FDA Grants Orphan Drug Designation to NK Cell Engager DF1001 for Esophageal

DF1001 is currently being studied as both a monotherapy and a combination in a phase 1/2 study that is now recruiting across the United States.

DF1001, a HER2-targeted natural killer (NK) cell engager, has been granted an orphan drug designation by the FDA for the treatment of esophageal cancer, according to a press release issued by Dragonfly Therapeutics.1

DF1001 may promote anti-tumor immunity in patients who are not eligible for or not responding to current therapies and may be effective across a broad range of diseases. It was developed using the TriNKET platform, which is designed to harness NK cells.

The agent is currently being evaluated in the non-randomized, open-label, sequential assignment phase 1/2 study (NCT04143711). The study has an estimated enrollment of 220 participants with an estimated study completion date of December 2023. The primary end points of the study are the number of dose-limiting toxicities and the overall response rate. Secondary end points include serum concentration of DF1001, immunogenicity, best overall response, duration of response, progression-free survival, overall survival, and adverse events.2

After a dose-expansion phase, DF1001 will be tested as both a monotherapy and in combination with other agents across a variety of solid tumors. Monotherapy arms include dose expansions in urothelial bladder cancer, metastatic breast cancer, and in HER2-high expressing cells. In addition to a monotherapy, the agent will be tested in combination with nivolumab (Opdivo) and nab paclitaxel.

In order to participate in the study, patients must be 18 years of age or older, have a confirmed solid tumor, and ECOG performance status of 0 or 1 and a life expectancy of at least 3 months, and adequate hematological, hepatic, and renal function. Patients with rapidly progressing disease, an active history of central nervous system metastases, an organ transplant, an acute or chronic infection, a preexisting autoimmune disease, serious cardiac illness, or poorly controlled hypertension are not eligible to participate.

Currently, the study is recruiting in California, Kansas, Maryland, Michigan, New York, Ohio, Pennsylvania, Rhode Island, Tennessee, and Texas.

1. Dragonfly Therapeutics announces DF1001 granted orphan drug designation in the US for esophageal cancer. News release. Dragonfly Therapeutics. November 9, 2021. Accessed November 9, 2021. https://prn.to/3obSZ0j
2. Study of DF1001 in patients with advanced solid tumors. ClinicalTrials.gov Accessed November 9, 2021. https://bit.ly/3qkWyDX