Immutep's (ASX:IMM) eftilagimod alfa drug candidate, or efti, now has a clearer potential development path after the early termination of the TACTI-004 study, according to a Tuesday note by Jefferies.

Its root cause analysis increasingly supports TACTI-004 as a potentially isolated product-specific structural issue rather than a failure of efti's biology. The identification of subtle N-glycan differences in the efti material used in TACTI-004 is potentially important.

With prior efti data intact, head and neck squamous cell carcinoma prioritization, fast-track status, and planned manufacturing work, the risk and reward look more constructive despite residual execution risk.

The brokerage upgraded its rating on Immutep to buy from hold with the price target rising to AU$0.08 per share from AU$0.04.