Astellas Announces U.S. FDA Grants Priority Review for Zolbetuximab Biologics License Application

On July 6, 2023 Astellas Pharma Inc. (TSE: 4503, President and CEO: Naoki Okamura, "Astellas") reported that the U.S. Food and Drug Administration (FDA) has accepted and granted Priority Review for the company’s Biologics License Application (BLA) for zolbetuximab, a first-in-class investigational Claudin 18.2 (CLDN18.2)-targeted monoclonal antibody, for first-line treatment of patients with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors are CLDN18.2-positive (Press release, Astellas, JUL 6, 2023, View Source [SID1234633047]). If approved, zolbetuximab would be the first CLDN18.2-targeted therapy available in the U.S. for these patients.

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Under the Prescription Drug User Fee Act (PDUFA), the FDA has set a target action date of January 12, 2024. The FDA reviewed the application under its Real-Time Oncology Review (RTOR) program, which aims to explore a more efficient review process to ensure that safe and effective treatments are available to patients as early as possible.

In the U.S., it is estimated that 26,500 people will be diagnosed with gastric cancer and 11,130 will die from the disease in 2023.1 Early-stage gastric cancer symptoms frequently overlap with more common stomach-related conditions, often resulting in gastric cancer diagnosis in the advanced or metastatic stage, or once it has spread from the tumor’s origin to other body tissues or organs.2 The five-year relative survival rate for patients at the metastatic stage is 6.6%.1

"Astellas is committed to bringing innovative therapies to patients with hard-to-treat cancers, including gastric cancer. While rare in the U.S., gastric cancer can be deadly when diagnosed in the late stages," said Moitreyee Chatterjee-Kishore, PhD, MBA, Senior Vice President and Head of Immuno-Oncology Development, Astellas. "The FDA’s acceptance of the Biologics License Application filing and Priority Review designation for zolbetuximab confirms the urgent therapeutic need and brings us one step closer to delivering on this commitment to patients, families and caregivers."

The BLA is based on results from the Phase 3 SPOTLIGHT and GLOW clinical trials. The SPOTLIGHT study evaluated zolbetuximab plus mFOLFOX6 (a combination regimen that includes oxaliplatin, leucovorin and fluorouracil) compared to placebo plus mFOLFOX6. The GLOW study evaluated zolbetuximab plus CAPOX (a combination chemotherapy regimen that includes capecitabine and oxaliplatin) compared to placebo plus CAPOX.

In both SPOTLIGHT and GLOW, approximately 38% of patients screened for the trials had tumors that were CLDN18.2-positive (≥75% of tumor cells with moderate-to-strong membranous CLDN18 staining intensity), as determined by a validated immunohistochemistry assay.3,4

Astellas has already reflected the impact from this acceptance in its financial forecast of the current fiscal year ending March 31, 2024.

About Locally Advanced Unresectable Metastatic Gastric and Gastroesophageal Junction Cancer
Gastric cancer, also commonly known as stomach cancer, is the fifth most commonly diagnosed cancer worldwide.5 In the U.S., it is estimated that 26,500 people will be diagnosed with gastric cancer and 11,130 will die from the disease in 2023.1 Signs and symptoms can include indigestion or heartburn, pain or discomfort in the abdomen, nausea and vomiting, diarrhea or constipation, bloating of the stomach after meals, loss of appetite, and sensation of food getting stuck in the throat while eating.2 Signs of more advanced gastric cancer can include unexplained weight loss, weakness and fatigue, and vomiting blood or having blood in the stool.6 Risk factors associated with gastric cancer can include older age, male gender, family history, H. pylori infection, smoking and gastroesophageal reflux disease (GERD).2,7 Because early-stage gastric cancer symptoms frequently overlap with more common stomach-related conditions, gastric cancer is often diagnosed in the advanced or metastatic stage, or once it has spread from the tumor’s origin to other body tissues or organs.2 The five-year relative survival rate for patients at the metastatic stage is 6.6%.1 Gastroesophageal junction (GEJ) adenocarcinoma is a cancer that starts at the area where the esophagus joins the stomach.8

