Ventana pd l1 sp263 assay

The two independent primary endpoints were PFS as per RECIST version 1.1 according to blinded independent central review (BICR) and OS in patients with PD-L1-positive tumors (≥1% of immune cells staining positive within the tumor area of the tissue sample). PD-L1 expression was assessed at a central laboratory with the Ventana PD-L1 (SP263) assay (Ventana Medical Systems, Tucson, AZ). Key secondary endpoints were PFS as determined by BICR according to RECIST version 1.1 and OS in patients in the overall population, irrespective of PD-L1 expression. Other secondary endpoints were ORR, best overall response, and adverse events (AEs). Tumors were assessed using computed tomography or magnetic resonance imaging as previously described.¹⁷ (link) AEs were graded according to the National Cancer Institute Common Terminology Criteria for AEs, version 4.03.¹⁷ (link) We conducted subgroup analyses of these endpoints in patients <65, ≥65 to <75, and ≥75 years of age.

Durvalumab 20 mg/kg i.v. or placebo was administered every 4 weeks for a maximum of 12 months or until disease progression or unacceptable toxicity. Assessments of tumor response were performed using chest computed tomography every 12 weeks for the first 24 months after enrollment, every 4 months from 25 to 48 months, every 6 months from 49 to 60 months, and every 12 months thereafter. Positron emission tomography or esophagography was used to confirm the suspected disease.
For PD-L1 assessments, formalin-fixed paraffin-embedded tissue blocks were cut into 4-μm thick sections, stained with a VENTANA PD-L1 (SP263) assay (Ventana Medical Systems, AZ, USA), and observed with the OptiView DAB immunohistochemistry Detection Kit (Roche Diagnostics, Rotkreuz, Switzerland), according to the manufacturer’s instructions. Assessment of PD-L1 expression was conducted based on tumor proportion score, defined as the percentage of viable tumor cells with partial or complete membrane staining in at least 100 viable tumor cells, which is performed independently and prospectively by two pathologists who were blind to any information about patients. Positive PD-L1 expression was defined as ≥1% of the tumor cells presenting with any membrane staining.

The PD-L1 expression in FFPET samples was assessed by immunohistochemistry (IHC) performed using the VENTANA PD-L1 (SP263) Assay (Ventana Medical Systems, Inc., Tucson, AZ, USA) per the manufacturer’s guidelines.25 (link),26 High expression of PD-L1 was defined as ≥25% of the tumor cells with membrane positivity for PD-L1 at any intensity. Low expression of PD-L1 was defined as <25% of the tumor cells with membrane positivity for PD-L1 at any intensity.