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NEWS - Detailed

AmMax Bio Announces Positive Phase 2 Results Demonstrating Proof-of-Concept for the Novel Local Delivery of AMB-05X in Patients with Tenosynovial Giant Cell Tumor (TGCT)


Intra-Articular Injection Strategy Shows Efficacy Across Multiple Clinical Endpoints and Favorable Safety Profile After 12 Weeks of Therapy 

Data from the Phase 2 Study Support the Potential of AMB-05X as a Best-in-Class Therapy for Treatment of TGCT

REDWOOD CITY, Calif. March 2, 2022 —AmMax Bio, Inc. (“AmMax”), a private clinical-stage biopharmaceutical company developing innovative therapeutics targeting the colony-stimulating factor 1 receptor (CSF1R), today announced additional positive results from the first-of-its-kind local delivery Phase 2 study of AMB-05X via intra-articular (IA) injection for the treatment of tenosynovial giant cell tumor (TGCT).

“These longer-term, 12-week data from eight patients confirm the earlier positive interim results seen after 6 weeks of treatment with AMB-05X,” said Larry Hsu, Ph.D., Chief Executive Officer of AmMax Bio. “With these Phase 2 data, we have now demonstrated proof-of-concept for the intra-articular delivery of AMB-05X in patients with TGCT.  Using our novel approach, we have the potential to truly transform TCGT therapy to ensure an optimal balance of efficacy and safety. Showing best-in-class potential, we look forward to further advancing this program into registration-enabling clinical studies.”

The Phase 2 trial was 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 tumor. ( Identifier: NCT04731675). Key study outcomes included objective response rate (ORR) via magnetic resonance imaging (MRI), improvements in pain, stiffness, range-of-motion, quality-of-life, pharmacokinetics measures and safety.

12-Week Results

All 8 patients who completed 12 weeks of treatment with AMB-05X showed evidence of clinical benefit, including tumor reduction based on RECIST criteria and improvements across many 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. Consistent with its unique IA route of administration, AMB-05X showed an enhanced safety profile as compared to systemic therapies currently on the market or in development. Importantly, in terms of liver transaminase changes, only minimal-to-mild (Grade 1) elevations were observed. Detailed data from the study will be presented at a future medical conference.

“Localized delivery of AMB-05X to patients with TCGT, a serious but non-metastatic tumor, is a highly innovative and logical approach in addressing the well-known side effects associated with the systemically delivered therapies,” said Thomas Scharschmidt, MD, orthopedic oncologist from the James Cancer Hospital / Wexner Medical Center at The Ohio State University and a Principal Investigator in the AmMax trial.  “Although many of my TGCT patients are eager to try new therapies, very few treatment options are available beyond surgical intervention, which itself introduces both safety and post-recovery health challenges. The overall clinical profile of intra-articular AMB-05X appears to address this significant unmet need by offering an effective treatment with a much more tolerable side effect profile. I look forward to helping advance the program during the next stage.”

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 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 a Phase 2 clinical program for tenosynovial giant cell tumor (TGCT).  Based on robust preclinical proof-of-concept results, AmMax is also planning to initiate a Phase 2 clinical study in 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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