Arsanis Announces Two Key Publications Supporting Its Lead Program ASN100

Arsanis, Inc., a clinical-stage biotechnology company developing targeted monoclonal antibodies (mAbs) for pre-emptive treatment and therapy of serious infectious diseases, today announced two scientific publications in the journals Antimicrobial Agents and Chemotherapy (AAC) and mAbs. Together, these two publications confirm the activity of ASN-1 and ASN-2, the human monoclonal antibodies that comprise Arsanis’ lead clinical candidate, ASN100, targeted against Staphylococcus aureus pneumonia.

S. aureus is a common organism that can live on the skin or in the nasal passages of humans and is frequently the cause of serious and life threatening infections. S. aureus secretes an arsenal of different toxins that damage epithelial cells and disrupt the human immune response, and in particular destroy human immune cells needed for defense against infections. ASN100 acts by broadly neutralizing six relevant S. aureus cytotoxins implicated in the pathogenesis of serious infections such as pneumonia. Traditional antibiotics do not neutralize these toxins, and this may contribute to the high mortality rates frequently reported in patients with S. aureus pneumonia.

The data published in AAC demonstrate that ASN-1, a unique, broadly cross-reactive human mAb that neutralizes five of six important S. aureus cytotoxins, displays superior protective efficacy against severe S. aureus pneumonia in an established rabbit model when compared with a single-toxin neutralizing mAb targeting only Hla. These data also show that the rabbit pneumonia model is more clinically relevant than traditional murine models as mice are insensitive to the effects of S. aureus leukocidins while rabbits more closely mimic human sensitivity. The second scientific paper published in mAbs describes the challenging but successful path to Arsanis’ discovery of ASN-2, a highly potent human mAb that is uniquely able to inactivate LukGH (including sequence variants). LukGH is the sixth S. aureus cytotoxin implicated in pneumonia pathogenesis.

“We believe that the combined action of ASN-1 and ASN-2 positions ASN100 to effectively address all strains of S. aureus as the only mAb product in development that neutralizes six human cytotoxins that are key to the pathogenesis of serious infections such as pneumonia,” said Eszter Nagy, M.D., Ph.D., cofounder and Chief Scientific Officer, Arsanis. “ASN100 has the potential to offer a novel, precision approach to address serious and life-threatening infections in high-risk patients.” “The addition of non-antibiotic and pre-emptive approaches like ASN100 to the antibacterial armamentarium should be critical in the face of high mortality and increasing antibiotic resistance globally,” said David Mantus, Ph.D., Chief Development officer. “We are looking forward to initiating our Phase 2 study of ASN100 later this year.”

Please refer to AAC’s online publication for more information about the ASN-1 study, and mAbs’ online publication for more information about ASN-2 discovery.

About ASN100
ASN100 is a combination of two fully human monoclonal antibodies that collectively neutralize six important S. aureus cytotoxins associated with pneumonia pathogenesis. ASN-1 neutralizes alphahemolysin (Hla), a key S. aureus toxin responsible for lung epithelial cell damage, in addition to four S. aureus leukocidins responsible for lysis of human phagocytic (immune) cells: the Panton-Valentine leukocidin (PVL), leukocidin ED, and gamma-hemolysins AB and CB. ASN-2 inactivates the remaining S. aureus leukocidin, LukGH, which is a particularly potent human cytotoxin that is also responsible for lysis of human phagocytes. Arsanis has recently completed a Phase 1 clinical study of ASN100, and plans to initiate a Phase 2 study in 2016.

About Arsanis, Inc.
Arsanis is a clinical-stage biotechnology company leading the development of targeted monoclonal antibodies (mAbs) for pre-emptive therapy and treatment of serious infectious diseases. The company’s current programs address pathogenic processes selectively, rather than aiming to broadly eliminate bacteria, potentially allowing Arsanis to address critical infections without contributing to the problem of antibiotic resistance. The company is building a broad product pipeline addressing the most important Gram-positive and Gram-negative bacterial pathogens threatening hospitalized and high-risk patients. Its lead clinical program, ASN100, is aimed at serious Staphylococcus aureus infections. A Phase 1 clinical trial of ASN100 has recently been completed, and Arsanis expects to initiate a Phase 2 study of ASN100 in 2016.

Arsanis is a U.S. company headquartered in Waltham, Massachusetts, with European research and preclinical development operations headquartered in Vienna, Austria (Arsanis Biosciences GmbH). For more information, please visit the Arsanis website at

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