Encouragement to submit data of clinical response to EGFR-TKIs in patients with uncommon EGFR mutations

Efficacy of immune checkpoint blockade in MUTYH-associated hereditary colorectal cancer

Colorectal carcinomas (CRCs) caused by hereditary biallelic MUTYH gene mutations are characterized by elevated mutation load and high lymphocyte infiltration. Given that these tumor features are associated with the response to immune checkpoint inhibitors, we administered nivolumab to a CRC patient who carried two inactive MUTYH alleles (p.Y179C and p.G396D) and previously experienced failure of chemotherapy. This experimental treatment resulted in a pronounced tumor response. We further compared tumor lymphocyte infiltration in MUTYH-associated (n = 3), high-level microsatellite instability (MSI-H, n = 8) and microsatellite stable (MSS, n = 6) CRCs. Both MUTYH-driven and MSI-H CRCs showed noticeably higher lymphocyte densities than those of microsatellite stable tumors; this difference reached the level of statistical significance for the comparison of central areas of the tumors (p = 0.02 and 0.03, respectively) but not for the invasive tumor margins. Although MUTYH-associated tumors are exceptionally rare among unselected CRC cases, their share in CRC patients with somatic KRAS p.G12C substitution approaches 5-25%. These observations provide a rationale for further evaluation of the efficacy of the immune checkpoint blockade in MUTYH-driven CRC.

Brain metastasis in non-small cell lung cancer (NSCLC) patients with uncommon EGFR mutations: a report of seven cases and literature review

Brain metastasis (BM) arising from non-small cell lung cancer (NSCLC) with rare epidermal growth factor receptor (EGFR) mutations is quite rare. The prognosis and therapeutic effects of BM remain enigmatic. To the best of our knowledge, this is the first report to make a separate analysis of BM from NSCLC patients with original uncommon EGFR mutations. We retrospectively reviewed 7 cases of BM arising from 42 cases of uncommon EGFR mutated lung cancer in Tianjin Medical University Cancer Institute and Hospital. We also performed a literature review to assess therapeutic features and outcomes.

Efficacy analysis of tyrosine kinase inhibitors on rare non-small cell lung cancer patients harboring complex EGFR mutations

The efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) in patients with non-small cell lung cancer (NSCLC) is related to EGFR mutations. Although the p.L858R point mutation in exon 21 and the in-frame deletion mutation in exon 19 are well known, efficacy of EGFR-TKI in patients with more than one EGFR mutation is not well understood. 799 NSCLC patients were screened for EGFR mutations. Of the 799 patients, 443 (55.4%) had mutations, out of which 22 (2.75%) had multiple complex mutations. Most multiple mutations (20/22) harbored common mutations such as the p.L858R point mutation in exon 21 and the in-frame deletion mutation in exon 19. 11 out of 22 patients who had multiple EGFR mutations underwent TKI therapy and primary end-points of progression free and overall survival were determined. Our analysis revealed that cases with multiple mutations had similar end-point outcomes as single mutation to TKI therapy. Report of these cases will be helpful in decision making for treatment of NSCLC patients harboring multiple EGFR mutations.

Rare EGFR exon 18 and exon 20 mutations in non-small-cell lung cancer on 10 117 patients: a multicentre observational study by the French ERMETIC-IFCT network

BACKGROUND

There is scarce data available about epidermal growth factor receptor (EGFR) mutations other than common exon 19 deletions and exon 21 (L858R) mutations.

PATIENTS AND METHODS

EGFR exon 18 and/or exon 20 mutations were collected from 10 117 non-small-cell lung cancer (NSCLC) samples analysed at 15 French National Cancer Institute (INCa)-platforms of the ERMETIC-IFCT network.

RESULTS

Between 2008 and 2011, 1047 (10%) samples were EGFR-mutated, 102 (10%) with rare mutations: 41 (4%) in exon 18, 49 (5%) in exon 20, and 12 (1%) with other EGFR mutations. Exon 20 mutations were related to never-smoker status, when compared with exon 18 mutations (P < 0.001). Median overall survival (OS) of metastatic disease was 21 months [95% confidence interval (CI) 12-24], worse in smokers than in non-smoker patients with exon 20 mutations (12 versus 21 months; hazard ratio [HR] for death 0.27, 95% CI 0.08-0.87, P = 0.03). Under EGFR-tyrosine kinase inhibitors (TKIs), median OS was 14 months (95% CI 6-21); disease control rate was better for complex mutations (6 of 7, 86%) than for single mutations (16 of 40, 40%) (P = 0.03).

