Phase II, open-label, randomized study of first-line zolbetuximab plus gemcitabine and nab-paclitaxel (GN) in Claudin 18.2–positive metastatic pancreatic cancer (mPC).

<jats:p> TPS4667 </jats:p><jats:p> Background: Combinations of folinic acid, fluorouracil (5-FU), irinotecan, and oxaliplatin (FOLFIRINOX) along with GN are standard first-line treatment options for mPC. Despite treatment advances, mPC has a poor prognosis with a 5-year survival rate of < 5%, emphasizing an urgent need for new targeted therapeutics. Claudin 18.2 (CLDN18.2) is a tight junction protein restricted to normal gastric mucosa cells; however, in the context of malignant transformation, CLDN18.2 is frequently expressed in carcinomas derived from organs that do not normally express it, such as pancreatic adenocarcinoma (50-70% express CLDN18.2). Zolbetuximab is a chimeric IgG1 monoclonal antibody that specifically binds to CLDN18.2, designed to mediate cancer cell death through antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Methods: This phase 2 study (NCT03816163) with a safety lead-in phase will assess safety and antitumor activity of zolbetuximab plus GN in patients (pts) with histologically confirmed mPC with high CLDN18.2 expression (≥75% of tumor cells demonstrate moderate-to-strong IHC staining). The safety lead-in will assess safety/tolerability of zolbetuximab (n = 3 at 1,000 mg/m<jats:sup>2</jats:sup> on Cycle 1 Day 1 then 600 mg/m<jats:sup>2</jats:sup> Q2W then expand/de-escalate using a 3+3 design) plus GN and confirm the recommended phase 2 dose (RP2D). Dose-limiting toxicities (DLTs), defined as a specified toxicity that occurs during the DLT assessment period and is related to zolbetuximab, will be assessed after Cycle 1 (28 days). After determining the RP2D, approximately 129 pts will be randomly assigned 2:1 to receive either zolbetuximab RP2D Q2W on Days 1 and 15 plus GN on Days 1, 8, and 15 of each cycle ( Arm 1), or GN alone on Days 1, 8, and 15 of each cycle ( Arm 2). Randomization will be stratified by ECOG performance status (0 or 1) and liver metastasis (yes or no). Imaging (CT/MRI) will be performed at baseline and every 8 weeks until investigator-assessed disease progression (per RECIST v1.1 criteria) or the start of other systemic anticancer treatment, whichever comes earlier. Primary objectives are to confirm RP2D (safety lead-in), to assess antitumor activity measured by overall survival (randomization phase), and to establish the safety/tolerability profile of zolbetuximab plus GN across the study. Key secondary endpoints in the randomization phase are progression-free survival and objective response rate. As of January 2020, this study is recruiting pts at 74 centers. Clinical trial information: NCT03816163 . </jats:p>