CNS Control after First-Line Osimertinib in Patients with Metastatic EGFR-Mutant NSCLC

PURPOSE/OBJECTIVE(S)

Although osimertinib (osi) has excellent intracranial activity in EGFR-mutant metastatic non-small cell lung cancer (NSCLC), there is no consensus regarding whether to continue osi for central nervous system (CNS) control with second-line chemotherapy (chemo) at the time of systemic progression. We aimed to compare CNS outcomes after first-line osi in patients receiving second-line chemo with or without continuation of osi.

MATERIALS/METHODS

We retrospectively reviewed patients with EGFR-mutant NSCLC with brain metastases (BrM) at the time of initiating first-line osi who experienced progression and started second-line chemo. Cumulative incidence of local and distant CNS progression, and extracranial (EC) progression was calculated from time of second-line chemo initiation with death as a competing risk. Overall survival (OS) was analyzed using Kaplan-Meier.

RESULTS

We included 52 patients with a median follow up of 9.6 months (range 0.4-36.4). Median OS and CNS progression-free survival (PFS) from the time of starting second-line chemo was 12.5 months (95% CI 8.1-16.9), and 5.3 months (95% CI 3.35-7.26), respectively. The 1-year cumulative incidence of local, distant CNS progression, any CNS progression, and EC progression was 14.4% (95% CI 4.5-24.2), 42.8% (95% CI 22.8-56.8), 42.8% (95% CI 22.8-56.8) and 66.8% (95% CI 53.5-80.2), respectively. After progression on first-line osi, 25 (48.1%) and 27 patients (51.9%) continued and discontinued osi, respectively. Patients who continued osi had significantly higher BrM burden than those who did not, with 17 (68%), 3 (12%), and 5 (20%) versus 26 (96%), 0, and 1 (3.7%) patient having <10 or >11 parenchymal brain lesions, or leptomeningeal disease (LMD) at the time of second line therapy, respectively (p<0.01). In those who continued osi vs those who did not, median OS (10.8 vs 12.5 months; p = 0.37), median intracranial PFS (5.3 vs 4.8 months; p = 0.99), 1-year cumulative incidence of local (8.4% versus 20 % p = 0.26), and 1-year distant CNS progression (24.8% vs 60%; p = 0.08) was not significantly different. CNS complications such as symptomatic, hospitalizations, and steroid initiation for CNS disease, and progression of LMD were not significantly different between the two groups. Eventually, 10 patients underwent salvage RT post first-line osi and median time to salvage RT was 7.8 months (range 2-9.4). Of patients who underwent salvage RT, 2 patients (20%) had continued osi with second-line chemo. Twelve patients (44.4%) who did not continue osi eventually re-started osi for progressive disease.

CONCLUSION

Patients who continued osi had significantly higher BrM tumor burden. Despite these patients being at higher risk for CNS progression, time to CNS progression and incidence of CNS complications were not significantly different in the two cohorts. Patients who discontinued osi were more likely to undergo salvage RT. Continuation of osi may allow patients to defer salvage RT.

Pharmacovigilance Analysis of Heart Failure Associated With Anti-HER2 Monotherapies and Combination Regimens for Cancer

Background

Trastuzumab improves outcomes in patients with HER2-overexpressing malignancies but is associated with decreases in left ventricular ejection fraction. Heart failure (HF) risks from other anti-HER2 therapies are less clear.

Objectives

Using World Health Organization pharmacovigilance data, the authors compared HF odds across anti-HER2 regimens.

Methods

In VigiBase, 41,976 patients had adverse drug reactions (ADRs) with anti-HER2 monoclonal antibodies (trastuzumab, n = 16,900; pertuzumab, n = 1,856), antibody-drug conjugates (trastuzumab emtansine [T-DM1], n = 3,983; trastuzumab deruxtecan, n = 947), and tyrosine kinase inhibitors (afatinib, n = 10,424; lapatinib, n = 5,704; neratinib, n = 1,507; tucatinib, n = 655); additionally, 36,052 patients had ADRs with anti-HER2-based combination regimens. Most patients had breast cancer (monotherapies, n = 17,281; combinations, n = 24,095). Outcomes included comparison of HF odds with each monotherapy relative to trastuzumab, within each therapeutic class, and among combination regimens.