CONCLUSIONS

Rare EGFR-mutated NSCLCs are heterogeneous, with resistance of distal exon 20 insertions and better sensitivity of exon 18 or complex mutations to EGFR-TKIs, probably requiring individual assessment.

Natural history and molecular characteristics of lung cancers harboring EGFR exon 20 insertions

INTRODUCTION

Exon 20 insertions are the third most common family of epidermal growth factor receptor (EGFR) mutations found in non-small-cell lung cancer (NSCLC). Little is known about cancers harboring these mutations aside from their lack of response to EGFR tyrosine kinase inhibitors, impairing the development of effective targeted therapies.

METHODS

NSCLC patients with EGFR genotyping were studied using a mechanism approved by the Institutional Review Board. Cancers with exon 20 insertions were indentified, sequences were characterized, and effectiveness of different treatment regimens was reviewed retrospectively. Clinical characteristics and survival were compared with cancers harboring common EGFR mutations and cancers with wild-type EGFR.

RESULTS

One thousand eighty-six patients underwent EGFR genotyping from 2004 to 2012. Twenty seven (2.5%) harbored exon 20 insertions, making up 9.2% of all cancers with documented EGFR mutations. Compared with wild-type cancers, those with exon 20 insertions were more commonly found in never-smokers and Asian patients. Insertion sequences were highly variable, with the most common variant (V769_D770insASV) making up only 22% of cases. Median survival of patients with exon 20 insertions was 16 months, similar to the survival of wild-type cancers and shorter than the survival of cancers with common EGFR mutations.

CONCLUSIONS

Patients with EGFR exon 20 insertions have similar clinical characteristics to those with common EGFR mutations but a poorer prognosis. The prevalence of this subset of NSCLC is similar to that of other genotype-defined subsets of lung adenocarcinoma (e.g. those with BRAF mutations, HER2 insertions, ROS1 rearrangements) and is a population of interest for trials of new targeted therapies.

Compound EGFR mutations and response to EGFR tyrosine kinase inhibitors

BACKGROUND

Non-small-cell lung cancers (NSCLCs) containing EGFR mutations are exquisitely sensitive to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). This is the case of the most common EGFR mutations affecting exon 18 (G719X), 19 (inframe deletions), and 21 (L858R and L861Q). However, the frequency of compound (i.e., double or complex) EGFR mutations-where an EGFR TKI sensitizing or other mutation is identified together with a mutation of unknown clinical significance-and their pattern of response/resistance to EGFR TKIs are less well described.

METHODS

We analyzed the EGFR mutation pattern of 79 cases of NSCLC harboring EGFR mutations and compiled the genotype-response data for patients with NSCLCs with compound EGFR mutations treated with EGFR TKIs.

RESULTS

Of the 79 EGFR-mutated tumors identified, 11 (14%) had compound mutations. Most involved the EGFR TKI-sensitizing G719X (n = 3, plus S768I or E709A), L858R (n = 4, plus L747V, R776H, T790M, or A871G), L861Q (n = 1, plus E709V), and delL747_T751 (n = 1, plus R776H). Eight patients received an EGFR TKI: three cases with G719X plus another mutation had partial responses (PRs) to erlotinib; of three cases with L858R plus another mutation, two displayed PRs and one (with EGFR-L858R+A871G) progressive disease (PD) to erlotinib; one NSCLC with EGFR-L861Q+E709A and one with delL747_T751+R776S had PRs to EGFR TKIs.

CONCLUSION

Compound EGFR mutations comprised 14% of all mutations identified during routine sequencing of exons 18-21 of EGFR in our cohort. Most patients with an EGFR TKI-sensitizing mutation (G719X, exon 19 deletion, L858R, and L861Q) in addition to an atypical mutation responded to EGFR TKIs. Reporting of the genotype-response pattern of NSCLCs with EGFR compound and other rare mutations, and the addition of this information to searchable databases, will be helpful to select the appropriate therapy for EGFR-mutated NSCLC.

Detection and characterization of classical and "uncommon" exon 19 Epidermal Growth Factor Receptor mutations in lung cancer by pyrosequencing

Background

The management of advanced stage non-small cell lung cancer is increasingly based on diagnostic and predictive analyses performed mostly on limited amounts of tumor tissue. The evaluation of Epidermal Growth Factor Receptor (EGFR) mutations have emerged as the strongest predictor of response to EGFR-tyrosine kinase inhibitors mainly in patients with adenocarcinoma. Several EGFR mutation detection techniques are available, having both sensitivity and specificity issues, being the Sanger sequencing technique the reference standard, with the limitation of a relatively high amount of mutated cells needed for the analysis.

