BRAF V600E mutation as a novel mechanism of acquired resistance to ALK inhibition in ALK-rearranged lung adenocarcinoma: A case report

Combined BRAF G469A mutation and echinoderm microtubule associated protein like-4-anaplastic lymphoma kinase rearrangement with resistance: A case report and review of literature

BACKGROUND

Through deeper understanding of targetable driver mutations in non-small-cell lung cancer (NSCLC) over the past years, some patients with driver mutations have benefited from the targeted molecular therapies. Although the anaplastic lymphoma kinase and BRAF mutations are not frequent subtypes in NSCLC, the availability of several targeted-drugs has been confirmed through a series of clinical trials. But little is clear about the proper strategy in rare BRAF G469A mutation, not to mention co-exhibition of anaplastic lymphoma kinase and BRAF G469A mutations, which is extremely rare in NSCLC.

CASE SUMMARY

We present a patient to stage IVA lung adenocarcinoma with coexisting echinoderm microtubule associated protein like-4 rearrangement and BRAF G469A mutation. She received several targeted drugs with unintended resistance and suffered from unbearable adverse events.

CONCLUSION

Due to the rarity of co-mutations, the case not only enriches the limited literature on NSCLC harbouring BRAF G469A and echinoderm microtubule associated protein like-4 mutations, but also suggests the efficacy and safety of specific multiple-drug therapy in such patients.

A real world analysis of secondary BRAF variations after targeted therapy resistance in driver gene positive NSCLC

Secondary BRAF variations have been identified as a mechanism of resistance to tyrosine kinase inhibitors (TKIs) in patients with driver gene-positive NSCLC. Nevertheless, there is still a lack of consensus regarding the characteristics and subsequent treatment strategies for these patients. We retrospectively reviewed the medical records of patients with driver gene-positive NSCLC who received TKIs therapy at Zhejiang Cancer Hospital between May 2016 and December 2023. The clinical and genetic characteristics of these patients were assessed, along with the impact of various treatment strategies on survival. This study enrolled 27 patients with advanced NSCLC, in whom BRAF variations occurred at a median time of 28 months after the initiation of targeted therapy. The multivariate accelerated failure time (AFT) model revealed that, compared to chemotherapy-based regimens group, the combined targeted therapy group (p < 0.001) and the combined local treatment group for oligo-progression (p < 0.001) significantly extended patient survival. In contrast, continuing the original signaling pathway's targeted monotherapy was associated with shorter survival (p = 0.034). The median global OS for each treatment group was as follows: chemotherapy-based regimens group, 45 months; combined targeted therapy group, 59 months; combined local treatment group for patients with oligo-progression, 46 months; and targeted monotherapy group, 36 months. Study results indicate that the combination targeted therapy group (including TKIs, BRAF inhibitors, and/or MEK inhibitors) and the localized treatment group are more effective than traditional chemotherapy-based regimens in improving survival. Additionally, continuing targeted monotherapy along the original signaling pathway proves less effective than chemotherapy-based regimens.

Pathways and targeting avenues of BRAF in non-small cell lung cancer

INTRODUCTION

BRAF is a serine-threonine kinase implicated in the regulation of MAPK signaling cascade. BRAF mutation-driven activation occurs in approximately 2-4% of treatment-naive non-small cell carcinomas (NSCLCs). BRAF upregulation is also often observed in tumors with acquired resistance to receptor tyrosine kinase inhibitors (TKIs).

AREAS COVERED

This review describes the spectrum of BRAF mutations and their functional roles, discusses treatment options available for BRAF p.V600 and non-V600 mutated NSCLCs, and identifies some gaps in the current knowledge.

EXPERT OPINION

Administration of combined BRAF/MEK inhibitors usually produces significant, although often a short-term, benefit to NSCLC patients with BRAF V600 (class 1) mutations. There are no established treatments for BRAF class 2 (L597, K601, G464, G469A/V/R/S, fusions, etc.) and class 3 (D594, G596, G466, etc.) mutants, which account for up to two-thirds of BRAF-driven NSCLCs. Many important issues related to the use of immune therapy for the management of BRAF-mutated NSCLC deserve further investigation. The rare occurrence of BRAF mutations in NSCLC is compensated by high overall incidence of lung cancer disease; therefore, clinical studies on BRAF-associated NSCLC are feasible.

