Phase I Trial of CArbonic Anhydrase Inhibition in Combination With Radiochemotherapy or Radioimmunotherapy in Small Cell Lung Carcinoma

This Phase 1 trial is testing whether adding acetazolamide (a drug that blocks an enzyme called carbonic anhydrase) to standard radiation and chemotherapy — or to immunotherapy — can make these treatments work better in patients with small cell lung cancer (a fast-growing type of lung cancer). **You may be eligible if...** - You are 18 or older - You have been diagnosed with small cell lung cancer that has not spread to distant organs (localized disease), OR extensive small cell lung cancer that has already received 4 cycles of chemotherapy plus immunotherapy - You are well enough to handle daily activities (performance status 0–2) - You are scheduled to begin radiation therapy combined with chemotherapy (for localized disease) - Women of childbearing age must have a negative pregnancy test and agree to use contraception **You may NOT be eligible if...** - Your cancer has spread to distant organs (metastatic) - You have previously received radiation to the chest area - You have serious heart failure (ejection fraction below 30%) or severe lung disease (oxygen-dependent COPD, severely reduced lung function) - You have a contraindication to carbonic anhydrase inhibitors (such as sulfa drug allergy) - You are affiliated with a health insurance plan that does not cover the study Talk to your doctor to see if this trial is right for you.