Results

Of 16,900 patients with trastuzumab-associated ADRs, 2,034 (12.04%) had HF reports (median time to onset 5.67 months; IQR: 2.85-9.32 months) compared with 1% to 2% with antibody-drug conjugates. Trastuzumab had higher odds of HF reporting relative to other anti-HER2 therapies collectively in the overall cohort (reporting OR [ROR]: 17.37; 99% CI: 14.30-21.10) and breast cancer subgroup (ROR: 17.10; 99% CI: 13.12-22.27). Pertuzumab/T-DM1 had 3.4 times higher odds of HF reporting than T-DM1 monotherapy; tucatinib/trastuzumab/capecitabine had similar odds as tucatinib. Among metastatic breast cancer regimens, HF odds were highest with trastuzumab/pertuzumab/docetaxel (ROR: 1.42; 99% CI: 1.17-1.72) and lowest with lapatinib/capecitabine (ROR: 0.09; 99% CI: 0.04-0.23).

Conclusions

Trastuzumab and pertuzumab/T-DM1 had higher odds of HF reporting than other anti-HER2 therapies. These data provide large-scale, real-world insight into which HER2-targeted regimens would benefit from left ventricular ejection fraction monitoring.

Local control of brain metastases with osimertinib alone in patients with EGFR-mutant non-small cell lung cancer

PURPOSE

Although osimertinib has excellent intracranial activity in metastatic non-small cell lung cancer (NSCLC) with exon 19 deletion or L858R EGFR alterations, measures of local control of brain metastases are less well-reported. We describe lesion-level outcomes of brain metastases treated with osimertinib alone.

METHODS

We retrospectively reviewed patients with EGFR-mutant NSCLC with untreated brain metastasis measuring ≥ 5 mm at the time of initiating osimertinib. Cumulative incidence of local recurrence in brain (LRiB) was calculated with death as a competing risk, and univariable and multivariable analyses were conducted to identify factors associated with LRiB.

RESULTS

We included 284 brain metastases from 37 patients. Median follow-up was 20.1 months. On initial MRI after starting osimertinib, patient-level response was complete response (CR) in 11 (15%), partial response (PR) in 33 (45%), stable disease (SD) in 18 (25%) and progressive disease (PD) in 11 (15%). The 1-year cumulative incidence of LRiB was 14% (95% CI 9.9-17.9) and was significantly different in patients with a CR (0%), PR (4%), and SD (11%; p = 0.02). Uncontrolled primary tumor (adjusted hazard ratio [aHR] 3.78, 95% CI 1.87-7.66; p < 0.001), increasing number of prior systemic therapies (aHR 2.12, 95% CI 1.49-3.04; p < 0.001), and higher ECOG score (aHR 7.8, 95% CI 1.99-31.81; p = 0.003) were associated with LRiB.

CONCLUSIONS

Although 1-year cumulative incidence of LRiB is < 4% with a CR or PR, 1-year cumulative incidence of LRiB is over 10% for patients with less than a PR to osimertinib on initial MRI. These patients should be followed closely for need for additional treatment such as stereotactic radiosurgery.

Predictive Model to Guide Brain Magnetic Resonance Imaging Surveillance in Patients With Metastatic Lung Cancer: Impact on Real-World Outcomes

PURPOSE

Brain metastasis is common in lung cancer, and treatment of brain metastasis can lead to significant morbidity. Although early detection of brain metastasis may improve outcomes, there are no prediction models to identify high-risk patients for brain magnetic resonance imaging (MRI) surveillance. Our goal is to develop a machine learning-based clinicogenomic prediction model to estimate patient-level brain metastasis risk.

