Endocyte uses vitamin receptor to tag lung cancer

In a study sponsored by Endocyte ($ECYT) and published online in the journal Archives of Pathology & Laboratory Medicine, researchers screened preserved samples from 188 adenocarcinomas or squamous cell carcinomas of the lung. They found that more than half of the lung cancer samples tested--72% of adenocarcinomas and 51% of squamous cell carcinomas--overexpressed the folate receptor (FR), suggesting that this could be used as a biomarker for these cancers, as well as to target therapeutics. Other cancers also overexpress the FR.

"Lung cancer remains the number one cause of cancer death in the world; however, only a limited percentage of lung cancers are candidates for targeted therapies based on EGFR mutation and ALK fusion genes, demonstrating the need for new targeted therapeutics," said Philip Low, chief scientific officer of Endocyte. "The high level of FR expression in lung cancer suggests that a large percentage of lung cancer patients might benefit from a FR-targeted therapy."

Endocyte's focus is on developing small molecule drug conjugates and companion imaging diagnostics for personalized therapy in FR-positive cancers and inflammatory diseases. One of its conjugates, vintafolide (EC145), which combines the chemotherapeutic vinblastine with the vitamin folic acid, targets the FR and is in Phase III trials for ovarian cancer and Phase IIb trials for non-small-cell lung cancer. Merck ($MRK) is responsible for further clinical studies in additional indications. In April, Merck picked up the exclusive rights to vintafolide in a $1 billion deal. Endocyte is also developing etarfolatide (99mTc-EC20), an FR-targeted molecular imaging agent that can identify FR-overexpressing tumors and be used as a companion diagnostic. This is not part of the deal with Merck.

EC20 has been used in more than 13 of Endocyte's clinical trials and over 590 patients. Being able to select those patients who are FR-positive, and therefore most likely to respond, will help Endocyte and Merck to expedite clinical trials. It will also allow physicians to tailor treatment more accurately, potentially improving outcomes and cutting costs for healthcare providers.

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