About Zolbetuximab
Zolbetuximab is an investigational, first-in-class chimeric IgG1 monoclonal antibody (mAb) that targets and binds to Claudin 18.2 (CLDN18.2), a transmembrane protein. Zolbetuximab acts by binding to CLDN18.2 on the cancer cell surface of gastric epithelial cells. In pre-clinical studies, this binding interaction then induces cancer cell death by activating two distinct immune system pathways — antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC).9 Zolbetuximab has not been approved by any regulatory bodies for the treatment of patients with gastric and GEJ cancers, and there is no guarantee the agent will receive regulatory approval or become commercially available for the uses being investigated.

INVESTIGATIONAL STUDIES

About SPOTLIGHT Phase 3 Clinical Trial
SPOTLIGHT is a Phase 3, global, multi-center, double-blind, randomized study, assessing the efficacy and safety of zolbetuximab (IMAB362) plus mFOLFOX6 (a combination regimen that includes oxaliplatin, leucovorin and fluorouracil) compared to placebo plus mFOLFOX6 as a first-line treatment in patients with locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors were CLDN18.2-positive. The study enrolled 565 patients at 215 study locations in the U.S., Canada, United Kingdom, Australia, Europe, South America and Asia. The primary endpoint is progression-free survival (PFS) in participants treated with the combination of zolbetuximab plus mFOLFOX6 compared to those treated with placebo plus mFOLFOX6. Secondary endpoints include overall survival (OS), objective response rate (ORR), duration of response (DOR), safety and tolerability and quality-of-life parameters.

Data from the SPOTLIGHT clinical trial were presented during the 2023 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Gastrointestinal (GI) Cancers Symposium in an oral presentation on January 19 and were subsequently published in The Lancet on April 14.3

For more information, please visit clinicaltrials.gov under Identifier NCT03504397.

About GLOW Phase 3 Clinical Trial
GLOW is a Phase 3, global, multi-center, double-blind, randomized study, assessing the efficacy and safety of zolbetuximab (IMAB362) plus CAPOX (a combination chemotherapy regimen that includes capecitabine and oxaliplatin) compared to placebo plus CAPOX as a first-line treatment in patients with locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors were CLDN18.2-positive. The study enrolled 507 patients at 166 study locations in the U.S., Canada, United Kingdom, Europe, South America and Asia. The primary endpoint is PFS in participants treated with the combination of zolbetuximab plus CAPOX compared to those treated with placebo plus CAPOX. Secondary endpoints include OS, ORR, DOR, safety and tolerability and quality-of-life parameters.

Data from the GLOW study were initially presented at the March 2023 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Plenary Series with an updated oral presentation at the 2023 ASCO (Free ASCO Whitepaper) Annual Meeting on June 3.4

For more information, please visit clinicaltrials.gov under Identifier NCT03653507.

Investigational Pipeline in CLDN18.2
An expanded Phase 2 trial in metastatic pancreatic adenocarcinoma is in progress. The trial is a randomized, multi-center, open-label study, evaluating the safety and efficacy of investigational zolbetuximab in combination with gemcitabine plus nab-paclitaxel as a first-line treatment in patients with metastatic pancreatic adenocarcinoma with CLDN18.2-positive tumors (defined as ≥75% of tumor cells demonstrating moderate-to-strong membranous CLDN18 staining based on a validated immunohistochemistry assay). For more information, please visit clinicaltrials.gov under Identifier NCT03816163.

In addition to zolbetuximab, ASP2138 is under development in our Primary Focus Immuno-Oncology. ASP2138 is a bispecific monoclonal antibody that binds to CD3 and CLDN18.2, and it is currently in a Phase 1 trial for people with gastric, GEJ or pancreatic adenocarcinoma. The safety and efficacy of the agent under investigation have not been established for the uses being considered. For more information, please visit clinicaltrials.gov under Identifier NCT05365581.

There is no guarantee that the agent will receive regulatory approval and become commercially available for the uses being investigated.