Abstract P5-12-09: The ≥5% cut-off reveals tumor PD-L1 positivity as potential selection biomarker for patient enrollment into the trials evaluating anti-PD-1 or anti-PD-L1 agents in neoadjuvant treatment of triple negative breast cancer

Background: Durable responses of triple negative breast cancer (TNBC) to pembrolizumab (anti-PD-1) or atezolizumab (anti-PD-L1) have been reported in the metastatic setting. Moreover, it is currently being hypothesized that immune checkpoint inhibitors might be more effective in the neoadjuvant setting, due to better preserved anti-tumor immunity in early TN disease. However, biomarkers predictive of response to anti-PD-1 or anti-PD-L1 agents, as well as biomarker-based strategies for testing those drugs in the neoadjuvant setting are still lacking. We evaluated PD-L1 protein expression and the composition of tumor-infiltrating lymphocytes (TILs) in untreated TNBC, in order to get a better insight into the TNBC sub-population(s) which would be suitable for neoadjuvant anti-PD-1 or anti-PD-L1 therapy evaluation. Methods: TNBC patients consecutively treated at the Jean Perrin Comprehensive Cancer Centre (Clermont-Ferrand, France), from 01/01/2010 to 12/31/2014, were included. FFPE tumor tissues were assessed for PD-L1 expression by immunohistochemical (IHC) laboratory-developed test (clone 28-8, Abcam), in tumor cells (tPD-L1) and in TILs. Positivity cut-offs evaluated were ≥1%, ≥5% and ≥10%. The amount CD8+, CD4+, FoxP3+ or PD-1+ TILs was determined by counting those cells, detected by IHC methods, within 5 consecutive HPFs (x400), from tumor invasive front toward tumor center. Clinical disease stage was determined using the TNM system. Results: One hundred and two TNBCs were assessed. There were 28.4%, 23.5% or 16.7% tPD-L1-positive cases (cs), for cut-offs ≥1%, ≥5% or ≥10%, respectively. Similarly, 32.4%, 15.7% or 5.9% of cs were positive for PD-L1 in TILs, using the same cut-offs. With ≥5% as cut-off, positivity for tPD-L1 significantly correlated with the amount of CD8+ (p=0.023), FoxP3+ (p=0.0036) or PD-1+ TILs (p=0.043). The same cut-off, applied to TILs, revealed significant correlations between PD-L1 positivity and the amount of each CD8+, CD4+ or PD-1+ TILs (p=0.025, 0.039 and 0.0042, respectively). Interestingly, when the ≥5% cut-off was used, tumors of T2 size were most frequently tPD-L1+ (11/41 cs, 26.8%), compared with the T1 (3/35 cs, 8.6%) and T3+T4 (3/18 cases, 16.7%) (p=0.04). With regards to TILs, with the ≥5% cut-off, the PD-L1+ cases belonged exclusively to the T1+T2 group (15/76), whereas the T3+T4 group was PD-L1-negative (0/18 cs). Other two cut-offs revealed only occasional correlations. Conclusion: This single-center, real-world TNBC cohort contained a high number of smaller tumors (T1-T2). The IHC-based PD-L1 assessment, with ≥5% as the positivity cut-off, revealed that approximately 1/4 of TNBC could be candidates for neoadjuvant anti-PD-1/anti-PD-L1 approaches. Combined with the amount of CD8+ and PD-1+ TILs, tumor PD-L1 positivity might make an easy-to-use composite biomarker for the 1st-level patient selection for PD-1 or PD-L1 inhibitors in neoadjuvant TNBC treatment. The 2nd level could exploit, for example, the assessment of mutation burden in tumors with low tPD-L1 or amount of CD8+ or PD-1+ TILs. Such tumors might be more frequent among larger TNBC (T3-T4).

Citation Format: Finck W, Passildas J, Poirier C, Kwiatkowski F, Abrial C, Durando X, Penault-Llorca F, Radosevic-Robin N. The ≥5% cut-off reveals tumor PD-L1 positivity as potential selection biomarker for patient enrollment into the trials evaluating anti-PD-1 or anti-PD-L1 agents in neoadjuvant treatment of triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-09.

Biocompatible magnetic polymer carriers for in vivo radionuclide delivery

The magnetic guidance of antiplastic and antibacterial agents as well as x-ray and MRI contrast substances in vivo by means of magnetic particles has been attempted repeatedly during the last 2 decades with more or less success. When using microparticles, the circulation time in the blood, the biodistribution, and to a greater or lesser extent, the specific targeting are determined by the uniformity of size, chemical composition, surface modification, and the electric surface charge. The electrophoretic mobility is an important parameter for the prediction of the usefulness of the prepared particle, modified by chemical and biological molecules. For its success, radionuclide therapy depends on the critical relationship between the amount of radioactive isotopes in the target tissue and in critical normal tissue. Because the implementation of radioimmunotherapy for the treatment of cancer has proven to be considerably more difficult than initially anticipated, we propose the use of magnetic nanospheres for the well directed delivery of radionuclides to a tumor after the intravenous administration of the biodegradable colloidal suspension.

