Targeted Therapy in BRAF p.K601E-Driven NSCLC: Case Report and Literature Review

Expanding Broad Molecular Reflex Testing in Non-Small Cell Lung Cancer to Squamous Histology

Due to the success story of biomarker-driven targeted therapy, most NSCLC guidelines agree that molecular reflex testing should be performed in all cases with non-squamous cell carcinoma (non-SCC). In contrast, testing recommendations for squamous cell carcinoma (SCC) vary considerably, specifically concerning the exclusion of patients of certain age or smoking status from molecular testing strategies. We performed a retrospective single-center study examining the value of molecular reflex testing in an unselected cohort of 316 consecutive lung SCC cases, tested by DNA- and RNA-based next-generation sequencing (NGS) at our academic institution between 2019 and 2023. Clinicopathological data from these cases were obtained from electronic medical records and correlated with sequencing results. In 21/316 (6.6%) cases, we detected an already established molecular target for an approved drug. Among these were seven cases with an EGFR mutation, seven with a KRAS G12C mutation, four with an ALK fusion, two with an EGFR fusion and one with a METex14 skipping event. All patients harboring a targetable alteration were >50 years of age and most of them had >15 pack-years, questioning restrictive molecular testing strategies. Based on our real-world data, we propose a reflex testing workflow using DNA- and RNA-based NGS that includes all newly diagnosed NSCLC cases, irrespective of histology, but also irrespective of age or smoking status.

DNA Sequencing of CD138 Cell Population Reveals TP53 and RAS-MAPK Mutations in Multiple Myeloma at Diagnosis

Multiple myeloma is a hematologic neoplasm caused by abnormal proliferation of plasma cells. Sequencing studies suggest that plasma cell disorders are caused by both cytogenetic abnormalities and oncogene mutations. Therefore, it is necessary to detect molecular abnormalities to improve the diagnosis and management of MM. The main purpose of this study is to determine whether NGS, in addition to cytogenetics, can influence risk stratification and management. Additionally, we aim to establish whether mutational analysis of the CD138 cell population is a suitable option for the characterization of MM compared to the bulk population. Following the separation of the plasma cells harvested from 35 patients newly diagnosed with MM, we performed a FISH analysis to detect the most common chromosomal abnormalities. Consecutively, we used NGS to evaluate NRAS, KRAS, BRAF, and TP53 mutations in plasma cell populations and in bone marrow samples. NGS data showed that sequencing CD138 cells provides a more sensitive approach. We identified several variants in BRAF, KRAS, and TP53 that were not previously associated with MM. Considering that the presence of somatic mutations could influence risk stratification and therapeutic approaches of patients with MM, sensitive detection of these mutations at diagnosis is essential for optimal management of MM.

Clinicopathological analysis of BRAF and non-BRAF MAPK pathway-altered gliomas in paediatric and adult patients: a single-institution study of 40 patients

AIMS

Mitogen-activated protein kinase (MAPK) pathway alteration is a major oncogenic driver in paediatric low-grade gliomas (LGG) and some adult gliomas, encompassing BRAF (most common) and non-BRAF alterations. The aim was to determine the frequency, molecular spectrum and clinicopathological features of MAPK-altered gliomas in paediatric and adult patients at our neuropathology site in Kuwait.

METHODS

We retrospectively searched the data of molecularly sequenced gliomas between 2018 and 2023 for MAPK alterations, revised the pathology in view of the 2021 WHO classification and evaluated the clinicopathological data for possible correlations.

RESULTS

Of 272 gliomas, 40 (15%) harboured a MAPK pathway alteration in 19 paediatric (median 9.6 years; 1.2-17.6) and 21 adult patients (median 37 years; 18.9-89.2), comprising 42% and 9% of paediatric and adult cases, respectively. Pilocytic astrocytoma and glioblastoma were the most frequent diagnoses in children (47%) and adults (43%), respectively. BRAF V600E (n=17, 43%) showed a wide distribution across age groups, locations and pathological diagnoses while KIAA1549::BRAF fusion (n=8, 20%) was spatially and histologically restricted to cerebellar paediatric LGGs. Non-V600E variants and BRAF amplifications accompanied other molecular aberrations in high-grade tumours. Non-BRAF MAPK alterations (n=8) included mutations and gene fusions involving FGFR1, NTRK2, NF1, ROS1 and MYB. Fusions included KANK1::NTRK2, GOPC::ROS1 (both infant hemispheric gliomas), FGFR1::TACC1 (diffuse LGG), MYB::QKI (angiocentric glioma) and BCR::NTRK2 (glioblastoma). Paradoxical H3 K27M/MAPK co-mutations were observed in two LGGs.