Case report: BRAF A598-T599insV mutation as a potential resistance mechanism to alectinib in ALK-rearranged lung adenocarcinoma

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) have improved the prognosis of advanced-stage non-small cell lung cancer (NSCLC) with ALK rearrangement, but resistance mechanisms limit their efficacy. We describe the case of a 63-year-old man with a stage cIVA ALK-rearranged lung adenocarcinoma who developed a BRAF A598-T599insV mutation as a potential resistance mechanism to alectinib, a second-generation ALK TKI. He was treated with an association of BRAF and MEK inhibitors but death occurred two months after treatment initiation in a context of tumor progression and toxicity. Based on this first report of BRAF A598-T599insV mutation occurring in lung cancer, we discuss resistance mechanisms to ALK TKIs, implications of BRAF mutation in NSCLC, and BRAF A598-T599insV mutation in other cancers.

Lung adenocarcinoma harboring complex EML4-ALK fusion and BRAF V600E co-mutation responded to alectinib

RATIONALE

The echinoderm microtubule-associated protein-like 4 gene and anaplastic lymphoma kinase gene (EML4-ALK) is the most frequent fusion variant of ALK rearrangements in non-small cell lung cancer (NSCLC). With the widespread application of next-generation sequencing (NGS), more fusions and co-mutations of EML4-ALK have been discovered. Complex co-mutation of EML4-ALK fusions together with BRAF V600E, though rarely occurred, also deserves attention to determine the standard of caring these patients. Herein, we report a case of lung adenocarcinoma harboring a complex ALK fusion that coexisted with a BRAF mutation, as tested by DNA-NGS prior to treatment.

PATIENT CONCERNS

A 51-year-old non-smoking man, without any symptoms, was admitted to hospital due to small pulmonary nodules and enlarged supraclavicu larlymph nodes found in health checkup.

DIAGNOSIS

He was diagnosed with stage IVB (T4N3M1c) lung adenocarcinoma. BRAF V600E (abundance 3.75%) mutation and a novel thus little-understood EML4-ALK (E13, A5; abundance 2.16%) fusion were identified by DNA-NGS analysis of lymph node biopsy tissue in December 2019.

INTERVENTIONS

Darafenib plus trametinib targeted therapy and chemotherapy were given firstly, but tumor progression was not inhibited. The ALK inhibitor alectinib was prescribed then.

OUTCOMES

The patient exhibited a rapid disease response to ALK tyrosine kinase inhibitors alectinib with a complete remission of widespread metastatic disease and progression-free survival of more than 26 months, but not to darafenib plus trametinib targeted BRAF V600E therapy. Re-analyzed the patient's DNA-NGS original data, showed it is a rare and complex EML4-ALK (E13, A5, A20) fusion in fact. Additional RNA-NGS analysis showed it verified to be a canonical EML4-ALK (E13, A20) fusion transcript and coexisting with a BRAF V600E mutation.

LESSONS

This case suggests that for patients with rare or complex EML4-ALK fusions at DNA level, additional RNA-NGS is necessary to verify its functionality as early as possible. Targeting EML4-ALK firstly may be more preferable despite the coexisting of BRAF V600E.

Third-generation EGFR and ALK inhibitors: mechanisms of resistance and management

The discoveries of EGFR mutations and ALK rearrangements as actionable oncogenic drivers in non-small-cell lung cancer (NSCLC) has propelled a biomarker-directed treatment paradigm for patients with advanced-stage disease. Numerous EGFR and ALK tyrosine kinase inhibitors (TKIs) with demonstrated efficacy in patients with EGFR-mutant and ALK-rearranged NSCLCs have been developed, culminating in the availability of the highly effective third-generation TKIs osimertinib and lorlatinib, respectively. Despite their marked efficacy, resistance to these agents remains an unsolved fundamental challenge. Both 'on-target' mechanisms (largely mediated by acquired resistance mutations in the kinase domains of EGFR or ALK) and 'off-target' mechanisms of resistance (mediated by non-target kinase alterations such as bypass signalling activation or phenotypic transformation) have been identified in patients with disease progression on osimertinib or lorlatinib. A growing understanding of the biology and spectrum of these mechanisms of resistance has already begun to inform the development of more effective therapeutic strategies. In this Review, we discuss the development of third-generation EGFR and ALK inhibitors, predominant mechanisms of resistance, and approaches to tackling resistance in the clinic, ranging from novel fourth-generation TKIs to combination regimens and other investigational therapies.

