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NEWS - Detailed

AmMax Bio Provides Update on AMB-05X Program for Tenosynovial Giant Cell Tumor (TGCT)


New Patents Issued and Fast Track Designation Support Development of the Only Locally-Administered Drug Treatment for TGCT 

Positive Proof-of-Concept Results Lead to Extension of Phase 2 Study to Optimize Dosing Regimen for Phase 3 Design

REDWOOD CITY, Calif. Sep. 26, 2022 —AmMax Bio, Inc. (“AmMax”), a private clinical-stage biopharmaceutical company developing innovative therapeutics in oncology, including targeting the colony-stimulating factor 1 receptor (CSF1R), today announced a program update on AMB-05X, the only pharmacological treatment administered locally and directly at the tumor site for tenosynovial giant cell tumor (TGCT).

“In recent months, the AmMax Bio team achieved a number of milestones in advancing our potentially best-in-class therapy, AMB-05X, for the treatment of TGCT,” said Larry Hsu, Ph.D., Chief Executive Officer of AmMax Bio. “We have demonstrated that the local injection of AMB-05X directly to the tumor site yields good clinical efficacy while minimizing the side effects of systemic treatments.  Our primary market research shows that physicians who generally do not prescribe systemic drugs with safety warnings and patient monitoring requirements have a very strong interest in the potential for locally administered AMB-05X to improve the standard of care for TGCT and significantly reducing unacceptable side effects. With the expansion of the AMB-05X program, we have also grown our network of TGCT experts and the feedback we continue to receive, particularly from orthopedic oncologists, reaffirms our confidence that AMB-05X could become an important new treatment for this indication.”

“Now, with Fast Track designation affirming the benefits of AMB-05X and newly issued patents protecting our novel formulation, AmMax is initiating the dose optimization phase of its Phase 2 program with a treatment duration of six months.  Patients experienced positive clinical outcomes and continuous improvement through twelve weeks of dosing and beyond, and we believe that patients will see greater benefit at six months with AMB-05X than any other pharmacological option.”

Significant AMB-05X Program Milestones Over the Last 12 Months

  • Positive clinical efficacy with tumor reduction and meaningful patient-reported functional outcomes observed in all 11 patients over just 12 weeks. ( Identifier: NCT04731675 )

  • PK/PD data presented at ESMO Congress 2022 confirming that AMB-05X sustained high synovial concentrations and pharmacologic activity at the tumor site, with low systemic exposure

  • Issuance of two new patents related to locally administered formulation that extends IP protection through at least 2041

    • US 11,427,641 B2 “Extended Local Release of Anti-CSFR1 Antibodies”​

    • US 11,419,822 B2 “High Concentration Formulations of Anti-CSF1 and Anti-CSF1R Antibodies”

  • FDA granted AMB-05X Fast Track designation for the treatment of TGCT

Significant Milestones and Development Plan to be Achieved Over the Next 12 Months

  • Initiate patient enrollment this quarter for Phase 2b study which will include a six-month initial treatment period with extension up to 2 years.

  • Present final data from the earlier three-month proof-of-concept study at the Connective Tissue Oncology Society (CTOS) meeting in November 2022

  • Read-out initial results from six-month cohorts in the second half of 2023 and use Fast Track designation to increase communication with FDA on final Phase 3 design

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, the primary standard of care for TGCT, carries significant risk to patients, including complications from infections and prolonged postoperative care, and frequent relapse.  A safe and efficacious pharmacological therapy that can be used alongside surgery remains a significant unmet need.  AmMax is uniquely positioned to address this need for patients with TGCT by leveraging the target selectivity and enhanced safety profile of AMB-05X via local intra-articular administration, while creating a sizable commercial opportunity from improved patient care.

About AMB-05X

A potent monoclonal antibody against CSF1R and granted Fast Track designation by the FDA for TGCT, 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 is a private biotechnology company focused on the clinical development of innovative oncology products. Under an exclusive worldwide license from Amgen, Inc., AmMax is leveraging positive proof-of-concept data and an improved safety profile to advance AMB-05X into the next phase of its clinical development program for tenosynovial giant cell tumor (TGCT).  AmMax actively seeks to in-license potentially best-in-class oncology products in areas of significant unmet medical need.

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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