SCEMBLIX (Asciminib) is indicated for the treatment of adult patients with chronic myeloid leukaemia previously treated with two or more tyrosine kinase inhibitors. The drug has been approved in 2021 October by FDA.
The US prescribing informtation of SCEMBLIX says:
Concomitant use of SCEMBLIX with itraconazole oral solution containing hydroxypropyl-β-cyclodextrin decreases asciminib Cmax and AUC, which may reduce SCEMBLIX efficacy. Avoid coadministration of SCEMBLIX at all recommended doses with itraconazole oral solution containing hydroxypropyl-β-cyclodextrin. Concomitant use of oral products containing hydroxypropyl-β-cyclodextrin with SCEMBLIX other than itraconazole oral solution has not been fully characterized.
The UK Medicines & Healthcare products Regulatory Agency is more clear on pointing out the root cause of the issue:
Asciminib bioavailability may be reduced by co administration of oral medicinal products containing hydroxypropyl β cyclodextrin as an excipient.
Full characterization of Asciminib-HPBCD interaction would provide interesting insight into the mechanism and the strength of binding hindering the absorption of the drug. By all means HPBCD is rarely described as a permeation inhibiting excipient.