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NEWS - Detailed

AmMax Bio Announces First Patients Dosed in Phase 2b Study of AMB-05X for the Treatment of Tenosynovial Giant Cell Tumor (TGCT)


Study designed to optimize treatment regimen and evaluate efficacy over six-month dosing period 

Initial results expected in second half of 2023

REDWOOD CITY, Calif. January 30, 2023 —AmMax Bio, Inc. (“AmMax”), a private clinical-stage biopharmaceutical company developing innovative therapeutics in oncology, including a next-generation antibody-drug conjugate (ADC) and a mAb targeting colony-stimulating factor 1 receptor (CSF1R), today announced that the first patients have been dosed in the Company’s Phase 2b study evaluating AMB-05X for the treatment of tenosynovial giant cell tumor (TGCT).

The AmMax phase 2b trial is an open-label, adaptive, dose-ranging study to evaluate the safety, efficacy and pharmacokinetics of intra-articular administration of AMB-05X in patients with TGCT after 24 weeks of treatment and an additional long-term extension period. ( Identifier: NCT05349643)

“The expansion of our TGCT program into this Phase 2b study builds on the strong proof-of-concept safety and efficacy data reported in 2022 which evaluated the treatment of AMB-05X in TGCT patients over a 12-week period,” said Larry Hsu, Ph.D., Chief Executive Officer of AmMax Bio. “Since announcing those results, both FDA Fast Track designation and EMA PRIME designation have been granted to AMB-05X, reflecting its significant potential to address the unmet medical need for this patient population with few treatment options. With six months of treatment, we believe patients will receive greater benefit with AMB-05X than any other pharmacological options, and we plan to use the data from this trial to finalize our Phase 3 study design.”

“Encouraged by the treatment experience with AMB-05X from the earlier POC study, our patients are excited to enroll in this Phase 2b trial,” stated the principal investigators, Hans Gelderblom, M.D., Ph.D., Chair of Medical Oncology, and Michiel van de Sande, M.D., Professor of Orthopedic Oncology at the Leiden University Medical Center in the Netherlands. “With AMB-05X already demonstrating positive safety and efficacy over a 12-week treatment period, this larger Phase 2b study, with a broader enrollment scope, will assess the treatment durability of this novel, locally administered therapy over a 24-week treatment period. If successful, AMB-05X would provide TGCT patients with a much-needed alternative to immediate surgical resection and the associated complications, long recovery times, and high rates of recurrence.”

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 pharmacologic therapy that can be used as an alternative to 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 granted Fast Track designation by the FDA and PRIME designation by EMA 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 leveraging our core expertise in translational science and drug development to build a clinical portfolio of first-in-class and best-in-class oncology products in areas of significant unmet medical need.

The Company’s core portfolio consists of AMB-101, a novel antibody-drug conjugate (ADC) with a proprietary next generation topoisomerase 1 inhibitor-based linker-payload that is expected to enter the clinic in 2023, and AMB-05X from the Company’s CSF1R platform as a potentially best-in-class locally administered treatment for TGCT. AmMax is currently leveraging positive clinical data and an improved safety profile to advance AMB-05X in an actively enrolling Phase 2 study.

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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