Therapeutic Solutions

Immune Therapy for Microbial Diseases

We are a clinical stage biotechnology company focusing on developing novel, broad-spectrum immune-mediated therapeutics for the prevention, treatment and mitigation of a wide range of bacterial, fungal and parasitic microbial infections. The target of our therapeutics, poly N-acetyl glucosamine or PNAG, is a conserved molecule expressed on the surface of a wide range of non-viral microbes.

Immune therapy for microbial infections, such as vaccines, have been around for over 200 years. Unlike antibiotics, immune therapy works by directing the immune system to target and kill infectious microbes. A critical advantage of immune therapy is that the functional components remain within our body so, unlike antibiotics, resistance does not develop. In addition, because the immune system is not an antibiotic it will target microbes that are sensitive or resistant to antibiotics. As has been learned with Covid, immune therapies are most effective if they are widely utilized.

For bacterial pathogens, surface polysaccharides have been used successfully to vaccinate humans against Streptococcus pneumoniae, Hemophilus influenzae type b, Neisseria meningitidis and Salmonella enterica serovar Typhi. However, efficacy is limited to the specific surface polysaccharide included in vaccines or targeted by monoclonal antibodies. What is needed are broad-spectrum immune therapeutics that target a large number of microbial pathogens such that a single vaccine or antibody therapy can be used to prevent serious infectious diseases.


A Broad-Spectrum Target

Alopexx’s proprietary immune therapeutics target the conserved microbial surface polysaccharide poly N-acetyl glucosamine (PNAG). PNAG is a critical component of the microbe’s surface allowing it to adhere to tissues and to survive in the body. Beyond the critical role PNAG serves in helping microbes survive, it has a remarkably wide distribution. PNAG is found on the majority of fungal and bacterial microbes. With rare exception, virtually every microbe we have examined has PNAG on its surface. To date over 75 separate microbial pathogens have been found to express PNAG. This wide distribution of PNAG makes it an ideal target for immune therapeutics and provides, for the first time, a broad-spectrum solution.

A Broad-Spectrum Solution

Alopexx’s immune therapeutics targeting PNAG are comprised of a chemically synthesized vaccine and a fully human monoclonal antibody. Importantly, PNAG is a surface polysaccharide produced by microbes in a similar manner as targets of successful vaccines to organisms such as Streptococcus pneumoniae, Neisseria meningitidis and Hemophilus influenzae. Unlike the narrow-spectrum of these vaccines, the PNAG-targeting therapeutics have the potential to prevent infections caused by a broad-spectrum of microbial pathogens.

Setting Relevant Areas Indications
Infectious Diseases Prevention in high-risk populations
  • ICU patients
  • Emergency abdominal surgery
  • Neonatal infections
  • Burn patients
  • Trauma patients
  • Immunocompromised patients
Expansion of existing vaccines
  • Pneumococcal disease
  • Meningitis
Antibiotic resistant organisms
  • WHO identified threat organisms
Sexually transmitted diseases
  • Gonorrhea
  • Chlamydia
Chronic and difficult to treat infections
  • Chronic lyme disease
  • Recurrent urinary tract infections
  • Eye infections
  • Prosthetic joint infections
Non-Infectious Diseases PNAG-containing microbial fragments have been identified in several tissues and organs from humans and mice with loss of function due to inflammatory destruction. Pre-clinical data indicate immunization against PNAG can prevent this tissue destruction in a variety of non-infectious disease settings.
  • Alzheimer's disease
  • Diabetes
  • Cancer
  • Traumatic brain injury
  • Graft vs host disease

Our Platform

Natural antibodies to PNAG are common in humans and many animal species but these antibodies do not routinely have robust opsonic killing or immune protection against PNAG-producing microbes. This is due to inadequate engagement of the serum complement co-factor system that is needed for the induction of protective immunity. Thus, broad-based immunity to this antigen rarely develops naturally in human or animal populations.

Alopexx’s major proprietary advance was the recognition that this ineffective natural immunity was due to the high degree of acetylation of the native PNAG molecule. Natural PNAG has many acetyl groups on its surface. Those surface acetyl groups are responsible for inducing an ineffective immune response. The acetyl groups can be removed by chemically altering PNAG. This results in a strong protective immunogen that now targets the backbone of PNAG and avoids participation from the acetyl groups. Targeting the backbone of PNAG leads to the induction of antibody-mediated bacterial killing. Alopexx’s vaccine and antibody target the backbone on native PNAG and provide an effective immune response.

Effective Targeting of PNAG

A diagram showing the impact of de-acetylation and mechanism of action of targeting dPNAG.