Inactivation rates of 5 covalent BTK inhibitors.³⁵ The corresponding free energy of activation ΔG^‡ values (calculated using transition state theory) are shown for comparison.

Inhibitor	BTK inactivation rate, kinact (s−1)	Free energy of inactivation ΔG‡ (kcal mol−1)
Ibrutinib	2.66 × 10−2	19.6
Acalabrutinib	5.59 × 10−3	20.5
Zanubrutinib	3.33 × 10−2	19.5
Spebrutinib	1.36 × 10−2	20.0
Tirabrutinib	9.72 × 10−2	20.2