Particular caution must be used when prescribing Kaletra and medicinal products known to induce QT interval prolongation. Indeed, Kaletra could increase concentrations of the co-administered medicinal products and this may result in an increase of their associated cardiac adverse events. Cardiac events have been reported with Kaletra in preclinical studies; therefore, the potential cardiac effects of Kaletra cannot be currently ruled out. There is risk of increased adverse events due to higher serum concentrations because of CYP3A4 inhibition by lopinavir/ritonavir requiring careful monitoring of the tolerance of this anticancer agent. 
Kaletra Summary of Product Characteristics, AbbVie Ltd, January 2021.

Coadministration is expected to increase nilotinib concentrations. A decrease in the dosage or an adjustment of the dosing interval of nilotinib may be necessary for patients requiring co-administration with strong CYP3A inhibitors such as Kaletra. Please refer to the nilotinib prescribing information for dosing instructions.
Kaletra Prescribing Information, AbbVie Inc, October 2020.