CONCLUSION

The study provided insights into MAPK-altered gliomas in Kuwait highlighting the differences among paediatric and adult patients and providing a framework for planning therapeutic polices.

Clinicogenomic Features and Targetable Mutations in NSCLCs Harboring BRAF Non-V600E Mutations: A Multi-Institutional Genomic Screening Study (LC-SCRUM-Asia)

INTRODUCTION

BRAF non-V600E mutations occur in 1% to 2% of NSCLCs. Because of their rarity, the clinical backgrounds and outcomes of cytotoxic chemotherapy or immunotherapy remain unclear, and no targeted therapies are approved for BRAF non-V600E-mutant NSCLC.

METHODS

In this multi-institutional prospective lung cancer genomic screening project (LC-SCRUM-Asia), we evaluated the clinicogenomic characteristics and therapeutic outcomes of BRAF non-V600E-mutant NSCLC.

RESULTS

From March 2015 to November 2021, a total of 11,929 patients with NSCLC were enrolled. BRAF mutations were detected in 380 (3.5%), including the V600E (class I) in 119 (31%) and non-V600E in 261; the non-V600E were functionally classified into class II (122, 32%), class III (86, 23%), and non-classes I to III. Smokers and having concurrent RAS gene family or TP53 mutations were more frequently associated with class II or III than with class I. In patients with class III as compared with class I, the progression-free survival in response to platinum-containing chemotherapies (median, 5.3 versus 11.5 mo, p < 0.01) and the overall survival (median, 14.5 versus 34.8 mo, p < 0.02) were significantly shorter. Furthermore, class IIa mutations were significantly more frequent in our Asian cohort than in previously reported cohorts. The clinicogenomic features associated with class IIa were similar to those associated with class I, and one patient with NSCLC with K601E had a good response to dabrafenib plus trametinib.

CONCLUSIONS

Patients with NSCLCs with BRAF non-V600E, especially class III, were associated with poorer therapeutic outcomes than those with V600E. Furthermore, patients with NSCLC with class IIa had distinct clinicogenomic features, and further preclinical and clinical studies are needed to evaluate class IIa mutations as a therapeutic target.

Metastatic Small Bowel Adenocarcinoma Mimicking a Primary Ovarian Mucinous Tumour - Clinical, Radiologic, Pathologic and Molecular Correlation

We describe an interesting case of a patient who presented with a large adnexal mass, first favored to be mucinous carcinoma of the gynecologic origin. The primary tumour site was ascertained after the patient's small bowel was resected by identifying an adenomatous component evolving into an invasive adenocarcinoma identical in morphology and immunophenotype to the ovarian tumour. Notably, both tumours were found to harbor a BRAF K601E mutation, which is extremely rare for a primary of the ovary. BRAF mutations are present in a subset of large bowel and small bowel adenocarcinoma, but our case shows the first instance of a BRAF K601E mutation being present in a small bowel adenocarcinoma, to the best of our knowledge. This case serves as a great illustration of the pivotal role of molecular diagnostics in modern pathology in arriving at the correct diagnosis. Additionally, it is an excellent example of how clinical-radiologic-pathologic-molecular correlation plays into the landscape of molecular pathology to deliver optimal care for the patient.

