“Creativity is intelligence having fun”

– Albert Einstein

Our novel technology and unique culture pave the way to game changing therapeutics

Amunix aims to mitigate the toxicity of T cell engagers (TCEs) and cytokines by creating drugs that are preferentially activated in the tumor microenvironment, thus driving tumor cell killing while minimizing on-target, off-tumor toxicity that can damage healthy tissues and/or cause CRS. 

T Cell Engagers

TCEs Directly Activate T Cell Killing and Initiate a Cytokine Amplification Cascade that Enhances Anti-Tumor Activity and Can Promote Long-Term Immunity
Immunotherapy illustration


Our Pro-XTEN technology exploits the intrinsically high protease activity of tumors to preferentially unmask and activate our drugs in the tumor microenvironment. The two proprietary components of this technology are as follows:

  1. XTEN® Mask. Our XTEN mask is a polypeptide that serves a dual purpose of acting as a universal mask and providing half-life extension. In contrast to first-generation masks, our novel XTEN masks do not require customized and specific binding to the functional region of the drug, instead acting as a spatial shield that occupies space around the functional region. This mechanism of spatial shielding allows XTEN masks to be universally applicable regardless of the sequence or characteristics of the protein being masked.
  2. Protease-Cleavable Linker. Our protease-cleavable linker enables preferential unmasking and drug activation in the tumor microenvironment. We designed it to be universally cleaved across tumor types to drive efficacy, yet remain largely intact in systemic circulation and in healthy tissues to enable safety.

Pro-XTEN Technology: Our Solution to Mitigate the Toxicity of TCEs and Cytokines
Amunix Pro_XTEN illustration

XPAT® Structure: Three Modular Components

Tandem scFvs 

  • Bind CD3 and tumor target
  • Active drug has short half-life for rapid clearance
  • Validated TCE format (Amgen’s Blincyto)

Universal XTEN Masks

  • Universal masking of proteins via spatial shielding
  • Half-life extension before cleavage
  • Validated in partners’ clinical studies to have low risk of immunogenicity 

Protease-Cleavable Linkers

  • Preferential unmasking and activation in tumor microenvironment
  • Universal linker designed to be cleaved by 8 proteases for cleavage across breadth of tumors 


Our Solution to TCE Toxicity: XPATs, XTENylated Protease-Activated T Cell Engagers
Amunix XPAT illustration

XPATs are designed to be inactive in healthy tissues and preferentially activated in the tumor microenvironment. This unique design expands their therapeutic index through three mechanisms:

  • Masking of both TAA and CD3 targeting domains. As compared to unmasked or singly masked TCEs, masking of both domains improves tolerability and provides a wider safety margin
  • Preferential unmasking and activation in the tumor microenvironment. Our proprietary protease-cleavable linker has been preclinically validated to be cleaved in tumor tissues yet remain largely intact in circulation and healthy tissues
  • Rapid elimination of the unmasked, activated TCE. Our XPATs have long half-lives in circulation due to the half-life extension properties of XTEN, but the active forms lacking XTEN masks are rapidly cleared, thus minimizing potential toxicity arising from any low rate of unmasking in systemic circulation or healthy tissue

Partnering with Amunix

Amunix has forged technology licensing agreements with multiple biopharmaceutical companies, including Roche and 9 Meters Biopharma, to leverage XTEN and Pro-XTEN.

Our licensing partners continue to advance candidates through preclinical and clinical development. The most advanced program, Sanofi’s Factor VIII (efanesoctocog alfa), which is based on our Pro-XTEN platform, is now in a Phase 3 clinical study. In addition, 9 Meters XTENylated GLP-1 and XTENylated GLP-2 are currently in Phase 2 and preclinical studies, respectively.

As we work to advance our own proprietary oncology pipeline, we will continue to partner with pharmaceutical companies who will incorporate our technologies into novel products across a spectrum of therapeutic areas.


Please contact bd@amunix.com if you’re interested in partnering opportunities.