Immutep (ASX:IMM) shares have hit their highest level in early trade after the Sydney biotech company’s lead product candidate was green-lit for possible early regulatory approval in the United States.

Immutep’s drug candidate eftilagimod alpha (“efti”) was granted Fast Track designation by the US Food and Drug Administration for the treatment of metastatic head and neck squamous cell carcinoma (HNSCC).

Efti is a soluble protein that aims to turbocharge the body’s immune system against cancer cells. It was given the designation because of promising interim results from a phase 2 trial evaluating efti in conjunction with Merck’s blockbuster immune checkpoint treatment Keytruda.

A new phase 2b trial evaluating the drug combination is “advancing well” and is expected to start in mid-2021, Immutep said.

The Fast Track designation means Immutep will have access to more frequent meetings with the FDA over drug approval and may be eligible for priority review.

At lunchtime, Immutep shares were up 11.4 per cent to 49c, their highest level since a brief spike in early December.