[Can disabled persons have "full social value"?]

Starting out from some value theory-based considerations, the author subsequently questions the concept of being "fully adequate" ("vollwertig", literally: "full value") in light of the human condition, and in particular in its relation to persons with disabilities. In the context of biotic, human life as a fundamental value, a critical discussion ensues of the position held by P. Singer concerning person status of beings, with the degree of biotic perfection of man the focal point of discussion here. Extensive thought is given to the rank of human achievement within the social value system, and its meaning to persons with disabilities. Achievement is accepted as a value, given full awareness of its relativity. For persons with profound disablement, for very old and frail persons, an entitlement, without any counter consideration required, to recognition and valuation of their existence is posited, which includes the need to create overall conditions enabling humane dying in light of the concrete circumstances.

[The trend distribution quotient, a new tool for evaluating renal perfusion scintigraphy using 99mTc-DTPA following renal transplantation]

We developed a new quantitative concept in dynamic renal transplant imaging, the Trend Distribution Ratio, and tested its diagnostic usefulness in 137 examinations. This ratio is an expression of the distribution of blood flow velocity in different areas of the kidney. With regard to the differential diagnosis between acute tubular necrosis and the various forms of rejection we arrived at a sensitivity of 0.83 and a specificity of 0.54. A differentiation between the various histological types of rejection has not yet been possible.

Der Trendverteilimgsquotient, ein neues Werkzeug zur Auswertung der Nierenperfusionsszintigraphie mit 99mTc-DTPA nach Nierentransplantation

Wir entwickelten ein quantitatives Auswertungsverfahren der Nierenperfusionsszintigraphie, den Trendverteilungsquotienten (TQ), und unterzogen ihn einer klinischen Validisierung an 137 Untersuchungen. Dieser Quotient ist ein Maß für die Verteilung der Bluteinflußgeschwindigkeiten in den verschiedenen Anteilen der Niere. Wir erreichten bezüglich der differentialdiagnostischen Abgrenzung der verschiedenen Formen der Rejektionsnephropathie vom akuten Nierenversagen eine Sensitivität von 0,83 und eine Spezifität von 0,54. Die Trennung eines normal funktionierenden Transplantats von einer Niere mit bestehender Rejektion gelang mit einer Spezifität von 0,88 und einer Sensitivität von 0,83. Eine Trennung der verschiedenen histologischen Typen der Rejektion war nicht möglich.

A hypothalamic channel-system in the inferior lobes of a trigger-fish (Rhinecanthus aculeatus, Balistidae)

In the course of a general investigation of the optic system in some trigger-fishes, a hypothalamic, ventricular channel-system with pores, leading to the outside of the brain, has been discovered in the inferior lobes of Rhinecanthus aculeatus (Balistidae). A description of the morphological relations of the channel-system to the blood-vessel-supply and the cranium suggests that the organ-systems involved form a functional unit. The possibility of a hormone-producing system is discussed in the light of physiological and ecological aspects.

Chemical structure and pharmacokinetics of 99mTc-labelled aminomethane diphosphonic acid derivatives

99mTc-labelled derivatives of aminomethane diphosphonic acid, general formula: R1R2N-CR3 [PO(OH)2]2, as well as hydroxyethane diphosphonic acid and hydroxypropane monophosphonic acid were investigated with regard to their suitability for skeleton scintigraphy. Bone accumulation was related to chemical structure. It was concluded from the experiments that compounds able to form enols are accumulated to a higher degree and that big substituents influence the affinity to bone negatively by steric hindrance.

[Biological modelling of potassium metabolism]

1. General principles of the modelling of compartments were described with the aim to use this methodology for the investigation of the potassium metabolism. 2. For the modelling of the potassium metabolism the necessary processes of investigation and calculations in the analysis of 42-potassium-kinetics were described in detail at an example. 3. By analogy references to the haemodynamics the general significance of the modelling of compartments was explained.

[Methods and quality of information from myocardial scintigrams in the diagnosis of myocardial infarct]

There is an increasing importance of scintigraphy for the assessment of microcirculation in the myocardium. In animal experiments advantages and disadvantages of negative and positive representation of ischemic myocardiac areas were tried, after experimental infarction in particular. The results by computer scintigraphy prove that positive representation reveals an information on site and extent of an infarction.