Prevalence, Treatment Patterns, and Outcomes of Individuals with EGFR Positive Metastatic Non-Small Cell Lung Cancer in a Canadian Real-World Setting: A Comparison of Exon 19 Deletion, L858R, and Exon 20 Insertion EGFR Mutation Carriers

Round 1

Reviewer 1 Report

In this registry-based study by Dylan E. O’Sullivan et al., the authors sought to collect epidemiological data regarding EGFR mutation status from patients with stages IIIB/IV NSCLC, as well as the characteristics, treatment patterns, and outcomes of individuals with Exon 19, L858R and Exon20ins mutations. The findings of this study are clinically useful to understand how patients with different EGFR mutations respond to various treatments.

In general, the content of the manuscript is well written but some minor revisions are needed.

Introduction Section:

Line 38-39: “The epidermal growth factor receptor (EGFR) is involved in cellular processes….which contribute to tumor growth.” Please specify how EGFR is associated with cancer progression.

Line 41: “More than 60% of NSCLCs express EGFR,…” Please clarify the meaning of expression.

Line 55: You can include the newest information about the treatment of NSCLC patients with Exon20ins.

Materials and Methods Section:

I would recommend to include data on mutation analysis methods used e.g. Sequencing-based methods and PCR-based methods. Smoking status could be also included for analysis.

I would also recommend to use Italics for gene names and non-italicized letters for the encoded protein.

Results Section:

Are data on the status of other somatic mutations available? If not, what was the reason (e.g. tissue depletion etc)?

Author Response

Reviewer Response curroncol-1876861

We want to thank the reviewers for the thoughtful comments, which have allowed us to improve the quality of our manuscript. On behalf of my co-authors, we are enthusiastic about the opportunity to revise and resubmit our manuscript “Prevalence, Treatment Patterns, and Outcomes of Individuals with EGFR Positive Metastatic Non-Small Cell Lung Cancer in a Canadian Real-World Setting: A Comparison of Exon 19 Deletion, L858R, and Exon 20 Insertion EGFRMutation Carriers” for consideration as an original article in Current Oncology.

Below we have provided our point-by-point responses to the reviewer comments, as well as a summary of changes/modifications in the revised version of our manuscript.

Reviewer 1

Comment 1: In this registry-based study by Dylan E. O’Sullivan et al., the authors sought to collect epidemiological data regarding EGFR mutation status from patients with stages IIIB/IV NSCLC, as well as the characteristics, treatment patterns, and outcomes of individuals with Exon 19, L858R and Exon20ins mutations. The findings of this study are clinically useful to understand how patients with different EGFR mutations respond to various treatments. In general, the content of the manuscript is well written but some minor revisions are needed.

Response 1: We thank the reviewer for the positive review of our manuscript.

Comment 2: Line 38-39: “The epidermal growth factor receptor (EGFR) is involved in cellular processes….which contribute to tumor growth.” Please specify how EGFR is associated with cancer progression.

Response 2: We have added how EGFR is associated with cancer progression:

“The epidermal growth factor receptor (EGFR) is involved in the regulation of both cell proliferation and apoptosis via signal transduction pathways. The dysregulation of EGFR can lead to uncontrolled cell proliferation, angiogenesis, and migration, which contribute to tumour growth and spread, and therefore presents as an important therapeutic target.”

Comment 3: Line 41: “More than 60% of NSCLCs express EGFR,…” Please clarify the meaning of expression.

Response 3: We have clarified the meaning of expression to be overexpression of EGFR:

“More than 60% of NSCLCs have been identified to have overexpression of EGFR, and in Canada EGFR mutations are identified in approximately 15% of all lung cancer cases”

Comment 4: Line 55: You can include the newest information about the treatment of NSCLC patients with Exon20ins.

Response 4: In the discussion section we mention therapies that have been prescribed for Exon20ins patients in other real-world studies. We also note that novel EGFR targeted therapies, such as amivantamab and mobocertinibin are anticipated to be used in the near future in Canada.

In the introduction section we have added the following:

“NSCLC patients with EGFR Exon20ins have been the target for several ongoing clinical trials”. We have also included a reference to a review paper that discusses emerging therapies and ongoing clinical trials for NSCLC patients with EGFR Exon20ins (PMID: 35418149).

Comment 5: I would recommend to include data on mutation analysis methods used e.g. Sequencing-based methods and PCR-based methods. Smoking status could be also included for analysis.

Response 5: EGFR mutation testing was completed with either PCR (Qiagen kit) or next-generation sequencing (Agena MassArray kit). We have included the types of mutation analysis in the methods section. Unfortunately, smoking status is not captured in the administrative databases utilized for this study. We have highlighted this lack of data as a limitation in the discussion section.

Comment 6: I would also recommend to use Italics for gene names and non-italicized letters for the encoded protein.

Response 6: We have edited the text to include italics for gene names and non-italicized letters for the encoded proteins.

Comment 7: Are data on the status of other somatic mutations available? If not, what was the reason (e.g. tissue depletion etc)?

