SHANGHAI, Jan. 30, 2023 /PRNewswire/ -- Abbisko Therapeutics Co., Ltd. ("Abbisko Therapeutics" hereafter) today announced that its CSF-1R inhibitor Pimicotinib（ABSK021）has been granted the breakthrough therapy designation from FDA for the treatment of tenosynovial giant cell tumor (TGCT) patients that are not amenable to surgery.

This breakthrough therapy designation approval is based on results from the phase Ib clinical trial of TGCT cohort for Pimicotinib.

Pimicotinib is the world's first new-generation CSF-1R drug candidate recognized by the US FDA as a breakthrough therapy. This is another crucial milestone for Abbisko Therapeutics after Pimicotinib was awarded the "Breakthrough Therapy Drug" certification by the Center for Drug Evaluation, NMPA, in July 2022. The dual recognition of breakthrough therapy in China and the United States demonstrates the innovative research and development strength of Abbisko.

"We are very pleased to learn that the FDA has granted Pimicotinib the Breakthrough Therapy Designation." The granting of this designation also marks an essential step in the R&D and innovation of Abbisko Therapeutics in going global." Dr. Xu Yao-Chang, the chairman and CEO of Abbisko Therapeutics, said, "Pimicotinib's US breakthrough therapy designation shows FDA's recognition of Pimicotinib's early data and affirmation of the company's R&D strength. It will make our clinical development process and finished drug progress more efficient, which will help shorten the time to market and benefit patients worldwide as soon as possible."

Breakthrough Therapy designation is a process designed by the US FDA, China CDE, and other regulatory agencies to expedite the development and review of drugs that are intended to treat a serious condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over available therapy on a clinically significant endpoint.

Pimicotinib is a novel, orally available, highly selective, and highly potent small molecule inhibitor of CSF-1R independently discovered and developed by Abbisko Therapeutics. A number of studies have shown that blocking the CSF-1R signaling pathway could effectively modulate and change macrophage functions, and potentially treat many macrophage-dependent human diseases. Pimicotinib is currently being investigated as a treatment for tenosynovial giant cell tumor (TGCT) and cGVHD, and under evaluation as treatment for a number of other indications.

In July 2022, pimicotinib was granted Breakthrough Therapy Designation from the Center for Drug Evaluation, NMPA for the treatment of TGCT that is not amenable to surgery. Subsequently in October 2022, Abbisko Therapeutics obtained CDE approval to conduct a Phase III clinical trial in TGCT for pimicotinib. Prior to these, pimicotinib demonstrated significant antitumor efficacy in a phase Ib trial in patients with TGCT, achieving a preliminary ORR of 68.0% and favorable safety profile.

Abbisko Therapeutics also completed a Phase Ia dose escalation study for ABSK021 in the U.S. and is conducting an ongoing Phase Ib multi-cohort expansion trial in both the U.S. and China. In addition to TGCT and cGVHD, Abbisko Therapeutics is actively exploring the potential of ABSK021 in treating many other types of solid tumors and has collaborated with Sperogenix (Shanghai) MedTech Co., Ltd. in exploring its potential for treating amyotrophic lateral sclerosis (ALS) among other central nervous system disorders. As of current, no highly selective CSF-1R inhibitor has been approved in China.

About TGCT

TGCT, also known as pigmented villonodular synovitis, is a locally aggressive neoplasm which affects synovial joints, mucous sacs, and tendon membranes, resulting in swelling, pain, stiffness, and decreased activity of the affected joints which seriously affect the patient's quality of life. According to the 2013 World Health Organization classification, TGCTs were classified as localized TGCT and diffuse TGCT. Compared with localized TGCT (80%-90%), the incidence rate of diffuse TGCT is lower (10-20%). Overexpression of colony-stimulating factor 1(CSF1) occurs in most TGCTs.

Surgical resection is the standard treatment for TGCT. However, not all patients are suitable for surgical treatment. It is difficult to remove tumors of diffuse patients by surgery, which may possibly lead to severe joint damage, total synovectomy, joint replacement, or even amputation, and the risk of surgical complications can be high. It has been reported that more than 50% of patients with diffuse TGCT will undergo recurrence after surgical resection. For those TGCT patients not amenable to surgery, there is currently no approved drug available in China.

About cGVHD

Chronic graft-versus-host disease (cGVHD) is the clinicopathological syndrome (including classical cGVHD and overlap syndrome) caused by donor lymphocytes attacking the recipient organs during the process of rebuilding recipient immunity after allogeneic hematopoietic stem cell transplantation, which is one of the major complications after transplantation. According to Chinese consensus on the diagnosis and management of cGVHD (2021), the incidence ranges from 30 to 70%.The clinical manifestations of cGVHD are diverse with great individual differences, and the course of cGVHD is long-lasting. Multiple vital organs can become involved, thereby seriously affecting the quality of life and long-term survival of patients. Glucocorticoids are still the standard first-line treatment for cGVHD but more than half of treated patients will develop resistance and require second-line therapy. There are currently no approved therapeutic agents for patients with cGVHD who have failed to respond to glucocorticoid therapy in China.The main pathophysiological process of cGVHD is immune inflammation, and the common characteristic pathological changes are chronic tissue repair and fibrosis. In this process, macrophage activation dependent on colony stimulating factor (CSF-1) promotes inflammatory response and tissue damage, and accelerates abnormal tissue repair and fibrosis, leading to the manifestations of cGVHD.

About Abbisko Therapeutics

Abbisko Therapeutics (StockCode: 02256) is an oncology-focused biopharmaceutical company founded in Shanghai, dedicated to discovering and developing innovative medicines to treat unmet medical needs in China and globally. The Company was established by a group of seasoned drug hunters with rich R&D and managerial expertise from top multinational pharmaceutical companies. Since its founding, Abbisko Therapeutics has built an extensive pipeline of 15 innovative small molecule programs focused on precision oncology and immuno-oncology, and received 16 IND or clinical trial approvals in multiple countries and regions.

Please visit www.abbisko.com for more information.

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