Dr Santos Castillero on MAVERICK, B7-H3 ADCs, and the Shifting SCLC Landscape

Can we drop the PCI at this moment? I would say yes, but you need to be vigilant on the MRI. I was very impressed with the results from the MAVERICK study, so I will continue what I was doing: if the patient is asymptomatic with no brain lesions, I will go on MRI surveillance.

Edgardo S. Santos Castillero, MD, FACP, FASCO, medical director, Broward County, Starling Oncology [editor: confirm practice name; formerly The Oncology Institute of Hope and Innovation]; clinical associate professor, Charles E. Schmidt College of Medicine, Florida Atlantic University; vice president, Florida Society of Clinical Oncology (FLASCO); president, FLASCO Foundation, discussed practice-changing data in small cell lung cancer (SCLC) and molecular testing in a value-based oncology practice.

At the IASLC 2026 World Conference on Lung Cancer (WCLC) in Seoul, the first Presidential Symposium included the phase 3 SWOG S1827 MAVERICK trial (NCT04155034), which randomized patients with limited- or extensive-stage SCLC and no brain metastases to MRI surveillance alone or prophylactic cranial irradiation (PCI) plus MRI surveillance. Santos Castillero said the trial met its end points with no difference between arms [editor: verify against presentation — reported results favor MRI alone on cognitive failure-free survival]. The same session featured positive overall survival (OS) results for 2 B7-H3–directed antibody-drug conjugates (ADCs) vs topotecan in relapsed SCLC: TAISHAN-302 (NCT06612151) of tambotatug pelitecan and ARTEMIS-008 (NCT06498479) of risvutatug rezetecan.

Santos Castillero said that although the discussant suggested PCI may remain an option in limited-stage disease, MRI surveillance for asymptomatic patients has been his practice for 2 years, in part because chemoimmunotherapy has improved systemic control.

He called the B7-H3 ADC data a clear change for extensive-stage SCLC, citing meaningful improvements in median OS, PFS, and response rate with what he described as a relatively favorable toxicity profile. With the phase 3 DeLLphi-305 trial (NCT06211036) of tarlatamab (Imdelltra) plus durvalumab (Imfinzi) as first-line maintenance also reporting positive OS, he said the current standard of chemoimmunotherapy followed by immunotherapy maintenance, and immunotherapy plus lurbinectedin (Zepzelca), may be reshaped. Both ADCs were studied in Asia and will require FDA and EMA review, and how to sequence them alongside tarlatamab is a question he does not yet have an answer to.

On testing, Santos Castillero said a value-based practice has no conflict with comprehensive molecular profiling: identifying an EGFR, ROS1, or HER2 driver delivers the best OS and is more cost-effective than defaulting to expensive chemoimmunotherapy. He closed by flagging the rising incidence of lung cancer in never-smokers, particularly women, as an area requiring urgent study.