Therapeutic drug monitoring of osimertinib in EGFR mutant non-small cell lung cancer by dried blood spot and plasma collection: A pilot study.

AIMS: Therapeutic drug monitoring (TDM) has led to significant improvements in individualized medical care, although its implementation in oncology has been limited to date. Tyrosine kinase inhibitors (TKIs) are a group of therapies for which TDM has been suggested. Osimertinib is one such therapy used in the treatment of epidermal growth factor receptor (EGFR) mutation-driven lung cancer. Herein, we describe a prospective pilot study involving 21 patients on osimertinib primarily as a preliminary evaluation of drug levels in a real-world setting. METHODS: Concentrations of the drug and its primary metabolites were measured with a validated liquid chromatography-mass spectrometry (LC-MS) assay across serial timepoints. As part of this study, inter-individual variability by dose and ethnicity as well as intra-individual variability across timepoints are explored. Furthermore, we attempted to validate dried blood spot (DBS)-based quantitation as an accurate alternative to plasma quantitation. RESULTS: Successful quantitation of osimertinib and primary metabolites was achieved for our subjects. Compound plasma levels were highly correlated to DBS levels. There was no significant difference in concentrations with ethnicity or dosing or intra-individual variability across timepoints. CONCLUSIONS: As such, we demonstrate that TDM for osimertinib is practical for future trials. We also validated the use of DBS as an alternative to conventional quantitation for exploration of TDM for osimertinib in larger trials and for other targeted therapies.

Completion of Pembrolizumab in Advanced Non-Small Cell Lung Cancer-Real World Outcomes After Two Years of Therapy (COPILOT).

BACKGROUND: Seminal trials with first-line pembrolizumab for metastatic non-small cell lung cancer (NSCLC) mandated a maximum two-years treatment. We describe real-world outcomes of a multi-site Australian cohort of patients who completed two-years of pembrolizumab. METHODS: Retrospective data were collected from the national AUstralian Registry and biObank of thoRacic cAncers (AURORA). Primary endpoints were progression rate post pembrolizumab discontinuation; and progression free survival (PFS). Local treatment of oligoprogressive disease during pembrolizumab was allowed. RESULTS: A total of 71 patients from six centers, median age 66.0 years, 49% male and 90% ECOG ≤ 1 were identified. Patients were Caucasian (82%) or Asian (16%); past (66%) or current (24%) smokers with mean 37 pack-years. Histology comprised 73% adenocarcinoma and 16% squamous. 18 patients (25%) had brain metastases at diagnosis. Median PD-L1 tumor proportion score (TPS) was 68%; 12 patients (17%) TPS < 1% and 43 (61%) TPS ≥ 50%. No patients had EGFR/ALK/ROS1 alterations; 29/49 tested (60%) had KRAS mutations. Median follow up was 38.7 months. Objective response rate 78.6%. Median PFS 46.1 months (95% CI 39.5-NR), not reached (46.1-NR) in PD-L1 TPS ≥ 1% versus 28.1 months (16.3-NR) in TPS < 1% (P = .013). 17 patients (24%) received additional local therapy for oligoprogression. Post pembrolizumab discontinuation, 20 patients (28%) had disease progression. Higher rates of progression occurred with TPS < 1% (OR 3.46, P = .06), without complete response (OR 5.06, P = .04), and with treated oligoprogression (OR 3.11, P = .05). 36-month landmark survival was 98.2%. CONCLUSION: Patients completing two-years of pembrolizumab for NSCLC in an Australian cohort had high rates of KRAS mutation and PD-L1 expression; a proportion had brain metastases and treated oligoprogression. Progression post pembrolizumab was higher in PD-L1 TPS < 1% and in those without complete response.

Mobocertinib in Patients with EGFR Exon 20 Insertion-Positive Non-Small Cell Lung Cancer (MOON): An International Real-World Safety and Efficacy Analysis.

EGFR exon 20 (EGFR Ex20) insertion mutations in non-small cell lung cancer (NSCLC) are insensitive to traditional EGFR tyrosine kinase inhibitors (TKIs). Mobocertinib is the only approved TKI specifically designed to target EGFR Ex20. We performed an international, real-world safety and efficacy analysis on patients with EGFR Ex20-positive NSCLC enrolled in a mobocertinib early access program. We explored the mechanisms of resistance by analyzing postprogression biopsies, as well as cross-resistance to amivantamab. Data from 86 patients with a median age of 67 years and a median of two prior lines of treatment were analyzed. Treatment-related adverse events (TRAEs) occurred in 95% of patients. Grade ≥3 TRAEs were reported in 38% of patients and included diarrhea (22%) and rash (8%). In 17% of patients, therapy was permanently discontinued, and two patients died due to TRAEs. Women were seven times more likely to discontinue treatment than men. In the overall cohort, the objective response rate to mobocertinib was 34% (95% CI, 24-45). The response rate in treatment-naïve patients was 27% (95% CI, 8-58). The median progression-free and overall survival was 5 months (95% CI, 3.5-6.5) and 12 months (95% CI, 6.8-17.2), respectively. The intracranial response rate was limited (13%), and one-third of disease progression cases involved the brain. Mobocertinib also showed antitumor activity following EGFR Ex20-specific therapy and vice versa. Potential mechanisms of resistance to mobocertinib included amplifications in MET, PIK3CA, and NRAS. Mobocertinib demonstrated meaningful efficacy in a real-world setting but was associated with considerable gastrointestinal and cutaneous toxicity.

First-line chemoimmunotherapy and immunotherapy in patients with non-small cell lung cancer and brain metastases: a registry study.