METHODS

A penalized regression competing risk model was developed using 330 patients diagnosed with lung cancer between January 2014 and June 2019 and followed through June 2021 at Stanford HealthCare. The main outcome was time from the diagnosis of distant metastatic disease to the development of brain metastasis, death, or censoring.

RESULTS

Among the 330 patients, 84 (25%) developed brain metastasis over 627 person-years, with a 1-year cumulative brain metastasis incidence of 10.2% (95% CI, 6.8 to 13.6). Features selected for model inclusion were histology, cancer stage, age at diagnosis, primary site, and RB1 and ALK alterations. The prediction model yielded high discrimination (area under the curve 0.75). When the cohort was stratified by risk using a 1-year risk threshold of > 14.2% (85th percentile), the high-risk group had increased 1-year cumulative incidence of brain metastasis versus the low-risk group (30.8% v 6.1%, P < .01). Of 48 high-risk patients, 24 developed brain metastasis, and of these, 12 patients had brain metastasis detected more than 7 months after last brain MRI. Patients who missed this 7-month window had larger brain metastases (58% v 33% largest diameter > 10 mm; odds ratio, 2.80, CI, 0.51 to 13) versus those who had MRIs more frequently.

CONCLUSION

The proposed model can identify high-risk patients, who may benefit from more intensive brain MRI surveillance to reduce morbidity of subsequent treatment through early detection.

Characterization of ERBB2 (HER2) Alterations in Metastatic Non-small Cell Lung Cancer and Comparison of Outcomes of Different Trastuzumab-based Regimens

INTRODUCTION

About 3%-5% of mNSCLC have ERBB2 (HER2) alterations, but currently, there are no FDA-approved targeted therapies for this indication. We compared treatment response between trastuzumab-based and non-targeted regimens in ERBB2-mutant mNSCLC.

METHODS

This retrospective, single-institution study included patients with mNSCLC with ERBB2 alterations identified by next-generation sequencing. Best overall response was determined using Response Evaluation Criteria in Solid Tumors 1.1.

RESULTS

We identified 3 groups of patients: ERBB2-mutant/EGFR-wildtype mNSCLC (n = 33), ERBB2-amplified/EGFR-wildtype mNSCLC without concurrent ERBB2 mutations (n = 6), and ERBB2-altered/EGFR-mutant mNSCLC (n = 8). Observed mutations included A775_G776insYVMA (n = 23), Gly778_Pro780dup (n = 4), Ser310Phe (n = 3), and others (n = 5). Among the 33 with ERBB2-mutant/EGFR-wildtype mNSCLC, those with and without A775_G776insYVMA had significantly different median overall survival (OS) of 17.7 and 52.9 months, respectively (Cox regression multivariable HR: 5.03, 95% CI: 1.37-18.51, P = .02). In those with mNSCLC with A775_G776insYVMA, trastuzumab-based therapies were associated with greater OS (20.3 vs. 9.8 months; multivariable HR: 0.19, 95% CI: 0.04-0.87, P = .032). Objective response and disease control rates (median tumor size change) in the 33 patients with ERBB2-mutant/EGFR-wildtype mNSCLC were 40.0% and 80.0% (-35.8%), respectively, for patients treated with trastuzumab deruxtecan; 0% and 30.0% (-5.2%) for trastuzumab emtansine; and 7.1% and 50.0% (-13.0%) for trastuzumab/chemotherapy combinations.

CONCLUSION

In ERBB2-mutant/EGFR-wildtype mNSCLC, while most trastuzumab-based regimens had modest activity in this real-world analysis, trastuzumab deruxtecan had highest response rates and best tumor size reduction. Receipt of any trastuzumab-based regimen was associated with greater OS with A775_G776insYVMA. There remains an unmet need for approved targeted therapies for ERBB2-mutant/EGFR-wildtype NSCLC.