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NEWS - Detailed

AmMax Bio Announces Positive Interim Phase 2 Results of AMB-05X for the Treatment of Tenosynovial Giant Cell Tumor (TGCT)


Intra-articular (IA) Delivery of AMB-05X Demonstrates Proof-of-Concept in TGCT with a Rapid Onset of Tumor Reduction in All Patients Within Six Weeks 

Interim AMB-05X Data Support Potential for Best-in-Class Therapy for Treatment of TGCT

REDWOOD CITY, Calif. October 20, 2021 —AmMax Bio, Inc. (“AmMax”), a private clinical-stage biotech company developing novel treatments with AMB-05X, its proprietary anti-CSF1R monoclonal antibody platform, today announced positive interim data from a Phase 2 study of AMB-05X for the treatment of tenosynovial giant cell tumor (TGCT).

“We are very excited to report these positive interim results of AMB-05X for the treatment of TGCT”, said Larry Hsu, Ph.D., Chief Executive Officer of AmMax Bio. “We have sought to match our highly potent and selective monoclonal antibody with an optimal local delivery route for superior efficacy and safety, that delivers best-in-class clinical benefits for patients suffering from TGCT.  What we have seen so far supports that AMB-05X could dramatically impact the current treatment paradigm, with an unparalleled fast onset of response after only 6 weeks and no significant adverse events.  We are working closely with our investigators in Europe and the U.S. to complete our Phase 2 program and prepare for a pivotal trial.”

The Phase 2 trial is designed as a 12-week adaptive, multi-center, open-label, proof-of-concept study to evaluate the safety, efficacy and pharmacokinetics of intra-articular injections of AMB-05X in patients with TGCT of the knee – the predominant joint affected by this sarcoma. ( Identifier: NCT04731675). Key study outcomes include overall response rate (ORR) via magnetic resonance imaging (MRI), improvements in pain, stiffness, range-of-motion, quality-of-life, pharmacokinetics measures and safety.

Interim (6-Week) Results

At Week 6 (after 3 doses), a preliminary analysis showed that all 5 enrolled patients exhibited early evidence of clinical benefit, including tumor reduction based on RECIST criteria and improvements across clinically meaningful patient-reported functional outcomes including reduction of pain and stiffness, improvements in quality-of-life measures, and increased range-of-motion of the affected joint. Patient tolerability data for AMB-05X was favorable with no serious adverse events (AEs) and few non-serious Grade 1 or 2 AEs.  Detailed data from the study will be presented at a future scientific conference.

“These interim data are very positive and align with the favorable patient responses we’ve observed during study visits,” stated Hans Gelderblom, M.D., Ph.D., Chair of Medical Oncology at the Leiden University Medical Center in the Netherlands and Principal Investigator of the study. “Improvements in both clinical and radiologic outcomes, coupled with reduced systemic safety risks, suggest that AMB-05X could emerge as an important new therapy for this indication.”

“While surgery is the primary option for most patients with TGCT, the challenges associated with tumor recurrence, post-op recovery, and pain management could be better served by adding optimal pharmacologic options to the treatment mix”, said Michiel van de Sande, M.D., Professor of Orthopedic Oncology, at the Leiden University Medical Center in the Netherlands. “As a locally-administered, non-surgical treatment, AMB-05X could offer an optimal balance of safety and efficacy as a meaningful treatment option.”

About TGCT

Tenosynovial Giant Cell Tumor (TGCT), with a worldwide incidence of over 300,000, is a serious and debilitating locally aggressive tumor in which patients can experience severe pain, disability, and diminished quality of life. Surgical resection is the primary standard of care for TGCT, but carries significant risk to patients, including complications, prolonged postoperative care, infections, and frequent relapse.  A safe and efficacious pharmacological therapy remains a significant unmet need.  AmMax is uniquely positioned to address this need in treating TGCT by leveraging the target selectivity of AMB-05X and its enhanced safety profile, while creating a sizable commercial opportunity from improved patient care.

About AMB-05X

A potent monoclonal antibody against CSF1R, AMB-05X represents a therapeutic platform targeting serious macrophage-driven inflammatory, fibrotic and neovascular diseases.  CSF1R, via its binding to two regulatory cytokines, CSF1 and IL-34, is critically involved in the regulation of macrophages and related cells in multiple biological processes across many organ systems, making it an attractive target with broad therapeutic applications.

About AmMax Bio Inc.

AmMax was founded in March 2020 to develop therapies under an exclusive worldwide license from Amgen, Inc. that leverages the diverse and critical roles played by the colony stimulating factor 1 receptor (CSF1R) signaling pathway for macrophage-driven diseases in multiple organ systems. AmMax is enrolling patients in Phase 2 clinical programs for tenosynovial giant cell tumor (TGCT) and has achieved nonclinical proof-of-concept in both neovascular age-related macular degeneration (nAMD) and idiopathic pulmonary fibrosis (IPF).

For more information, please visit the company’s website at


AmMax Bio, Inc.

Andrew Sauter, CFO


Tel: 650-787-3777

To view the original version on Globe Newswire, please visit 

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