PD-L1 expression and tumor infiltrating PD-1+ lymphocytes associated with outcome in HER2+ breast cancer patients.

PURPOSE: Clinical trials showing programmed death (PD)-1-PD-ligand 1 (L1) axis as a promising therapeutic target in melanoma and non-small cell lung cancers have made the pathway a focus of recent attention. However, the data regarding PD-L1/PD-1 in breast cancer are inconsistent. Given the heterogeneity of breast cancers, the clinical relevance of PD-L1 and PD-1 tumor infiltrating lymphocytes (TIL) may vary according to subtypes of breast cancer. We aim to investigate PD-L1 expression in a large cohort of breast cancers and analyze its clinico-pathological as well as outcome relationship according to molecular subtypes. Also, we evaluate the relationship of PD-1 TIL and PD-L1 expression with patients' survival, particularly for breast cancers with high TIL. METHODS AND RESULTS: Immunohistochemical analysis of PD-L1 on tissue arrays for 1091 breast cancer patients and PD-1 TIL on 97 whole sections was performed. Associations of PD-L1 with luminal cancers (p < 0.001) and features associated with that subtype [lower histologic grade, absence of necrosis, ER, PR, and AR expression (p < 0.001)] were observed. However, in HER2+ breast cancers, PD-L1 was an independent poor prognostic indicator (DFS: HR = 1.866, p = 0.001; OS: HR = 1.517, p = 0.036). Interestingly, HER2+ cancers showed a lower PD-1 TIL level compared to the other high TIL cases (p = 0.011). Cases with low PD-TIL but high PD-L1 expression showed the worst survival. This could be indicative of an active immune suppression by PD-L1 expression. CONCLUSIONS: Our data showed the relevance of PD-L1 expression in HER2+ breast cancer. A combined evaluation of PD-L1 and PD-1 TIL in the prognosis of breast cancer might also be of value in treatment prediction.

Comparison of tape stripping with the human skin blanching assay for the bioequivalence assessment of topical clobetasol propionate formulations.

PURPOSE: A draft guidance on tape stripping for assessing the bioavailability/bioequivalence of topical formulations was issued by the United States Food and Drug Administration in 1998 but has since been withdrawn. This was due to problems associated with the method and also inconsistencies and variability in the resulting data. The purpose of this study was to re-visit the tape stripping technique, incorporate refinements to reduce variability and validate the method using bioequivalence data obtained from the assessment of a topical corticosteroid cream containing 0.05% clobetasol propionate using the human skin-blanching assay. METHODS: A pilot tape stripping study was conducted to establish the variability of the formulations.The bioequivalence of two different commercially available clobetasol propionate cream formulations and a clobetasol propionate ointment formulation were subsequently investigated using the tape stripping method. RESULTS: The data from the pilot tape stripping study correlated well with data from the human skin-blanching assay. A subsequent pivotal tape stripping study confirmed bioequivalence between the two cream formulations whereas bio-inequivalence was demonstrated between the cream and ointment formulations. CONCLUSIONS: These studies show that the results from tape stripping concur with data from the human skin blanching assay and demonstrate the potential of a well-controlled tape stripping study as an option for the assessment of bioequivalence of topical corticosteroid formulations.

Bioequivalence assessment of topical clobetasol propionate products using visual and chromametric assessment of skin blanching.

PURPOSE: The assessment of the degree of skin blanching following the application of a formulation containing a topical corticosteroid has been established as a surrogate method for the determination of bioequivalence. In this study, both visual and chromametric assessments have been carried out on two topical creams containing clobetasol propionate (0.05%) and the results from both methods are compared. METHODS: Human subjects (volunteers) were screened using a cream containing 0.05%clobetasol propionate, in order to identify appropriate subjects for inclusion in the study. The study was implemented according to the FDA guidance using both visual and chromameter assessment techniques. Blanching responses were assessed visually by three trained, independent observers and instrumentally using a Chromameter. An ED50 of 36 min was used as the dose duration based upon data previously obtained from a pilot study using the same topical corticosteroid reference product. A visual rating scale of 0-4 and the a-scale readings from the chromameter were used. RESULTS: The visual and chromameter blanching profiles showed similar blanching responses with good correspondence. The 90% confidence intervals for the data from both methods were calculated using Locke's method. When only the data obtained from 23 subjects who were identified as"detectors" (as per FDA guidance) were used, the products fell within the bioequivalence acceptance range of 80-125% using the visual assessment method (99.3-111.6%) whereas the data using a chromameter (86.5-129.3%) were just outside the acceptance limits. However, when all subjects (n=34) were included in the calculations, both the visual (97.9-109.2) and chromameter (90.2-120.7) data fell within the bioequivalence acceptance range. CONCLUSIONS: Whereas visual data indicated bioequivalence using either data from "detectors" or data from all subjects, the chromameter data from "detectors" only indicated bioinequivalence but inclusion of all subject data fell within the acceptance range to be declared bioequivalent.