ALK Mutations Conferring Differential Resistance to Structurally Diverse ALK Inhibitors

Abstract

Purpose EML4–ALK fusions define a subset of lung cancers that can be effectively treated with anaplastic lymphoma kinase (ALK) inhibitors. Unfortunately, the duration of response is heterogeneous and acquired resistance limits their ultimate efficacy. Thus, a better understanding of resistance mechanisms will help to enhance tumor control in EML4–ALK-positive tumors. Experimental Design By applying orthogonal functional mutagenesis screening approaches, we screened for mutations inducing resistance to the aminopyridine PF02341066 (crizotinib) and/or the diaminopyrimidine TAE684. Results Here, we show that the resistance mutation, L1196M, as well as other crizotinib resistance mutations (F1174L and G1269S), are highly sensitive to the structurally unrelated ALK inhibitor TAE684. In addition, we identified two novel EML4–ALK resistance mutations (L1198P and D1203N), which unlike previously reported mutations, induced resistance to both ALK inhibitors. An independent resistance screen in ALK-mutant neuroblastoma cells yielded the same L1198P resistance mutation but defined two additional mutations conferring resistance to TAE684 but not to PF02341066. Conclusions Our results show that different ALK resistance mutations as well as different ALK inhibitors impact the therapeutic efficacy in the setting of EML4–ALK fusions and ALK mutations.

Treatment Efficacy and Resistance Mechanisms Using the Second-Generation ALK Inhibitor AP26113 in Human NPM-ALK–Positive Anaplastic Large Cell Lymphoma

“…L1198F alone in our Ba/F3 cells was sufficient to confer resistance to AP26113, alectinib, ceritinib, and ASP3026; however, it was completely sensitive to Crizotinib. A methionine substitution in this position was predicted to confer resistance at AP26113 at 100 nmol/L (34), whereas a proline was predicted to confer crizotinib resistance in an in vitro screening (36). This residue corresponds to the Abl F317, a site that, if mutated, induces resistance to several TKIs.…”

Molecular characterization of pulmonary sarcomatoid carcinoma: analysis of 33 cases

“…15,[49][50][51][52] However, virtually all patients develop resistance to crizotinib therapy, usually within 1 year. [53][54][55][56][57][58][59] The higher potency ALK tyrosine kinase inhibitor ceritinib has been studied in both crizotinib-naive and crizotinib-resistant patients and has received Food and Drug Administration approval for crizotinib-resistant or -intolerant ALKrearranged lung carcinoma. 17 Alectinib is another highly potent and selective ALK inhibitor that has been granted breakthrough-therapy designation by the Food and Drug Administration for ALK-positive advanced lung carcinomas that have progressed on crizotinib therapy.…”

The R1275Q Neuroblastoma Mutant and Certain ATP-competitive Inhibitors Stabilize Alternative Activation Loop Conformations of Anaplastic Lymphoma Kinase

“…Although some mutants may display a reduced sensitivity to crizotinib, as shown for the F1174L and L1196M mutations, diminished potencies resulting from competition with tighter binding of ATP can be overcome by administering higher concentrations of inhibitor (35,57). Inhibitors with higher potencies on these ALK mutants will also be useful and reports of selected examples of such molecules have already appeared (33,52,54).…”

“…Literature IC 50 values for crizotinib inhibition of the F1174L and R1275Q ALK mutants range from 89 -130 and 67-85 nM in in vitro enzyme assays, respectively (35). In cellular assays, it is generally accepted that the F1174L mutant displays reduced sensitivity to crizotinib relative to the R1275Q mutant or to wild-type enzyme, although the reported level of reduced sensitivity varies (33,35,36,54). In the clinical setting, recent reports also identify the F1174L variant and the related F1174C variant as secondary mutations conferring resistance to crizotinib therapy in patients harboring an oncogenic ALK fusion protein (36,37).…”