Methods

A novel nucleotide dispensation order for pyrosequencing was established allowing the identification and characterization of EGFR mutation not definable with commercially and clinically approved kits, and validated in a consecutive series of 321 lung cancer patients (246 biopsies or cytology samples and 75 surgical specimens).

Results

61/321 (19%) mutated cases were detected, 17 (27.9%) in exon 21 and 44 (72.1%) in exon 19, these latter corresponding to 32/44 (72.7%) classical and 12/44 (27.3%) uncommon mutations. Furthermore, a novel, never reported, point mutation, was found, which determined a premature stop codon in the aminoacidic sequence that resulted in a truncated protein in the tyrosine kinase domain, thus impairing the inhibitory effect of specific therapy.

Conclusions

The novel dispensation order allows to detect and characterize both classical and uncommon EGFR mutations. Although several phase III studies in genotypically defined groups of patients are already available, further prospective studies assessing the role of uncommon EGFR mutations are warranted.

Genotyping and genomic profiling of non-small-cell lung cancer: implications for current and future therapies

Substantial advances have been made in understanding critical molecular and cellular mechanisms driving tumor initiation, maintenance, and progression in non-small-cell lung cancer (NSCLC). Over the last decade, these findings have led to the discovery of a variety of novel drug targets and the development of new treatment strategies. Already, the standard of care for patients with advanced-stage NSCLC is shifting from selecting therapy empirically based on a patient's clinicopathologic features to using biomarker-driven treatment algorithms based on the molecular profile of a patient's tumor. This approach is currently best exemplified by treating patients with NSCLC with first-line tyrosine kinase inhibitors when their cancers harbor gain-of-function hotspot mutations in the epidermal growth factor receptor (EGFR) gene or anaplastic lymphoma kinase (ALK) gene rearrangements. These genotype-based targeted therapies represent the first step toward personalizing NSCLC therapy. Recent technology advances in multiplex genotyping and high-throughput genomic profiling by next-generation sequencing technologies now offer the possibility of rapidly and comprehensively interrogating the cancer genome of individual patients from small tumor biopsies. This advance provides the basis for categorizing molecular-defined subsets of patients with NSCLC in whom a growing list of novel molecularly targeted therapeutics are clinically evaluable and additional novel drug targets can be discovered. Increasingly, practicing oncologists are facing the challenge of determining how to select, interpret, and apply these new genetic and genomic assays. This review summarizes the evolution, early success, current status, challenges, and opportunities for clinical application of genotyping and genomic tests in therapeutic decision making for NSCLC.

DNA-Mutation Inventory to Refine and Enhance Cancer Treatment (DIRECT): a catalog of clinically relevant cancer mutations to enable genome-directed anticancer therapy

PURPOSE

Tumor gene mutation status is becoming increasingly important in the treatment of patients with cancer. A comprehensive catalog of tumor gene-response outcomes from individual patients is needed, especially for actionable mutations and rare variants. We created a proof-of-principle database [DNA-mutation Inventory to Refine and Enhance Cancer Treatment (DIRECT)], starting with lung cancer-associated EGF receptor (EGFR) mutations, to provide a resource for clinicians to prioritize treatment decisions based on a patient's tumor mutations at the point of care.

METHODS

A systematic search of literature published between June 2005 and May 2011 was conducted through PubMed to identify patient-level, mutation-drug response in patients with non-small cell lung cancer (NSCLC) with EGFR mutant tumors. Minimum inclusion criteria included patient's EGFR mutation, corresponding treatment, and an associated radiographic outcome.

RESULTS

A total of 1,021 patients with 1,070 separate EGFR tyrosine kinase inhibitor therapy responses from 116 different publications were included. About 188 unique EGFR mutations occurring in 207 different combinations were identified: 149 different mutation combinations were associated with disease control and 42 were associated with disease progression. Four secondary mutations, in 16 different combinations, were associated with acquired resistance.

CONCLUSIONS

As tumor sequencing becomes more common in oncology, this comprehensive electronic catalog can enable genome-directed anticancer therapy. DIRECT will eventually encompass all tumor mutations associated with clinical outcomes on targeted therapies. Users can make specific queries at http://www.mycancergenome.org/about/direct to obtain clinically relevant data associated with various mutations.