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