Rare diseases are, by their nature, rare—and because of this, it can be difficult to spur drug development. The FDA worked to overcome this through the creation of the Orphan Drug Act and Orphan Drug designation. This designation is granted to drugs or biologics intended to treat, diagnose, or prevent rare diseases or conditions, defined as those affecting fewer than 200,000 Americans. With this condition comes a variety of incentives: fee waivers, tax credits, and seven years of market exclusivity upon drug approval. According to Healio, in mid-November 2022, ZB131, a therapy designed for cholangiocarcinoma, earned Orphan Drug designation.
Currently, there are few therapeutic options for those with cholangiocarcinoma. Given that the prognosis associated with this cancer is often poor, new therapies are urgently needed. Could ZB131 be this option?
Developed by clinical-stage pharmaceutical company ZielBio, ZB131 is a monoclonal antibody (mAb) that targets cancer-specific plectin (CSP). CSP is pro-tumorigenic, which means it acts as a driver for different cancers. It is selectively expressed on the surface of cancer cells. ZB131 binds to CSP and kills it, helping to stop the spread of cancer, according to preclinical data. Currently, ZB131 is being evaluated in a Phase 1/2 study for various solid tumors. Outside of cholangiocarcinoma, ZB131 is being developed for ovarian and pancreatic cancers.
Understanding Cholangiocarcinoma
Also referred to as bile duct cancer, cholangiocarcinoma forms in the bile ducts which connect the liver, gallbladder, and small intestine. It can be intrahepatic (developing in bile ducts within the liver), distal (developing in the ducts close to the small intestine), or hilar (in the ducts right outside of the liver). While this cancer can occur in people of all ages, it is most common in those aged 50 or older. Other risk factors include smoking, chronic liver disease, congenital bile duct issues, liver parasites, primary sclerosing cholangitis, and diabetes. Symptoms can, but do not always, include:
- Jaundice (yellowing of the skin, eyes, and mucous membranes)
- Fatigue
- Abdominal pain
- Itchy skin (pruritus)
- Unintended weight loss
- Fever and night sweats
- Dark urine and pale stool
- Nausea and vomiting
