Receptor occupancy assays are used to generate pharmacodynamic (PD) biomarker data that quantifies how much of a target receptor is bound by a drug product at a given time. This data is coupled to pharmacokinetic (PK) profiles to model PK/PD relationships. In pre-clinical and early clinical stages,receptor occupancy assays support compound screening,demonstrate target engagement in disease models,and help establish starting doses for clinical trials. In later-stage programs,RO data informs dose selection and administration schedule decisions.
"},{"faq_question":"What methods does CellCarta use for RO assays? ","faq_answer":"CellCarta uses three validated methodological approaches. The first uses competing and non-competing antibodies to calculate the ratio of unoccupied to total receptors in a whole blood sample. The second uses a saturated vs. non-saturated design with direct detection of the drug through secondary antibody staining,which is useful when receptor-specific monoclonal antibodies are unavailable. The third uses the same saturated vs. non-saturated design but with a functional readout, monitoring cytokine production as a correlate of receptor binding. This last approach is well suited for bi-modal antibodies.
\nCellCarta has the capabilities to execute all three approaches,selecting the most appropriate method based on program requirements and available reagents.
"},{"faq_question":"What sample matrices are used for RO assays? ","faq_answer":"We evaluate both whole blood and PBMC matrices when developing receptor occupancy assays. Matrix selection is a key factor in assay performance,and CellCarta scientists assess which option best fits each program's specific requirements. This evaluation is part of a broader fit-for-purpose assay development process that includes reagent specificity screening,quality control,and regulatory alignment. "},{"faq_question":"Are CellCarta's RO assays regulatory-compliant? ","faq_answer":"Yes. CellCarta's receptor occupancy assays are developed and executed with rigorous quality control in accordance with relevant regulatory requirements,including GCLP. All workflows are designed to produce reliable,audit-ready data that supports regulatory submissions across pre-clinical and clinical stages of drug development. CellCarta's laboratory operations also hold GCLP,CLIA,ISO,and CAP accreditations,providing sponsors with a high-confidence compliance framework for their biomarker programs.
"},{"faq_question":"Can you transfer an existing RO assay? ","faq_answer":"Yes. Our scientists can receive and transfer an already-designed RO assay into CellCarta labs,applying the same development rigor,matrix assessment,reagent specificity screening,and quality control standards used in custom assay builds. This provides sponsors with continuity of data quality when transitioning between laboratories or scaling up from early research to GLP-aligned studies. "}]}#-supreme-cellcarta-featured-resources-16-144{cards-data:[{"image_url":"\/wp-content\/uploads\/2026\/05\/webinar.jpg","card_type":"Webinar","date":"Feb 12","reading_time":"Reading Time - 5 minutes","title":"Resources Title Goes Here","description":"Lorem ipsum dolor sit amet,consectetuer adipiscing elit. Aenean commodo ligula eget dolor.","url":"#"},{"image_url":"\/wp-content\/uploads\/2026\/05\/webinar-2.jpg","card_type":"Webinar","date":"Feb 12","reading_time":"Reading Time - 5 minutes","title":"Resources Title Goes Here","description":"Lorem ipsum dolor sit amet,consectetuer adipiscing elit. Aenean commodo ligula eget dolor.","url":"#"},{"image_url":"\/wp-content\/uploads\/2026\/05\/webinar-3.jpg","card_type":"Webinar","date":"Feb 12","reading_time":"Reading Time - 5 minutes","title":"Resources Title Goes Here","description":"Lorem ipsum dolor sit amet,consectetuer adipiscing elit. Aenean commodo ligula eget dolor.","url":"#"}]}#-supreme-cellcarta-infobox-24-176{tabs-data:[{"tab_title":"Custom Development ","content_title":"","content_body":"CellCarta can develop fit-for-purpose RO assays suited to your drug target,reagent availability,and study needs. Our assays are qualified for exploratory and secondary endpoints and have been extensively employed in clinical trials.
