In the United States, Orphan Drug designation is granted by the U.S. Food and Drug Administration (FDA) to drugs or biologics that are being developed for rare conditions. Rare conditions are defined as those affecting 200,000 people or fewer nationwide. This designation also comes with incentives for drug developers—such as fee waivers, tax credits, and 7 years of market exclusivity upon approval—as rare disease drug development has, historically, been prioritized lower than drug development in more common or “profitable” conditions. Cancer Network recently reported that the FDA granted Orphan Drug designation to osemitamab for the treatment of pancreatic cancer (specifically pancreatic adenocarcinoma) that expresses Claudin18.2.
Osemitamab (TST001) is described by Transcenta as a high-affinity humanized monoclonal antibody that:
kills Claudin18.2 expressing tumor cells by mechanisms of antibody-dependent cellular toxicity and complement-dependent cytotoxicity.
It was developed using Transcenta’s proprietary Immune Tolerance Breaking Technology platform. The Orphan Drug designation hinged, in part, on data from a Phase 1/2 study evaluating the drug’s safety, efficacy, and tolerability. In the study, 6mg/kg osemitamab showed efficacy in patients with pancreatic cancer. The therapy also showed promise in people with gastric cancer that expressed CLDN18.2. While safe and relatively well-tolerated, some participants experienced side effects such as anemia (low red blood cell count), abdominal distention, constipation, and nausea and vomiting.
Moving forward, osemitamab will also be evaluated in a Phase 1/2 trial as a monotherapy and in conjunction with Opdivo; researchers aim to determine if either of these options would contribute to better outcomes over chemotherapy.
About Pancreatic Cancer
Pancreatic cancer begins in the pancreas, an organ that produces enzymes for digestion and hormones like insulin. The cancer can form in the pancreatic ducts (exocrine pancreatic cancer) or in the neuroendocrine (hormone-producing) cells (Islet cell tumors). Symptoms may vary based on which part of the pancreas is affected. Risk factors for this cancer include a family history of pancreatic cancer, smoking cigarettes, obesity, older age, diabetes, chronic pancreatitis, and older age.
Pancreatic cancer often doesn’t show symptoms in early stages. As the cancer progresses and advances, symptoms may appear, including:
- Abdominal pain that radiates to the back
- Appetite loss
- Indigestion
- Fever and chills
- Blood clots
- Newly onset or worsening diabetes
- Jaundice (yellowing of the skin and eyes)
- Unintentional weight loss
- Dark urine
- Greasy, foul-smelling, and pale-colored stools
- Pruritus (extreme itchiness)
- Bowel obstruction
The diagnostic process involves a combination of testing and scans. Treatment varies based on the cancer’s stage (I, II, III, or IV), where the cancer manifested, and how much the patient could tolerate. Potential treatment options include chemotherapy, radiation, and surgery.
