The Orphan Drug Act of 1983 was designed to facilitate the development of orphan drugs, or drugs intended for rare or life-threatening indications. In the United States, rare conditions are considered those which affect fewer than 200,000 people nationwide. Through this Act, the Orphan Drug status (or designation) was born. Therapies granted Orphan status earn incentives and benefits for the drug developer, such as fee waivers and 7 years of market exclusivity upon drug approval. Clinical Trials Arena recently reported that Sumitomo Pharma’s therapy TP-1287 for Ewing sarcoma earned Orphan Drug designation in April 2023. 

The National Cancer Institute describes TP-1287 as: 

an orally bioavailable, highly soluble phosphate prodrug of alvocidib, a potent inhibitor of cyclin-dependent kinase-9 (CDK9), with potential antineoplastic activity. Alvocidib targets and binds to CDK9, thereby reducing the expression of CDK9 target genes…and inducing G1 cell cycle arrest and apoptosis (cell death) in CDK9-overexpressing cancer cells.

CDK9 plays a role in the way the cell cycle is regulated. By inhibiting CDK9, Sumitomo Pharma hopes to not just stop the proliferation of cancerous cells, but cause them to die. 

Sumitomo Pharma is currently evaluating TP-1287 in a Phase 1 study in patients with solid tumors. An estimated 80 participants will enroll. Oncological indications include Ewing sarcoma, synovial sarcoma, and dedifferentiated liposarcoma. 

Outside of Orphan Drug designation, TP-1287 also received Rare Pediatric Disease designation from the FDA.

A Brief Overview of Ewing Sarcoma

Ewing sarcoma, part of the Ewing family of tumors, is a rare cancer that grows in bone or in the soft tissue surrounding bones. This tumor often appears in the legs, ribs, arms, spine, or pelvis—and often affects the long bones. Without treatment, Ewing sarcoma may metastasize (spread) to other areas of the body such as the lungs. Although Ewing sarcoma can occur in adults, it is significantly more common in children; in fact, Ewing sarcoma, despite being rare, is the second most common pediatric bone cancer. 

In many cases, the symptoms of Ewing sarcoma are initially overlooked. Children may have swelling or pain in the affected area, but this can be written off as growth pains, sports injuries, or anything similar. Additional symptoms may include:

• A low-grade fever
• Bone pain that worsens at night or after exercise
• Unexplained fatigue
• Unintentional weight loss
• Changes in mobility (such as limping or difficulty moving) 

There are a multitude of therapeutic options for Ewing sarcoma. Chemotherapy, surgery, and radiation therapy may all be used by doctors as curative methods. Currently, an estimated 61-81% of those affected will be treated successfully. This rate drops if the cancer has spread.