How long will it take for drug resistance to lorlatinib/lorlatinib to develop?

Lorlatinib/Lorlatinib (Lorlatinib) is an effective brain-penetrating drug and a third-generation anaplastic lymphoma kinase inhibitor (ALK) TKI that can solve the resistance mechanism after previous ALK TKIs treatment. In a global Phase II study, lorlatinib demonstrated promising overall and intracranial activity in pre-treated patients with ALK-positive non-small cell lung cancer. These results led to regulatory approval of lorlatinib by many drug regulatory agencies. The time to emergence of drug resistance varies between individuals and is affected by multiple factors.

The mechanisms of drug resistance usually include, but are not limited to, genetic mutations within tumor cells, upregulation of drug efflux pumps, and changes in the tumor microenvironment. For example, some patients may develop new ALK gene mutations after receiving lorlatinib, and these mutations can make tumor cells resistant to the drug. In addition, tumor cells may increase the expression of drug efflux pumps, reducing the intracellular concentration of the drug, thus reducing its efficacy. Some patients may also escape the inhibitory effect of lorlatinib by activating other signaling pathways, such as the EGFR or MET pathways.

Since the publication of the global Phase II trial, the clinical benefit of lorlatinib in the post-second-generation setting has been confirmed in multiple real-world cohorts, with median progression-free survival (PFS) and duration of treatment (DoT) 6.2-9.9 months and 4.4-11.8 months, respectively. Once a patient develops drug resistance, it usually affects the next treatment plan. Doctors may consider switching to other targeted drugs, chemotherapy, or combination treatment regimens to address the challenges posed by drug resistance. Understanding the mechanisms of drug resistance and its onset time is of great significance for optimizing treatment options for non-small cell lung cancer and improving patient survival rates.