Introduction: Brain metastases commonly occur in patients with non-small cell lung cancer (NSCLC). Standard first-line treatment for NSCLC, without an EGFR, ALK or ROS1 mutation, is either chemoimmunotherapy or anti-PD-1 monotherapy. Traditionally, patients with symptomatic or untreated brain metastases were excluded from the pivotal clinical trials that established first-line treatment recommendations. The intracranial effectiveness of these treatment protocols has only recently been elucidated in small-scale prospective trials. Methods: Patients with NSCLC and brain metastases, treated with first-line chemoimmunotherapy or anti-PD-1 monotherapy were selected from the Australian Registry and biObank of thoracic cancers (AURORA) clinical database covering seven institutions. The primary outcome was a composite time-to-event (TTE) outcome, including extracranial and intracranial progression, death, or need for local intracranial therapy, which served as a surrogate for disease progression. The secondary outcome included overall survival (OS), intracranial objective response rate (iORR) and objective response rate (ORR). Results: 116 patients were included. 63% received combination chemoimmunotherapy and 37% received anti-PD-1 monotherapy. 69% of patients received upfront local therapy either with surgery, radiotherapy or both. The median TTE was 7.1 months (95% CI 5 - 9) with extracranial progression being the most common progression event. Neither type of systemic therapy or upfront local therapy were predictive of TTE in a multivariate analysis. The median OS was 17 months (95% CI 13-27). Treatment with chemoimmunotherapy was predictive of longer OS in multivariate analysis (HR 0.35; 95% CI 0.14 - 0.86; p=0.01). The iORR was 46.6%. The iORR was higher in patients treated with chemoimmunotherapy compared to immunotherapy (58% versus 31%, p=0.01). The use of chemoimmunotherapy being predictive of iORR in a multivariate analysis (OR 2.88; 95% CI 1.68 - 9.98; p=0.04). Conclusion: The results of this study of real-world data demonstrate the promising intracranial efficacy of chemoimmunotherapy in the first-line setting, potentially surpassing that of immunotherapy alone. No demonstrable difference in survival or TTE was seen between receipt of upfront local therapy. Prospective studies are required to assist clinical decision making regarding optimal sequencing of local and systemic therapies.

Lurbinectedin in small cell lung cancer: real-world experience of a multicentre national early access programme.

BACKGROUND AND AIMS: Lurbinectedin is a novel oncogenic transcription inhibitor active in several cancers, including small cell lung cancer (SCLC). We aimed to describe the first Australian experience of the clinical efficacy and tolerability of lurbinectedin for the treatment of SCLC after progression on platinum-containing therapy. METHODS: Multicentre real-world study of individuals with SCLC initiating lurbinectedin monotherapy (3.2 mg/m2 three-weekly) on an early access programme between May 2020 and December 2021. Key outcomes were clinical utilisation, efficacy and tolerability. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Outcome data were collected within the AUstralian Registry and biObank of thoRacic cAncers (AURORA). RESULTS: Data were analysed for 46 individuals across seven sites. Lurbinectedin was given as second- (83%, 38/46) or subsequent- (17%, 8/46) line therapy, mostly with prior chemoimmunotherapy (87%, 40/46). We report dose modifications (17%, 8/46), interruptions/delays (24%, 11/46), high-grade toxicities (28%, 13/46) and hospitalisations (54%, 25/46) during active treatment. The overall response rate was 33% and the disease control rate was 50%. Six-month OS was 44% (95% confidence interval (CI): 29.0-57.1). Twelve-month OS was 15% (95% CI: 6.5-26.8). From lurbinectedin first dose, the median PFS was 2.5 months (95% CI: 1.8-2.9) and OS was 4.5 months (95% CI: 3.5-7.2). From SCLC diagnosis, the median OS was 12.9 months (95% CI: 11.0-17.2). Individuals with a longer chemotherapy-free interval prior to lurbinectedin had longer PFS and OS. CONCLUSION: This real-world national experience of lurbinectedin post-platinum chemotherapy and immunotherapy for individuals with SCLC was similar to that reported in clinical trials.

A Validated Assay to Quantify Osimertinib and Its Metabolites, AZ5104 and AZ7550, from Microsampled Dried Blood Spots and Plasma.

BACKGROUND: Osimertinib is an oral small-molecule tyrosine kinase receptor inhibitor used to treat non-small cell lung cancer (NSCLC) with a sensitizing epidermal growth factor receptor mutation. Patients may experience drug toxicity and require dose deescalation. The study aimed to quantitate osimertinib and its 2 active metabolites, AZ5104 and AZ7550, in microsampled dried blood spots (DBS) collected from patients with NSCLC using a hemaPEN device and compare them with plasma drug levels. METHODS: A 6-min ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated using plasma and DBS. The accuracy, selectivity, matrix effect, recovery, and stability were assessed using bioanalytical validation criteria. The hematocrit effect was investigated in DBS. Drug levels were measured in 15 patients with NSCLC, and the Bland-Altman method was used to compare measurements between plasma and DBS. RESULTS: The validated assay determined accurate and precise quantities, respectively, for osimertinib in both plasma (93.2%-99.3%; 0.2%-2.3%) and DBS (96.7%-99.6%; 0.5%-10.3%) over a concentration of 1-729 ng/mL. The osimertinib metabolites, AZ5104 and AZ7550, were similarly validated in accordance with bioanalytical guidelines. For 30%-60% patient hematocrit, no hematocrit bias was observed with DBS for all analytes. The Bland-Altman method showed high concordance between plasma and DBS analyte levels. Stability experiments revealed that osimertinib and its metabolites were poorly stable in plasma at room temperature, whereas all analytes were stable in DBS for 10 days at room temperature. CONCLUSIONS: The measurement of osimertinib, AZ5104, and AZ7550 from hemaPEN microsampled DBS is a convenient and reliable approach for therapeutic drug monitoring that produces measurements consistent with plasma drug levels.