OTL-38 (OTL-0038, Pafolacianine), a fluorescent-labelled folate receptor-α (FRα) targeted imaging agent that accumulates in vivo in tumor cells expressing FR. In 2014, the OTL-38 molecule was granted orphan drug status which can be given to the maker of a drug that treats rare conditions or diseases and offers protection from competition for a period of time. OTL-38 under the brand name Cytalux was approved by the U.S. Food and Drug Administration (FDA) on 29 November 2021, as an additional approach that can be used to identify malignant lesions and to ensure the total resection of the tumors in ovarian cancer patients. Cytalux is a fluorescent drug that targets folate receptor which may be overexpressed in ovarian cancer. Pafolacianine binds to FR-expressing cancer cells with ~1 nM affinity, internalizes via receptor mediated endocytosis, and concentrates in FR-positive cancer tissues. Pafolacianine absorbs light in the near-infrared region within a range of 760 nm to 785 nm with peak absorption of 776 nm and emits fluorescence within a range of 790 nm to 815 nm with a peak emission of 796 nm.

OTL-38 (OTL-0038, Pafolacianine), a fluorescent-labelled folate receptor-α (FRα) targeted imaging agent that accumulates in vivo in tumor cells expressing FR. In 2014, the OTL-38 molecule was granted orphan drug status which can be given to the maker of a drug that treats rare conditions or diseases and offers protection from competition for a period of time. OTL-38 under the brand name Cytalux was approved by the U.S. Food and Drug Administration (FDA) on 29 November 2021, as an additional approach that can be used to identify malignant lesions and to ensure the total resection of the tumors in ovarian cancer patients. Cytalux is a fluorescent drug that targets folate receptor which may be overexpressed in ovarian cancer. Pafolacianine binds to FR-expressing cancer cells with ~1 nM affinity, internalizes via receptor mediated endocytosis, and concentrates in FR-positive cancer tissues. Pafolacianine absorbs light in the near-infrared region within a range of 760 nm to 785 nm with peak absorption of 776 nm and emits fluorescence within a range of 790 nm to 815 nm with a peak emission of 796 nm.