TABLE 5.

Isoform‐specific ALDH inhibitors

Compound name	Mechanism of action	Cellular activity	Animal studies	Ref.
Cpd 3	Competitive ALDH1A1 inhibition	IC50: 20 nM for ALDH1A1	No in vivo studies	271
CM026	Competitive ALDH1A1 inhibition	IC50: 0.8 μM for ALDH1A1	No in vivo studies	272
CM037	Competitive ALDH1A1 inhibition	IC50: 4.6 μM for ALDH1A1	Ineffective in vivo	272 , 273 , 274
NCT‐501	Competitive ALDH1A1 inhibition	IC50: 0.04 μM	Ineffective in vivo	274 , 275 , 276
NCT‐505/NCT‐506	ALDH1A1 inhibition	IC50: 7 nM for ALDH1A1	NCT‐505 and NCT‐506 have reasonable systemic drug exposure when administered orally	274
13 g/13 h	Noncovalent, noncompetitive ALDH1A inhibition	IC50 (13 g): 80 nM for ALDH1A1, 250 nM for ALDH1A2, 120 nM for ALDH1A3; IC50 (13 h): 270 nM for ALDH1A1, 480 nM for ALDH1A2, 130 nM for ALDH1A3	No in vivo studies	277
CVT‐10216	Reversible ALDH2 inhibition	IC50: 29 nM for ALDH2	No in vivo studies	278
ALDH423	ALDH2 inhibition	IC50: 0.62 μM for ALDH2	No in vivo studies	279
CB7	Competitive ALDH3A1 inhibition	IC50: 0.2 μM for ALDH3A1	No in vivo studies	280
CB29	Reversible ALDH3A1 inhibition	IC50: 16 μM for ALDH3A1	No in vivo studies	281
Acivicin	Covalent ALDH4A1 inhibition	IC50: 5.4 μM for ALDH4A1	No in vivo studies	282

Abbreviation: IC50, inhibitory concentration.