CCS1477 is the first p300/CBP inhibitor in phase I/IIa clinical trials in patients with advanced solid tumours, such as MYC over-expressing small cell lung cancer, radiation-induced breast sarcoma and metastatic castrate-resistant prostate cancer (ClinicalTrials.gov Identifier: NCT03568656) 110. The gene discussed is EP300; the disease is prostate carcinoma.