ZB131 Receives FDA Orphan Drug Status for Pancreatic Cancer Treatment

The CSP-targeting antibody, ZB131, is being investigated in a phase 1/2 study of patients with pancreatic cancer and other solid tumors.

The FDA has granted orphan drug designation to ZB131 for the treatment of patients with pancreatic cancer.

"More than 62,000 people in the United States are diagnosed with pancreatic cancer each year, and the five-year survival rate is only 11%," said Kimberly Kelly, PhD, founder and president of ZielBio, in a press release. "We appreciate the special status that the FDA has granted ZB131 with this orphan drug designation for pancreatic cancer, which is typically diagnosed at an advanced stage with few effective treatment options."

ZB131 is a cancer-specific plectin (CSP)-targeting functional antibody. The agent demonstrated anti-tumor activity in preclinical mouse models. Specifically, ZB131 monotherapy significantly prevented tumor growth in most subjects and caused complete regression in 17% of the subjects. Another preclinical study showed that ZB131 given in combination with gemcitabine 100 mg/kg, led to 91% of subjects experiencing tumor growth suppression compared with 74% of those who received gemcitabine alone.

Single-agent ZB131 is being investigated phase 1/2 study of patients with solid tumors, including cholangiocarcinoma, pancreatic, and ovarian cancers (NCT05074472). In the open label, multicenter, dose-escalation study, 37 patients with solid tumors will be enrolled to the dose-escalation or dose-expansion stage. The study will investigate the safety, tolerability, preliminary efficacy of ZB13, as well as the recommended phase 2 dose of the drug. ZB13 will be administered intravenously, every week and will continue until disease progression or unacceptable toxicity.

Patients are eligible to enroll if they are 18 years of age or older with a histological or cytologic diagnosis of an advanced solid tumor. In the pancreatic cancer cohort, patients must be ineligible to receive standard of care therapy. All patients are required to have an ECOG performance status of 0–2, measurable disease per RECIST, a life expectancy of 3 months, adequate hematologic, hepatic, and renal function, and adequate coagulation parameters. Female patients must have a negative pregnancy test and use contraception during the study. Male patients must also use contraception during the study.

The study excludes patients who have undergone major surgery within 4 weeks prior to the study, prior radiotherapy within 2 weeks, anti-cancer therapy within five half-lives or four weeks before the first dose of study treatment. Patients with active central nervous system metastases, evidence of metastatic ileus on CT, severe gastrointestinal illnesses, or severe infection like HIV, hepatitis B, and hepatitis C are excluded from the study. Other infections or comorbidities that may interfere with the effectiveness of ZB131 are also grounds for study exclusion.

Patients who meet the inclusion criteria are actively being recruited at study sites in Arizona, Florida, Minnesota, Tennessee, Texas, Virginia.


1. ZielBio receives orphan drug designation for ZB131 for the treatment of pancreatic cancer. News release. December 27, 2022. Accessed December 28, 2022. https://prn.to/3hROAAv

2. ZielBio to present new data demonstrating preclinical efficacy of ZB131 in cholangiocarcinoma at AACR Annual Meeting 2022. News release. April 12, 2022. Accessed December 28, 2022. https://prn.to/3I0mRrX

3. A phase 1/2, first-in-human, open label, dose escalation study of a CSP targeting functional antibody in solid tumors. Clinicaltrials.gov. Updated September 1, 2022. Accessed December 28, 2022. https://clinicaltrials.gov/ct2/show/NCT05074472?term=NCT05074472&draw=2&rank=1