ALK E1210K

Legal entity responsible for the study Fondazione Policlinico Universitario A Gemelli – IRCCS. In post-lorlatinib NGS-assay, 2 pts had ALK-compound mutations, while 4 pts had newly off-target alterations (CDKN2A/B CDKN2B loss, NF1 deletion, DNMT3A/ARID1A/CHECK2 M+). Conclusions Implementation of longitudinal genomic assessment is required in order to provide an extensive overview of resistance mechanisms and clinical outcomes according to current ALK-inhibitors treatment sequences.

In Cohort 1 (n=21), 15 (71%) pts had progressed on alectinib, 5 (24%) on ceritinib and 1 (5%) on ensartinib. In Cohort 2 (n=18), pts had progressed on crizotinib followed by alectinib (n=9, 50%), ceritinib (n=4, 22%) or brigatinib (n=3, 17%); 2 (11%) pts progressed on crizotinib, then ceritinib followed by alectinib...Of 5 pts with ALK resistance mutations (I1171N, V1180L, L1196M, G1202R, and E1210K) who subsequently received lorlatinib, repeat ctDNA NGS after 2 months demonstrated clearance of ALK resistance mutation(s) in 4/5 (80%) pts (i.e. undetectable on repeat testing)... Resistance mechanisms to ALK inhibitors are heterogenous, including both ALK dependent and independent pathways. DDR and cell cycle gene alterations were commonly detected and may represent previously unreported acquired resistance alterations. Comprehensive ctDNA NGS analysis at progression may help detect novel resistance alterations in patients on ALK inhibitors.

In 20 eligible patients (median [m]age 63 years [range, 40-89], females 75%, adenocarcinoma 100%, failure of alectinib 90%, FoundationOne Liquid CDx 80%), CGP has altered NLST recommendation in 30% of cases (Figure 2)... CGP has a significant impact on the decision-making process in ALK-rearranged aNSCLC following progression on 2nd/3rd-generation ALK TKIs.

In 20 eligible patients (median [m]age 63 years [range, 40-89], females 75%, adenocarcinoma 100%, failure of alectinib 90%, FoundationOne Liquid CDx 80%), CGP has altered NLST recommendation in 30% of cases...mOS was 13.2 months (95% CI, 2.9-NR) and 13.0 months (95% CI, 6.0-NR) in groups 1 and 2, respectively (p-0.86). CGP has a significant impact on the decision-making process in ALK-rearranged aNSCLC following progression on 2/3-generation ALK TKIs.

Another pt with the G1202R mutation following alectinib treatment had tumor shrinkage of 27.9%. APG-2449 has a favorable safety and PK profile and was well tolerated in 84 subjects. Preliminary efficacy was observed in pts whose disease was resistant to second-generation TKIs, especially among those with brain metastases, and in TKI-naïve pts. Biomarker data indicated potential target engagement on FAK and immunomodulatory effects of APG-2449.

The mechanisms of ALK TKI resistance were heterogeneous; ALK mutations were found in less than one-third of patients. Compound ALK mutations, which may confer lorlatinib resistance, may occur in crizotinib, ceritinib, and alectinib-resistant lung cancers.

Our study highlighted the advantage of ctDNA analysis for monitoring tumor evolution. TP53 mutations promoted genetic evolution and accelerated occurrence of resistance. We also unveiled ALK-dependent resistance mechanisms, mainly by G1269A, G1202R and E1210K mutations, and ALK-independent resistance mechanisms to ensartinib.

Consistent with previous reports, ensartinib showed high clinical efficacy. Longitudinal ctDNA analysis could be a powerful tool in predicting treatment outcomes and revealing resistant mechanisms of ensartinib. We observed G1269A, G1202R and E1210K as the major resistant mutations to ensartinib.