Lantheus Holdings, Inc. announced that it has filed a Drug Master File (DMF) with the U.S. Food and Drug Administration (FDA) for NM-01, a PD-L1 imaging biomarker, and will begin making the biomarker available to academic centers and pharmaceutical companies for use in immuno-oncology (I/O) clinical trials in 2021. NM-01 is a proprietary radiopharmaceutical biomarker using a camelid single-domain antibody and a technetium-99 radioisotope that has demonstrated a high affinity for PD-L1 protein. NM-01 could provide a specific, non-invasive approach to patient assessment, including use in whole-body imaging, or virtual biopsy. NM-01 potentially allows detection of PD-L1 expression in tumors and could be used to evaluate patients before, during, or after treatment with I/O agents, including checkpoint inhibitors, in clinical trials. The company has completed a Phase 1 study using NM-01 in 30 non-small cell lung cancer (NSCLC) patients, and preliminary data of the first 16 patients were published in the February 22, 2019 issue of Journal of Nuclear Medicine (Xing et al.). Separately, an investigator-led clinical trial involving 30 patients with either NSCLC or melanoma is in progress at King’s College London and Guy’s and St Thomas’ NHS Trust (NCT04436406); the study aims to monitor treatment response. A clinical trial authorization (CTA) was also granted by the Medicines Healthcare Products Regulatory Agency (MHRA) in November 2020 for a Phase 2 clinical study on NM-01 in NSCLC patients.