In the phase I dose‐escalation TRAP study17 we showed that ADI‐PEG20 with pemetrexed (Pem) and cisplatin (Cis) chemotherapy (ADIPemCis) was tolerable and produced a 100% disease control rate (DCR) and an objective response rate of 78% in nine patients with ASS1‐deficient thoracic cancers (non‐squamous NSCLC = 4; mesothelioma = 5) (Beddowes et al., 2017). The gene discussed is ASS1; the disease is mesothelioma.