Immutep Ltd (formerly Prima Biomed) is a biotechnology company working primarily in the field of cancer immunotherapy using the LAG3 immune control mechanism.

Prima currently has three main products in its pipeline, all acquired with Immutep: Eftilagimod alpha, (lab name: IMP321) which is recombinant soluble LAG-3, used as an activator of antigen presenting cells.

This product has completed a Phase IIa clinical study, where it doubled the expected response rate in HER2-negative metastatic breast cancer.

These projects were packaged together and taken public in July 2001 on the ASX in a reverse takeover of a defunct mineral explorer called Prima Resources.

[2] In September 2013 Prima reported top-line interim data from this trial which showed no observed difference between treatment and control group in terms of Progression-free survival (PFS),[3] however in May 2014, when Prima reported final data from CAN-003, it was able to show median PFS for CVac patients in second remission of 12.91 months versus 4.94 months for the control group.

[9] Eftilagimod alpha (lab names: IMP321 or LAG-3Ig) is a soluble dimeric recombinant form of LAG-3, being a fusion protein with immunoglobulin, designed to activate antigen presenting cells.

[13] As of February 2016[update] Prima has registered a Phase I study in conjunction with an existing approved checkpoint inhibitor pembrolizumab in late stage melanoma.

[15] Prima announced a 'single digit' million dollar milestone related to GSK2831781's commencement of a Phase I study in psoriasis in January 2015.

[16] There is evidence, in the tuberculin-induced DTH model in primates, that a single injection of a depleting LAG-3 monoclonal antibody can prevent Th1-driven skin inflammation.

[19] On 19 and 20 May 2015, just after Prima announced final Overall Survival data for its CAN-003 study of CVac, the company's ADRs experienced a significant two-day increase on Nasdaq.

The Prima board is chaired by Australian-born scientist Russell Howard who took on the role in November 2017 following the resignation of Australian businesswoman Lucy Turnbull after seven years as chairperson.