Genetic correlation of crizotinib efficacy and resistance in ALK- rearranged non-small-cell lung cancer

OBJECTIVES

Crizotinib remains one of the most commonly used targeted therapies for ALK fusion-positive patients. However, the mutational profiles and mechanisms of resistance to first-line crizotinib treatment remain to be thoroughly examined.

MATERIALS AND METHODS

We retrospectively reviewed 125 ALK-positive patients with histological and/or cytological diagnosis of NSCLC. Of these, baseline samples were available from 62 patients and 63 had resistance samples following first-line crizotinib treatment, with 18 patients having paired baseline and resistance samples. All patients were genetically profiled by NGS using a 139 lung cancer gene panel (Pulmocan®, Nanjing Geneseeq Technology Inc.). Survival associations of progression-free survival (PFS) and resistance mechanisms were evaluated in relation to ALK fusion variants and background genetic alterations.

RESULTS

The median age of the cohort was 53 years old (range 26-78; 46.4 % females). Three novel ALK fusion partners were identified, including PSME4, cullin3 (CUL3) and coiled-coil domain containing 85A (CCDC85A). Among the different ALK fusion genes, patients carrying the v3 variant experienced worse PFS outcome compared with other non-v3 fusions (P = 0.01) in response to first-line crizotinib. Profiling of the genetic landscape revealed TP53 as the most frequently co-mutated gene, alterations of which were associated with unfavorable outcome (P = 0.024) and were among the secondary acquired mutations in the resistance samples. Examinations of the resistance mechanisms showed that the v3 variant was more likely to acquire ALK activating mutations (P = 0.04). Off-target resistance mechanisms included mutations in genes in the RAS/MAPK and its parallel pathway genes, such as ERBB2, BRAF, KRAS, FGFR3, NF1 and CREBBP.

CONCLUSION

In this study, through profiling of the mutational landscape of ALK-positive advanced NSCLCs both at baseline and disease progression, we characterized resistance mechanisms and molecular correlations of PFS in response to first-line crizotinib. Our findings may facilitate rational selection of subsequent ALK TKIs in the clinic.

Lorlatinib as a treatment for ALK-positive lung cancer

Lorlatinib, a third-generation ALK tyrosine kinase inhibitor, has been approved as a treatment for ALK-positive lung cancer. This review provides information regarding the pharmacology and clinical features of lorlatinib, including its efficacy and associated adverse events. Pivotal clinical trials are discussed along with the current status of lorlatinib as a treatment for ALK-positive lung cancer and future therapeutic challenges.

The clinical and prognostic role of ALK in glioblastoma

BACKGROUND

anaplastic lymphoma kinase (ALK) overexpression and gene alterations have been detected in several malignancies, with prognostic and therapeutic implications. However, few studies investigated the correlation between ALK altered expression and prognosis in patients with glioblastoma (GBM).

METHODS

We performed an evaluation of ALK overexpression and structural/quantitative chromosome alterations through immune-histochemical assay (IHC with D5F3 antibody) and fluorescent in situ hybridization (FISH) in patients with isocitrate dehydrogenase (IDH) wild type (wt) GBM. Assuming an ALK overexpression in 20 % of patients we planned a sample of 44 patients to achieve a probability of 90 % to include from 10 % to 30 % of patients with ALK alterations.

RESULTS

We evaluated 44 patients with IDH wt GBM, treated in our institution and dead due to GBM progression in 2017. ALK overexpression obtained by a composed score (the product of IHC intensity staining and rate of positive cells) was observed in 19 (43 %) patients. FISH analysis showed that 11 patients (25 %) had gene deletion, 2 patients (4.5 %) had monosomy and one patient (2.3 %) presented polysomy. Only one patient (2.3 %) demonstrated ALK rearrangement. There was no statistical difference in median OS between patients with ALK-positive (mOS = 18.9 months) and ALK-negative IHC (mOS = 18.0 months).

CONCLUSION

We identified some rare previously unreported alterations of ALK gene in patients with IDH wt GBM. In these patients, the ALK overexpression does not influences survival.