\nReagent specificity is determined through extensive screening during assay development to ensure data quality from the start.
\nAll designs are subject to rigorous QC in accordance with the relevant regulation,including GCLP.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-24.jpg","image_alt":""},{"tab_title":"Multiparametric RO ","content_title":"","content_body":"Our flow cytometry platform enables simultaneous detection of RO and additional PD markers within a single multiparametric panel. This capacity reduces sample requirements and provides a richer pharmacodynamic picture within a single assay run.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-70.jpg","image_alt":""},{"tab_title":"Matrix Selection ","content_title":"","content_body":"\nOptimal matrix selection is a key determinant of RO assay performance. Our team evaluates whole blood and PBMC matrices against program-specific requirements to select the most appropriate option for each assay. This ensures our design is optimized to your study’s parameters.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-99.jpg","image_alt":""},{"tab_title":"Assay Transfer","content_title":"","content_body":"When the science requires,we can transfer predesigned assays to our labs for RO testing. We apply the same rigorous QC,matrix assessment,and reagent specificity to these assays as we do with custom developments,ensuring reliable,regulatory-ready data is generated for your study.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-48.jpg","image_alt":""}];oxy-supreme-cellcarta-infobox-tabs-data:[{"tab_title":"Custom Development ","content_title":"","content_body":"CellCarta can develop fit-for-purpose RO assays suited to your drug target,reagent availability,and study needs. Our assays are qualified for exploratory and secondary endpoints and have been extensively employed in clinical trials.
\nReagent specificity is determined through extensive screening during assay development to ensure data quality from the start.
\nAll designs are subject to rigorous QC in accordance with the relevant regulation,including GCLP.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-24.jpg","image_alt":""},{"tab_title":"Multiparametric RO ","content_title":"","content_body":"Our flow cytometry platform enables simultaneous detection of RO and additional PD markers within a single multiparametric panel. This capacity reduces sample requirements and provides a richer pharmacodynamic picture within a single assay run.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-70.jpg","image_alt":""},{"tab_title":"Matrix Selection ","content_title":"","content_body":"\nOptimal matrix selection is a key determinant of RO assay performance. Our team evaluates whole blood and PBMC matrices against program-specific requirements to select the most appropriate option for each assay. This ensures our design is optimized to your study’s parameters.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-99.jpg","image_alt":""},{"tab_title":"Assay Transfer","content_title":"","content_body":"When the science requires,we can transfer predesigned assays to our labs for RO testing. We apply the same rigorous QC,matrix assessment,and reagent specificity to these assays as we do with custom developments,ensuring reliable,regulatory-ready data is generated for your study.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-48.jpg","image_alt":""}]}#-supreme-cellcarta-infobox-27-176{blocks-data:[{"image":"/wp-content/uploads/2026/06/Receptor-Occupancy-service-106.jpg","image_alt":"Cell Proliferation ","title":"Cell Proliferation ","description":"Assess immune cell division and cycling to evaluate treatment response and immune activation. ","button_text":"Discover","button_url":"/capabilities/immune-monitoring/cell-proliferation-assays/","button_target":"_self"},{"image":"/wp-content/uploads/2026/06/9Receptor-Occupancy-service-9.jpg","image_alt":"Immunoassays","title":"Immunoassays ","description":"Validated platforms and specialized immunology expertise for key biological insights. ","button_text":"Discover","button_url":"/capabilities/immunoassay-services/","button_target":"_self"},{"image":"/wp-content/uploads/2026/06/Receptor-Occupancy-service-80.jpg","image_alt":"CellEngine® Software ","title":"CellEngine® Software ","description":"Advanced flow cytometry analysis and data visualization with incredible