Agilent Technologies Inc. (NYSE: A) today announced its Dako PD-L1 IHC 22C3 pharmDx assay has an expanded label approved by U.S. Food and Drug Administration (FDA), for use as an aid in identifying gastric or GEJ adenocarcinoma patients for treatment with KEYTRUDA® (pembrolizumab), an anti-PD-1 therapy manufactured by Merck & Co., Inc., Kenilworth, N.J., USA (known as MSD outside the United States and Canada).

The FDA also announced on September 22 that KEYTRUDA is now approved for the treatment of patients with recurrent locally advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma. These tumors express PD-L1 [Combined Positive Score (CPS) ≥1] as determined by an FDA-approved test, with disease progression on or after two or more prior lines of therapy, including fluoropyrimidine- and platinum-containing chemotherapy and if appropriate, HER2/neu-targeted therapy.

The expanded approvals for PD-L1 IHC 22C3 pharmDx and KEYTRUDA means that these patients now have the possibility of receiving a targeted anti-PD-1 immunotherapy.

Gastric cancer is the fifth most common malignancy worldwide and the third most common cause of cancer death. The prognosis for patients diagnosed with advanced stage IV gastric cancer is poor, with only a 4% five-year observed survival rate*. Previously, gastric or GEJ adenocarcinoma patients had few therapeutic options, and those available included highly toxic chemotherapy.

First approved by U.S. FDA in October 2015, for determining PD-L1 expression levels in patients with NSCLC, PD-L1 IHC 22C3, pharmDx is the first FDA-approved assay for the identification of PD-L1 expression in patients with gastric or GEJ adenocarcinoma for treatment with the anti-PD-1 therapy KEYTRUDA.

“We are pleased that the U.S. FDA approved the expansion of use for PD-L1 IHC 22C3 pharmDx assay, as it gives patients with gastric or GEJ cancer the possibility of having their tumor sample tested for PD-L1 expression, and determining eligibility for treatment with KEYTRUDA,” said Jacob Thaysen, president of Agilent's Diagnostics and Genomics Group.

PD-L1 IHC 22C3 pharmDx was used to assess PD-L1 expression in patients treated with KEYTRUDA in the KEYNOTE-059 trial. KEYNOTE-059 is a registrational, phase 2, global, multicenter, non-randomized, open-label multicohort trial investigating the use of KEYTRUDA in patients with advanced gastric or GEJ adenocarcinoma.

PD-L1 IHC 22C3 pharmDx was developed in partnership with Merck & Co., Inc., Kenilworth, N.J., USA, manufacturer of the anti-PD-1 therapy KEYTRUDA.

KEYTRUDA is a humanized monoclonal antibody that works by increasing the ability of the body's immune system to help detect and fight tumor cells. KEYTRUDA blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes, which may affect both tumor cells and healthy cells.

Agilent is a worldwide leader in partnering with pharmaceutical companies to develop immunohistochemical-based diagnostics for cancer therapy.