In mid-January 2023, Kristi Rosa of OncLive reported that the European Medicines Agency (EMA) granted Orphan Drug designation to pimicotinib (ABSK021) for inoperable tenosynovial giant cell tumors (TGCT).
Orphan Drug designation is granted to therapies intended to treat, prevent, or diagnose rare conditions affecting no more than five in every 10,000 people within the European Union. Designed to facilitate the development and authorization of drugs for rare conditions, Orphan Drug designation comes alongside benefits such as protocol assistance, reduced fees, and 10 years of market exclusivity if/when the drug is approved.
Pimicotinib: What We Know
TGCT Support, a Patient Worthy partner, explains that:
Abbisko Therapeutics Co., Ltd. is developing pimicotinib to treat TGCT by targeting a protein that drives the growth of the tumor, known as the colony stimulating factor 1 (CSF1). Pimicotinib is an oral (50mg) daily medication that is designed to block CSF1.
So far, pimicotinib has performed positively in the clinical setting. Updated data from a Phase 1b study show that 50mg pimicotinib once daily led to an objective response rate of 87.5%, compared to 66.7% when taking 25mg daily. Objective response rate refers to how many people within a trial had a partial or complete response to treatment. In this case, there were three complete responses in the 50mg group and two in the 25mg group.
Further, 93.8% of people who had a partial response within six months continued to respond after this time period; 80% of those who had achieved disease stability within six months achieved a partial response after this time period.
Investigators also found that the treatment was safe and relatively well-tolerated, though some adverse reactions did occur. These reactions included facial swelling, itchiness, rashes, dyslipidemia (abnormally elevated blood lipids), and increased:
- Creatinine phosphokinase
- Lactate dehydrogenase
- Aspartate aminotransferase
- Amylase
- Alanine aminotransferase
- α-hydroxybutyrate dehydrogenase
Moving forward, the Phase 3 MANEUVER clinical trial will continue evaluating pimicotinib for tenosynovial giant cell tumors.
About Tenosynovial Giant Cell Tumors (TGCT)
Also known as: Pigmented villonodular synovitis (PVNS); Giant cell tumor of the tendon sheath (GCT-TS)
Tenosynovial giant cell tumors are a group of rare, locally aggressive, and usually non-life-threatening tumors affecting the joint, tendon sheath, bursae, and/or synovium (all elements involved with the tendons). While these tumors can be damaging, causing the thickening and overgrowth of the synovium, bursae, or tendon sheaths, TGCT is benign (non-cancerous).
TGCT may occur in people of all ages but may occur more commonly in those between 25-50 years old. These tumors result from a chromosomal translocation which causes CSF1 overproduction. Without treatment, TGCT can cause damage and degeneration. TGCT is treated with surgery and adjunct radiation in many cases. Turalio was also approved to treat inoperable TGCT.
Symptoms of TGCT may vary based on location, but some potential symptoms include a limited range of motion, pain and swelling in the affected area, joint instability, a locking or popping sensation in joints, and stiffness.
