Humanwell Healthcare (Group) Co. Ltd. has described proteolysis targeting chimera (PROTAC) compounds comprising an E3 ubiquitin ligase binding moiety covalently linked to an interleukin-1 receptor-associated kinase 4 (IRAK-4) targeting moiety via a linker reported to be useful for the treatment of cancer, rheumatoid arthritis, renal disorders, multiple sclerosis, alopecia areata, urticaria, psoriasis and chronic obstructive pulmonary disease (COPD), among others.