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MAVERICK Phase III data support MRI surveillance alone in SCLC

Edited by Robert McTiernan··2 min read
MAVERICK Phase III data support MRI surveillance alone in SCLC

Brain MRI surveillance without prophylactic cranial irradiation (PCI) improved cognitive failure-free survival and substantially reduced serious treatment-related adverse events in patients with small-cell lung cancer (SCLC), according to Phase III results from the SWOG S1827 MAVERICK trial. The NCI-supported study, sponsored by the SWOG Cancer Research Network, was presented at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer in Seoul. Overall survival remains immature, with the final analysis planned after 190 deaths.

MAVERICK was designed to determine whether modern MRI surveillance could allow patients to avoid PCI and its associated neurotoxicity without compromising survival. At the current analysis, MRI surveillance alone reduced the risk of cognitive failure or death by 40% compared with MRI surveillance plus PCI (HR 0.60; 90% CI 0.46–0.78; p=0.001), while preliminary OS showed no apparent difference between strategies (HR 0.90; 90% CI 0.67–1.20).

The findings strengthen the case for MRI surveillance as an alternative to routine PCI, particularly given the marked reduction in serious treatment-related toxicity, but the final OS analysis will be important in determining whether omission of PCI can be considered definitively non-inferior for survival.

At a median follow-up of 22 months among living patients, MRI surveillance alone reduced the risk of cognitive failure or death by 40% compared with the MRI plus PCI arm (HR 0.60; 90% CI 0.46–0.78; p=0.001). The benefit was consistent across both limited-stage and extensive-stage disease and regardless of whether patients had received immunotherapy. Grade 3–5 adverse events occurred in 0.8% of patients on MRI surveillance alone versus 7.9% in the PCI arm (p=0.004); one grade 5 encephalopathy event occurred in the PCI group.

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A preliminary overall survival analysis after 128 deaths showed no difference between strategies (HR 0.90; 90% CI 0.67–1.20), and brain metastasis-free survival was also not significantly different (HR 1.25; 90% CI 0.95–1.66). The final overall survival analysis is planned after 190 deaths.

The cognitive endpoint was chosen deliberately: PCI's neurological toxicity has been a persistent clinical concern, and earlier randomized data — including a Japanese trial published in 2017 — had already suggested that MRI surveillance could be a viable alternative in extensive-stage disease, at least without compromising survival. MAVERICK extends that evidence to both disease stages and uses a prospective, standardized cognitive battery as the primary measure rather than survival alone, directly quantifying the harm that PCI imposes on brain function.

Chad Rusthoven of the University of Colorado School of Medicine, who presented the data, said the findings "support MRI surveillance alone as the standard of care for patients with SCLC". The magnitude of the cognitive benefit and reduction in serious adverse events strengthens the case for MRI surveillance as an alternative to routine PCI, pending the final overall survival analysis.

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