Novel Checkpoint Inhibition Series – Unique Expertise / Development stage: Phase II

We are really excited to have
 a unique, cellular approach
 that potentially can combat some
of the most challenging tumors
 through reactivating the
patients's own immune system

CEO of APEIRON Biologics AG

APN401 is a first-in-class autologous cellular therapy approach to strengthen the immune system via a key intracellular immune checkpoint. APN401 targets the E3 ubiquitin ligase Cbl-b (Casitas B-lineage lymphoma-b). Cbl-b acts as negative gatekeeper of immunity. Cbl-b knock out mice have been shown to reject various tumors efficiently. Cbl-b can be regarded as master checkpoint: As published, targeting Cbl-b in cancer immunotherapy offers the opportunity to simultaneously override numerous checkpoints, including sensitivity to regulatory T cells, suppression by TGF-β, immune regulation by both CTLA-4 and, by the PD-L1/PD-1 pathway.

APN401 is an advanced therapeutic medical poduct (ATMP) consisting of PBMC of individual patients that have been silenced ex-vivo for the cbl-b gene with an appropriate si-RNA and electroporation. All relevant immune cell types for antitumor immunity such as CD4-T, CD8-T, NK, NKT, B, APC are thereby transiently activated (see figure).

APN401 silencing

The manufacturing process of APN401 is shown below. Importantly, the whole process can be done in the hospital within 24 hours (“at the bedside”), no shipment and external manipulation of individual cells is needed:

APN401 process


Project status:

A single dose, dose escalating study in 16 advanced cancer patients with solid tumors (majority pancreatic cancer) with no standard treatment options has been finished (Wake Forest University, NC; PI Pierre Triozzi). Single administration is safe at all three dose levels, only mild side effects were observed (mostly transient chills, fever), with no signs of auto-immune adverse effects. In several patients, activation of PBMC towards several tumor antigens (IFN-g secretion) was seen up to 6 months after single treatment. Stabilization of previously progressive late stage disease was observed in 4/16 patients (up to 1 year). Results are presented at ASCO 2018.

 Poster APN401 ASCO 2018


A multiple dose Phase Ib trial has been approved by the FDA and is ongoing at Wake Forest university. A randomized Phase II study with multiple dosing in pancreatic cancer in a maintenance setting is in advanced planning stage. Manufacture of cbl-b silenced cells in the Phase II study will be performed with an integrated customized device to further facilitate “on the bed side” treatment.


  • World-wide unique adoptive autologous cellular immunotherapy in clinical stage
  • Based on the intracellular master checkpoint protein cbl-b, potentially applicable for immunotherapy of various tumors
  • Ex-vivo siRNA silencing of PBMC using electroporation - thus no targeting problem, no viral vectors, no off-target problems due to silencing
  • Manufacture of APN401 within one day in the hospital, no shipment of cells
  • Broad patent protection in all major countries

Selected literature:

Bachmaier, K. et al. Negative regulation of lymphocyte activation and autoimmunity by the molecular adaptor Cbl-b. Nature 403, 211-216 (2000).

Jeon, M.S. et al. Essential role of the E3 ubiquitin ligase Cbl-b in T cell anergy induction. Immunity 21, 167-177 (2004).

Krawczyk, C.M. et al. Differential control of CD28-regulated in vivo immunity by the E3 ligase Cbl-b. J Immunol 174, 1472-1478 (2005).

Loeser, S et al. The Ubiquitin E3 Ligase Cbl-b in T Cells Tolerance and Tumor Immunity. Cell Cycle, 6(20), 2478–2485 (2007).

Lutz-Nicoladoni C et al. Reinforcement of cancer immunotherapy by adoptive transfer of cblb-deficient CD8+ T cells combined with a DC vaccine. Immunol Cell Biol. 2012 Jan;90(1):130-4.

Fujiwara M et al. Cbl-b Deficiency Mediates Resistance to Programmed Death-Ligand 1/Programmed Death-1 Regulation. Front. Immunol. 8:42 (2017).