Iadademstat + SBRT With Atezo in ES-SCLC

Iadademstat is administered orally (PO) on an empty stomach (two hours after eating or one hour prior to food ingestion). After drinking the entire solution, the participant will be asked to refill the bottle with water and drink it again. Then they will drink another glass of water to wash their mouth and esophagus. Time of administration of the drug should be the same every day, preferentially in the mornings, and the time should be registered using the Dosing Instructions and Participant Drug Diary. If a dose is missed, the dose should be administered as soon as possible within 24 hours of the missed dose time. If more than 24 hours have passed, or a dose is vomited, the participant should call their medical team for instructions.

Atezolizumab will be administered by IV infusion at a fixed dose of 1680mg on Day 1 (+/-3 days) of each 28-day cycle until unacceptable toxicity or loss of clinical benefit as determined by the treating investigator after an integrated assessment of radiographic and biochemical data, local biopsy results (if available), and clinical status. Administration of atezolizumab will be performed in a monitored setting where there is immediate access to trained personnel and adequate equipment and medicine to manage potentially serious reactions.

The first fraction of SBRT should be delivered after the initiation of iadademstat and atezolizumab, ideally between Cycle 1, Day 8, and Cycle 1, Day 15. Initiation of SBRT may be delayed up to 14 days beyond Cycle 1, Day 15 if iadademstat dose adjustment is required for toxicity