speed. ","button_text":"Discover","button_url":"/clinical-trial-services/ai-data-analytics/cellengine-cytometry-software/","button_target":"_self"}];oxy-supreme-cellcarta-infobox-blocks-data:[{"image":"/wp-content/uploads/2026/06/Receptor-Occupancy-service-106.jpg","image_alt":"Cell Proliferation ","title":"Cell Proliferation ","description":"Assess immune cell division and cycling to evaluate treatment response and immune activation. ","button_text":"Discover","button_url":"/capabilities/immune-monitoring/cell-proliferation-assays/","button_target":"_self"},{"image":"/wp-content/uploads/2026/06/9Receptor-Occupancy-service-9.jpg","image_alt":"Immunoassays","title":"Immunoassays ","description":"Validated platforms and specialized immunology expertise for key biological insights. ","button_text":"Discover","button_url":"/capabilities/immunoassay-services/","button_target":"_self"},{"image":"/wp-content/uploads/2026/06/Receptor-Occupancy-service-80.jpg","image_alt":"CellEngine® Software ","title":"CellEngine® Software ","description":"Advanced flow cytometry analysis and data visualization with incredible speed. ","button_text":"Discover","button_url":"/clinical-trial-services/ai-data-analytics/cellengine-cytometry-software/","button_target":"_self"}]}#-supreme-cellcarta-service-blocks-45-176{blocks-data:[{"image":"https://cellcarta.com/wp-content/uploads/2026/08/CellCarta_-44-1-scaled.jpg","image_alt":"","title":"Cell Proliferation ","description":"Assess immune cell division and cycling to evaluate treatment response and immune activation. ","button_text":"Discover","button_url":"/capabilities/immune-monitoring/cell-proliferation-assays/","button_target":"_self"},{"image":"/wp-content/uploads/2026/06/9Receptor-Occupancy-service-9.jpg","image_alt":"","title":"Immunoassays ","description":"Validated platforms and specialized immunology expertise for key biological insights. ","button_text":"Discover","button_url":"/capabilities/immunoassay-services/","button_target":"_self"},{"image":"https://cellcarta.com/wp-content/uploads/2026/06/Receptor-Occupancy-service-80.jpg","image_alt":"Scientist reviewing flow cytometry data on a monitor.","title":"CellEngine® Software ","description":"Advanced flow cytometry analysis and data visualization with incredible speed. ","button_text":"Discover","button_url":"/clinical-trial-services/ai-data-analytics/cellengine-cytometry-software/","button_target":"_self"}]}#-supreme-cellcarta-tab-content-11-144{tabs-data:[{"tab_title":"Custom Development ","content_title":"","content_body":"CellCarta can develop fit-for-purpose RO assays suited to your drug target,reagent availability,and study needs. Our assays are qualified for exploratory and secondary endpoints and have been extensively employed in clinical trials.
\nReagent specificity is determined through extensive screening during assay development to ensure data quality from the start.
\nAll designs are subject to rigorous QC in accordance with the relevant regulation,including GCLP.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-24.jpg","image_alt":"Scientist recording results at a laboratory bench."},{"tab_title":"Multiparametric RO ","content_title":"","content_body":"Our flow cytometry platform enables simultaneous detection of RO and additional PD markers within a single multiparametric panel. This capacity reduces sample requirements and provides a richer pharmacodynamic picture within a single assay run.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-70.jpg","image_alt":"Scientist processing flow samples at an open bench."},{"tab_title":"Matrix Selection ","content_title":"","content_body":"\nOptimal matrix selection is a key determinant of RO assay performance. Our team evaluates whole blood and PBMC matrices against program-specific requirements to select the most appropriate option for each assay. This ensures our design is optimized to your study’s parameters.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-99.jpg","image_alt":"Scientist operating a flow cytometry instrument."},{"tab_title":"Assay Transfer","content_title":"","content_body":"When the science requires,we can transfer predesigned assays to our labs for RO testing. We apply the same rigorous QC,matrix assessment,and reagent specificity to these assays as we do with custom developments,ensuring reliable,regulatory-ready data is generated for your study.
","tab_image":"/wp-content/uploads/2026/06/Receptor-Occupancy-tab-48.jpg","image_alt":"Scientist retrieving samples from laboratory storage."}]}