Response 7: Data on other somatic mutations were available, but the focus of this study was to compare exon20ins to the most common EGFR mutations, therefore analyses of somatic mutations within other genes were not investigated. While not included in the main analysis of this paper, we have added an overview of the prevalence of other types of EGFR mutations at the beginning of the results section:

Among individuals who underwent EGFR testing between 2013 and 2019 and who had adequate DNA (n=2,974), 451 (15.2%) were EGFR positive. Out of the 451 patients with a detected EGFR mutation, 221 (49%) had an Exon19 mutation, 159 (35.3%) had an L858R mutation, 18 (4.0%) had an Exon20ins mutation, 31 (6.9%) had an Exon18 mutation, 19 (4.2%) had an Exon20del mutation, 14 (3.1%) had an L861Q mutation, and 3 (0.7%) had an EGFR mutation of uncertain location (note: 14 of the 451 (3.1%) individuals with EGFR mutations had two mutations; there were no instances of individuals simultaneously having any combination of Exon20ins, L858R, or Exon19, which are the focus of subsequent analyses).

Reviewer 2 Report

Submitted manuscript titled “Prevalence, Treatment Patterns, and Outcomes of Individuals 2 with EGFR Positive Metastatic Non-Small Cell Lung Cancer in 3 a Canadian Real-World Setting: A Comparison of Exon 19 Dele-4 tion, L858R, and Exon 20 Insertion EGFR Mutation Carriers”, by O’Sullivan et al investigated the prevalence, treatment patterns, and outcomes of EGFR positive lung cancer. The article was generally well written, there are some clinically important findings.

1.     Author said that author used PCR testing, but are there any patients who have used other tests? (NGS, sanger?). Please add the specific PCR technique used in the Methods section.

2.     Please add specific cell types other than adenocarcinoma in EGFR positive patients

3.     In addition to Exon19, L858R and Exon20ins, how many patients have rare mutations (eg, exon 18 mutation)?

4.     Please add which statistical program you used.

5.     Have all EGFR tests been performed on biopsy samples? Has anyone tested with surgical specimens?

Author Response

Reviewer Response curroncol-1876861

We want to thank the reviewers for the thoughtful comments, which have allowed us to improve the quality of our manuscript. On behalf of my co-authors, we are enthusiastic about the opportunity to revise and resubmit our manuscript “Prevalence, Treatment Patterns, and Outcomes of Individuals with EGFR Positive Metastatic Non-Small Cell Lung Cancer in a Canadian Real-World Setting: A Comparison of Exon 19 Deletion, L858R, and Exon 20 Insertion EGFRMutation Carriers” for consideration as an original article in Current Oncology.

Below we have provided our point-by-point responses to the reviewer comments, as well as a summary of changes/modifications in the revised version of our manuscript.

Reviewer 2

Comment 1: Submitted manuscript titled “Prevalence, Treatment Patterns, and Outcomes of Individuals 2 with EGFR Positive Metastatic Non-Small Cell Lung Cancer in 3 a Canadian Real-World Setting: A Comparison of Exon 19 Dele-4 tion, L858R, and Exon 20 Insertion EGFR Mutation Carriers”, by O’Sullivan et al investigated the prevalence, treatment patterns, and outcomes of EGFR positive lung cancer. The article was generally well written, there are some clinically important findings.

Response 1: We thank the reviewer for the positive review of our manuscript.

Comment 2: Author said that author used PCR testing, but are there any patients who have used other tests? (NGS, sanger?). Please add the specific PCR technique used in the Methods section.

Response 2: EGFR mutation testing was completed with either PCR (Qiagen kit) or next-generation sequencing (Agena MassArray kit). We have added the specific mutation analyses to the methods section.

Comment 3: Please add specific cell types other than adenocarcinoma in EGFR positive patients

Response 3: As noted on page 4 (line 139), 5% of EGFR positive patients had unknown morphology and 2% had a morphology other than adenocarcinoma. Due to privacy regulations we cannot provide specific morphologies within the “other” category since all the specific morphologies have cell counts < 10.

Comment 4: In addition to Exon19, L858R and Exon20ins, how many patients have rare mutations (eg, exon 18 mutation)?

Response 4: Data on other rare EGFR mutations were available. However, the focus of this study was to compare exon20ins to the two most common EGFR mutations (Exon19 and L858R), therefore other EGFR mutations were not included in the main analyses. In response to this comment we have added the prevalence of other EGFR mutations to the start of the results section:

Among individuals who underwent EGFR testing between 2013 and 2019 and who had adequate DNA (n=2,974), 451 (15.2%) were EGFR positive. Out of the 451 patients with a detected EGFR mutation, 221 (49%) had an Exon19 mutation, 159 (35.3%) had an L858R mutation, 18 (4.0%) had an Exon20ins mutation, 31 (6.9%) had an Exon18 mutation, 19 (4.2%) had an Exon20del mutation, 14 (3.1%) had an L861Q mutation, and 3 (0.7%) had an EGFR mutation of uncertain location (note: 14 of the 451 (3.1%) individuals with EGFR mutations had two mutations; there were no instances of individuals simultaneously having any combination of Exon20ins, L858R, or Exon19, which are the focus of subsequent analyses).

Comment 5: Please add which statistical program you used.

Response 5: All statistical programing was completed with the R computing framework. We have added this to the methods.

Comment 6: Have all EGFR tests been performed on biopsy samples? Has anyone tested with surgical specimens?

Response 6: Information on the specimen source was not available in the database. However, the vast majority of EGFR testing would have been done on biopsy samples in this disease setting.

Round 2

Reviewer 2 Report

The authors responded appropriately to the peer review.

Author Response

We thank the reviewers for approving our revisions.