Efti – as a soluble LAG-3 protein – is an MHC class II agonist and therefore a dendritic-cell activator, causing increased antigen presentation to cytotoxic (CD8+) T cells.
Frédéric Triebel, who discovered LAG-3 in 1990,[2] worked through the 1990s at his laboratory at the Institut Gustave Roussy, in collaboration with INSERM and Merck Serono, to elucidate LAG-3’s role in the adaptive immune system.
Triebel et al. had successfully produced a soluble LAG-3Ig fusion protein by 1995 and subsequently discovered its anti-cancer properties in vivo in different mouse tumor models in 1990.
[citation needed] The INSIGHT Phase I study is investigating the feasibility and safety of different routes of drug delivery (e.g. intra-tumoral, intra-peritoneal, and subcutaneous).
The TACTI-mel Phase I study investigated the safety and potential synergies of efti in combination with the programmed cell death (PD-1) antibody pembrolizumab in unresectable or metastatic melanoma.
In April 2009, Immutep announced its involvement in a Phase I study in pancreatic cancer conducted at Washington University School of Medicine in St. Louis, Missouri.
This trial arose in part from the findings of a June 2005 online paper in Cancer Letters by two researchers at the Centre René Huguenin in Saint-Cloud near Paris who had collaborated with Frédéric Triebel.
This paper demonstrated that the level of serum soluble LAG-3 correlated with improved survival in breast cancer patients whose tumors were estrogen or progesterone receptor-positive.
Immutep granted the rights to efti in mainland China, Hong Kong, Macao and Taiwan in October 2013 to Eddingpharm, a privately held Chinese pharmaceutical company.
Immutep changed their contracted manufacturer to the Shangai-based WuXi PharmaTech, who began producing efti for all trials starting from 2016 onwards.