Non-small-cell lung cancer: how to manage BRAF-mutated disease

BRAF mutations are reported in about 3-5% of non-small-cell lung cancer (NSCLC), almost exclusively in adenocarcinoma histology, and are classified into three different classes. The segmentation of BRAF mutations into V600 (class 1) and non-V600 (classes 2 and 3) relies on their biological characteristics and is of interest for predicting the therapeutic benefit of targeted therapies and immunotherapy. Given the relative rarity of this molecular subset of disease, evidence supporting treatment choices is limited. This review aims to offer a comprehensive update about available therapeutic options for patients with NSCLC harbouring BRAF mutations to guide the physician in the choice of treatment strategies. We collected the most relevant available data, from single-arm phase II studies and retrospective analyses conducted in advanced NSCLC, regarding the efficacy of BRAF and MEK inhibitors in both V600 and non-V600 BRAF mutations. We included case reports and smaller experiences that could provide information on specific alterations. With respect to immunotherapy, we reviewed retrospective evidence on immune-checkpoint inhibitors in this molecular subset, whereas data about chemo-immunotherapy in this molecular subgroup are lacking. Moreover, we included the available, though limited, retrospective evidence of immunotherapy as consolidation after chemo-radiation for unresectable stage III BRAF-mutant NSCLC, and an overview of ongoing clinical trials in the peri-operative setting that could open new perspectives in the future.

Cobimetinib Plus Vemurafenib in Patients With Colorectal Cancer With BRAF Mutations: Results From the Targeted Agent and Profiling Utilization Registry (TAPUR) Study

PURPOSE

TAPUR is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. The results of a cohort of patients with colorectal cancer (CRC) with BRAF mutations treated with cobimetinib (C) plus vemurafenib (V) are reported.

METHODS

Eligible patients had advanced CRC, no standard treatment options, measurable disease (RECIST), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, tumors with BRAF V600E/D/K/R mutations, and no MAP2K1/2, MEK1/2, or NRAS mutations. C was taken 60 mg orally once daily for 21 days followed by seven days off, and V was taken 960 mg orally twice daily. Simon's two-stage design was used with a primary study end point of objective response or stable disease of at least 16 weeks duration. Secondary end points were progression-free survival, overall survival, and safety.

RESULTS

Thirty patients were enrolled from August 2016 to August 2018; all had CRC with a BRAF V600E mutation except one patient with a BRAF K601E mutation. Three patients were not evaluable for efficacy. Eight patients with partial responses and six patients with stable disease of at least 16 weeks duration were observed for disease control and objective response rates of 52% (95% CI, 35 to 65) and 30% (95% CI, 14 to 50), respectively. The null hypothesis of 15% disease control rate was rejected ( P < .0001). Thirteen patients had at least one grade 3 adverse event or serious adverse event at least possibly related to C + V: anemia, decreased lymphocytes, dyspnea, diarrhea, elevated liver enzymes, fatigue, hypercalcemia, hypophosphatemia, rash, photosensitivity, and upper gastrointestinal hemorrhage.

CONCLUSION

The combination of C + V has antitumor activity in heavily pretreated patients with CRC with BRAF mutations.

Unusual Clinical Experience in BRAF Exon 15 p.K601E-Mutated Lung Cancer: A Case Report and Brief Review of the Literature

Molecular profiling has revolutionized the treatment of metastatic NSCLC. Uncommon mutations have been reported primarily in EGFR and BRAF genes and are frequently associated with atypical clinical presentations. Here, we present a rare case of a patient affected by BRAF exon 15 p.K601E-mutated lung cancer with synchronous peritoneal carcinomatosis. First line treatment with chemo-immunotherapy combinations provided a PFS of 8–9 months, whereas a second line treatment with BRAF and MEK inhibitors elicited a dissociated response. The latter clinical outcome suggests that these inhibitors have only partial activity against this rare mutation.

Durable Response to Combined Dabrafenib and Trametinib in a Patient With BRAF K601E Mutation-Positive Lung Adenocarcinoma: A Case Report

Targeted therapy with combined dabrafenib and trametinib has been proven to provide clinical benefits in patients with NSCLC with a BRAF V600E mutation. Nevertheless, the treatment strategy for patients with NSCLC with BRAF non-V600E mutations remains limited. Here, we present a patient with NSCLC with a BRAF K601E mutation, a class II BRAF mutation, who had a durable response to targeted therapy with combined dabrafenib and trametinib.