Safety, Pharmacokinetics, Pharmacodynamics, and Preliminary Efficacy Trial of BNT141 in Patients With Unresectable or Metastatic CLDN18.2-positive Gastric, Pancreatic, Ovarian and Biliary Tract Tumors

The study design consisted of three parts: * Part 1A was a dose escalation of BNT141 as monotherapy in patients with advanced unresectable or metastatic CLDN18.2-positive solid tumors for which there was no available standard therapy considered to confer clinical benefit, or the patient was not a candidate for such available therapy. The dose of BNT141 was planned to be escalated until the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) of BNT141 as monotherapy was defined. However, due to the early study termination, the dose of BNT141 was not fully escalated as planned per protocol (i.e., only four doses were tested, i.e., 0.15 mg/kg, 0.30 mg/kg, 0.45 mg/kg, and 0.60 mg/kg). Once the MTD was reached, up to 10 additional patients with CLDN18.2 expressing pancreatic and biliary tract cancers were planned to be enrolled at the MTD level to obtain additional data on safety, PK and pharmacodynamics (PD). Eligible tumor types were gastric cancer, gastroesophageal junction (GEJ) and esophageal adenocarcinoma, pancreatic, biliary tract (cholangiocarcinoma and gallbladder cancer), and mucinous ovarian cancers. Additionally, patients with specific tumors (including colorectal cancer, non-small-cell lung cancer, gastric subtype of endocervical adenocarcinoma) where there is scientific evidence that the CLDN18.2 could be elevated could be tested for CLDN18.2 expression. * Part 1B was planned to be a dose escalation of BNT141 in combination with nab-paclitaxel and gemcitabine in patients with locally advanced unresectable or metastatic CLDN18.2-positive pancreatic adenocarcinoma or cholangiocarcinoma who were eligible for treatment with nab-paclitaxel and gemcitabine. Part 1B intended to define the MTD and/or RP2D of the combination. Once the MTD was reached, up to 10 additional patients with CLDN18.2-expressing pancreatic adenocarcinoma or cholangiocarcinoma were planned to be enrolled at the MTD level to obtain additional data on safety, PK and PD. The MTD of BNT141 in combination with nab-paclitaxel and gemcitabine in Part 1B was planned to not exceed the monotherapy BNT141 MTD determined in Part 1A. * Part 2 (Expansion) was planned to consist of two predefined expansion cohorts in patients with CLDN18.2-positive solid tumors eligible for treatment with nab-paclitaxel and gemcitabine. Part 1B and Part 2 did not proceed and no participant was enrolled in Part 1B and Part 2.