Development of a PD-L1 Complementary Diagnostic Immunohistochemistry Assay (SP142) for Atezolizumab.

Cancer immunotherapies, such as atezolizumab, are proving to be a valuable therapeutic strategy across indications, including non-small cell lung cancer (NSCLC) and urothelial cancer (UC). Here, we describe a diagnostic assay that measures programmed-death ligand 1 (PD-L1) expression, via immunohistochemistry, to identify patients who will derive the most benefit from treatment with atezolizumab, a humanized monoclonal anti-PD-L1 antibody. We describe the performance of the VENTANA PD-L1 (SP142) Assay in terms of specificity, sensitivity, and the ability to stain both tumor cells (TC) and tumor-infiltrating immune cells (IC), in NSCLC and UC tissues. The reader precision, repeatability and intermediate precision, interlaboratory reproducibility, and the effectiveness of pathologist training on the assessment of PD-L1 staining on both TC and IC were evaluated. We detail the analytical validation of the VENTANA PD-L1 (SP142) Assay for PD-L1 expression in NSCLC and UC tissues and show that the assay reliably evaluated staining on both TC and IC across multiple expression levels/clinical cut-offs. The reader precision showed high overall agreement when compared with consensus scores. In addition, pathologists met the predefined training criteria (≥85.0% overall percent agreement) for the assessment of PD-L1 expression in NSCLC and UC tissues with an average overall percent agreement ≥95.0%. The assay evaluates PD-L1 staining on both cell types and is robust and precise. In addition, it can help to identify those patients who may benefit the most from treatment with atezolizumab, although treatment benefit has been demonstrated in an all-comer NSCLC and UC patient population.

Determining the effect of immunosuppressant adherence on graft failure risk among renal transplant recipients.

The objective was to use the United States Renal Data System (USRDS) to quantify the relationship between immunosuppressant therapy (IST) adherence and risk of graft failure among adult renal transplant recipients (RTRs). A secondary objective was to examine the relationship among select patient characteristics and IST adherence. The study sample included adult RTRs who: received primary transplant between January 1, 1999 and December 31, 2005; experienced graft survival for at least 12 months post-transplant and had at least 12 months of data in the USRDS; utilized Medicare coverage for IST; and were prescribed cyclosporine or tacrolimus. IST adherence was measured by medication possession ratio (MPR). Pearson chi-square tests were used to examine associations between patient characteristics and MPR quartiles. Cox proportional hazards regression was used to assess relationships among time to graft failure, MPR, and patient characteristics. Thirty-one thousand nine hundred and thirteen RTRs met inclusion criteria. Older age, female gender, white race, deceased donors, and tacrolimus were associated with greater adherence (p < 0.001). Cox proportional hazard modeling indicated greater adherence, white race, and having a living donor were significantly associated with longer graft survival (p < 0.05). Future prospective studies should further examine the clinical significance of IST nonadherence as it relates to graft failure.