Phase 3 MAVERICK Trial Backs MRI Surveillance Alone Over PCI in SCLC

Results from the international phase 3 SWOG S1827 MAVERICK trial (NCT04155034) show that brain MRI surveillance alone improved cognitive failure-free survival (CFFS) compared with MRI surveillance plus prophylactic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC).1 The findings, presented at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer (WCLC) in Seoul, South Korea, support MRI surveillance alone as the standard of care for this population. For decades, PCI has followed initial therapy for SCLC based on pre-MRI-era data showing it reduced brain metastases and improved overall survival (OS). MAVERICK was designed to test whether modern MRI surveillance could allow patients to forgo PCI—and its associated cognitive and other toxicities—without compromising survival.

Study Design

The trial enrolled 304 patients with limited-stage or extensive-stage SCLC between January 2020 and December 2025.² All participants had completed initial therapy and had no evidence of brain metastases on MRI at enrollment. Patients were randomly assigned to MRI surveillance alone or MRI surveillance plus PCI (25 Gy in 10 fractions). In both arms, brain MRIs were performed every 3 months during year 1 and every 6 months during year 2, with cognitive testing—including the Hopkins Verbal Learning Test-Revised, Controlled Oral Word Association test, and Trail Making Test—conducted at the same intervals. CFFS was the trial's primary end point.

Efficacy and Safety Findings

At a median follow-up of 22 months among living patients, MRI surveillance alone significantly improved CFFS, reducing the risk of cognitive failure or death by 40% compared with MRI plus PCI (HR, 0.60; 90% CI, 0.46-0.78; P = .001).¹ The benefit was consistent among patients with limited-stage and extensive-stage disease and regardless of immunotherapy use. A preliminary OS analysis, conducted after 128 deaths, showed no apparent difference between strategies (HR, 0.90; 90% CI, 0.67-1.20); the final OS analysis is planned after 190 deaths. Brain metastasis-free survival also did not differ significantly between arms (HR, 1.25; 90% CI, 0.95-1.66). Serious treatment-related adverse events were less frequent with MRI surveillance alone: grade 3 to 5 events occurred in 0.8% of patients in the MRI-alone arm vs 7.9% of those who also received PCI (P = .004). One grade 5 encephalopathy event occurred in the MRI-plus-PCI arm.

Clinical Context and Limitations

PCI became standard of care for SCLC following pre-MRI-era trials, including an Auperin meta-analysis and a 2007 EORTC trial, that showed an OS benefit but were limited by heterogeneous or absent brain staging and surveillance imaging. A 2017 Japanese randomized trial incorporating MRI surveillance found no significant PFS or OS difference with the addition of PCI in extensive-stage disease, raising the question MAVERICK was designed to answer directly. MAVERICK is the first randomized phase 3 trial to evaluate MRI surveillance with or without PCI across both limited-stage and extensive-stage SCLC using a standardized, prospective cognitive-testing battery. The final OS analysis, along with longer follow-up on brain metastasis outcomes, remains pending.

"MRI surveillance alone was associated with improved cognitive failure-free survival compared to a strategy of MRI surveillance plus PCI. The benefit of MRI surveillance alone also appears to be consistent across patients with both limited-stage and extensive-stage small cell lung cancer," said Chad Rusthoven, MD, of the University of Colorado School of Medicine and the study presenter.¹ "These results support MRI surveillance alone as the standard of care for patients with SCLC."

REFERENCES

1. Phase III MAVERICK trial supports brain MRI surveillance alone as standard of care for small-cell lung cancer. News release. International Association for the Study of Lung Cancer. September 13, 2026. Accessed September 17, 2026. https://tinyurl.com/4hn3bcwe

2. MRI Brain Surveillance Alone Versus MRI Surveillance and Prophylactic Cranial Irradiation (PCI): A Randomized Phase III Trial in Small-Cell Lung Cancer (MAVERICK). ClinicalTrials.gov. Accessed September 17, 2026. https://clinicaltrials.gov/study/NCT04155034