Background

Interventional pulmonologists (IPs) are often the first specialist to see patients with suspected metastatic non-small cell lung cancer (mNSCLC). Consequently, they are potentially ideally positioned to expedite the identification of actionable molecular mutations by ordering blood-based cell-free DNA (cfDNA), prior to or upon tissue diagnosis of mNSCLC.

Methods

Retrospective review of cfDNA ordered by IP as part of a routine clinical practice. Patients were categorized into two groups based on when cfDNA was ordered by IP: (1) IP suspected mNSCLC prior to histologic confirmation or (2) IP diagnosed mNSCLC based on histologic confirmation of NSCLC.

Results

Twenty patients were identified. Twelve of 13 in group 1 were confirmed to have mNSCLC by oncology and 1 had stage IIIA. Seven of 7 in group 2 were confirmed to have mNSCLC by oncology. Fifteen of 20 also had next-generation tissue molecular testing. Thirteen of 20 (65%) had targetable alterations. Seven of 13 (54%) were identified on cfDNA and tissue, 5/13 (38%) on cfDNA only, and 1/13 (8%) on tissue alone. Tissue results were available a medium of 24 days after, and cfDNA results a medium of 4 days prior to, the patients' first oncology visit.

Conclusions

IP appears to be able identify patients who have mNSCLC and for whom testing for molecular mutations is appropriate even prior to tissue confirmation of NSCLC. A strategy whereby IP employ blood-based cfDNA testing in suspected and tissue confirmed mNSCLC could potentially provide medical oncologists with more timely information on actionable mutations than tissue-based testing first, potentially expediting patient treatment.

Background

Onalespib is a novel heat shock protein 90 inhibitor (HSP90i). Previous preclinical and clinical studies with HSP90i have demonstrated activity in EGFR-mutant non-small cell lung cancer (NSCLC). This study sought to determine the safety and tolerability of onalespib plus erlotinib in EGFR-mutant NSCLC and to evaluate the preliminary efficacy of the combination in epidermal growth factor receptor exon 20 insertion (EGFRex20ins) NSCLC.

Patients and methods

Standard 3+3 dose escalation was followed by a phase II expansion in EGFRex20ins. The phase II component targeted a response rate of 25% versus a background rate of 5%. Prospective next-generation sequencing (NGS) of 70 cancer-related genes, including EGFR, via plasma circulating tumor DNA (ctDNA) was performed. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE), version 4, and response was determined by Response Evaluation Criteria in Solid Tumours (RECIST) 1.1.

Results

Eleven patients were treated (nine dose escalation, two dose expansion). Two dose-limiting toxicities (DLTs) occurred in dose level (DL) 0 and zero in DL -1 (minus). In 10 EGFRex20ins patients, no responses were observed, median progression-free survival was 5.4 months (95% confidence interval, 0.9-5.7), and the disease control rate (DCR) was 40% (median, 3.5 months). EGFRex20ins was detected in nine of 10 ctDNA samples at baseline; on-treatment ctDNA clearance was not observed. Grade 3 diarrhea was the predominant toxicity in 45% of patients. The recommended phase II dose is DL -1 (minus): erlotinib 150 mg orally every morning and onalespib 120 mg/m² intravenously on days 1, 8, and 15 every 28 days.

Conclusion

Overlapping toxicities of erlotinib and onalespib, mainly diarrhea, limited the tolerability of this combination, and limited clinical activity was observed, so the trial was closed early. Plasma EGFRex20ins ctDNA was detected in the majority of patients; failure to clear ctDNA was consistent with lack of tumor response (NCT02535338).