19 research outputs found
Comparing modeling strategies combining changes in multiple serum tumor biomarkers for early prediction of immunotherapy non-response in non-small cell lung cancer
BACKGROUND: Patients treated with immune checkpoint inhibitors (ICI) are at risk of adverse events (AEs) even though not all patients will benefit. Serum tumor markers (STMs) are known to reflect tumor activity and might therefore be useful to predict response, guide treatment decisions and thereby prevent AEs.OBJECTIVE: This study aims to compare a range of prediction methods to predict non-response using multiple sequentially measured STMs.METHODS: Nine prediction models were compared to predict treatment non-response at 6-months (nā=ā412) using bi-weekly CYFRA, CEA, CA-125, NSE, and SCC measurements determined in the first 6-weeks of therapy. All methods were applied to six different biomarker combinations including two to five STMs. Model performance was assessed based on sensitivity, while model training aimed at 95% specificity to ensure a low false-positive rate.RESULTS: In the validation cohort, boosting provided the highest sensitivity at a fixed specificity across most STM combinations (12.9% -59.4%). Boosting applied to CYFRA and CEA achieved the highest sensitivity on the validation data while maintaining a specificity >95%.CONCLUSIONS: Non-response in NSCLC patients treated with ICIs can be predicted with a specificity >95% by combining multiple sequentially measured STMs in a prediction model. Clinical use is subject to further external validation.</p
Solid-state NMR applied to photosynthetic light-harvesting complexes
This short review describes how solid-state NMR has provided a mechanistic and electronic picture of pigmentāprotein and pigmentāpigment interactions in photosynthetic antenna complexes. NMR results on purple bacterial antenna complexes show how the packing of the protein and the pigments inside the light-harvesting oligomers induces mutual conformational stress. The protein scaffold produces deformation and electrostatic polarization of the BChl macrocycles and leads to a partial electronic charge transfer between the BChls and their coordinating histidines, which can tune the light-harvesting function. In chlorosome antennae assemblies, the NMR template structure reveals how the chromophores can direct their self-assembly into higher macrostructures which, in turn, tune the light-harvesting properties of the individual molecules by controlling their disorder, structural deformation, and electronic polarization without the need for a protein scaffold. These results pave the way for addressing the next challenge, which is to resolve the functional conformational dynamics of the lhc antennae of oxygenic species that allows them to switch between light-emitting and light-energy dissipating states
Integrating treatment cost reduction strategies and biomarker research to reduce costs and personalize expensive treatments: an example of a self-funding trial in non-small cell lung cancer
Personalization of treatment offers the opportunity to treat patients more effectively based on their dominant disease-specific features. The increasing number and types of treatment, and the high costs associated with these treatments, however, demand new approaches that improve patient selection while reducing treatment-associated costs to ensure sustainable healthcare. The DEDICATION-1 trial has been designed to investigate the non-inferiority of lower dosing regimens when compared to standard of care dosing regimens as a potential effective treatment cost reduction strategy to reduce costs of treatment with expensive immune checkpoint inhibitors in non-small cell lung cancer. If non-inferiority is confirmed, lower dosing regimens could be implemented for all therapeutic indications of pembrolizumab. The cost savings obtained within the trial are partly reinvested in biomarker research to improve the personalization of pembrolizumab treatment. The implementation of these biomarkers will potentially lead to additional cost savings by preventing ineffective pembrolizumab exposure, thereby further reducing the financial pressure on healthcare systems. The concepts discussed within this perspective can be applied both to other anticancer agents, as well as to treatments prescribed outside the oncology field
Comparison of the direct antiglobulin test and the eluate technique for diagnosing haemolytic disease of the newborn
Objective: The direct antiglobulin test (DAT) is an important tool for identification of haemolytic disease of the newborn (HDN) caused by erythrocyte immunization. Although this test has been used for decades, accurate insights into its diagnostic properties and optimal use in the diagnosis of HDN are limited. We aimed to gain more insight into the diagnostic properties of the DAT for HDN by comparing it with erythrocyte eluate screening. Design and methods: DAT and erythrocyte eluate screening was performed in umbilical cord blood of neonates obtained from 317 consecutive deliveries. Clinical jaundice was scored 4Ć¢6 days after delivery for the determination of HDN. Results: In 21 neonates a positive DAT and in 61 neonates a positive eluate screening was found, while only 4 cases of HDN were observed. For the overall population the positive predictive value (PPV) and specificity of the DAT for HDN were 10% and 93% respectively and in the population of neonates with abnormal post-partum jaundice population the PPV and specificity were both 100%. The DAT missed two cases of HDN. These missed cases were, however, positive in the erythrocyte eluate screening. Conclusion: The detection of clinically irrelevant ABO immunization limits the specificity of the DAT and eluate for HDN in ABO-incompatible pregnancies. For optimal use, the DAT should be requested only in cases of jaundice and be interpreted in the context of ABO-incompatibility. Finally, a negative DAT does not rule out HDN. When clinical suspicion is high, an eluate should be added following a negative DAT. Keywords: DAT, Haemolytic disease of the newborn, Eluate, Test performance, Sensitivity, Specificity, NPV, PP
Comparison of the direct antiglobulin test and the eluate technique for diagnosing haemolytic disease of the newborn
Keywords: DAT Haemolytic disease of the newborn Eluate Test performance Sensitivity Specificity NPV PPV a b s t r a c t Objective: The direct antiglobulin test (DAT) is an important tool for identification of haemolytic disease of the newborn (HDN) caused by erythrocyte immunization. Although this test has been used for decades, accurate insights into its diagnostic properties and optimal use in the diagnosis of HDN are limited. We aimed to gain more insight into the diagnostic properties of the DAT for HDN by comparing it with erythrocyte eluate screening. Design and methods: DAT and erythrocyte eluate screening was performed in umbilical cord blood of neonates obtained from 317 consecutive deliveries. Clinical jaundice was scored 4-6 days after delivery for the determination of HDN. Results: In 21 neonates a positive DAT and in 61 neonates a positive eluate screening was found, while only 4 cases of HDN were observed. For the overall population the positive predictive value (PPV) and specificity of the DAT for HDN were 10% and 93% respectively and in the population of neonates with abnormal post-partum jaundice population the PPV and specificity were both 100%. The DAT missed two cases of HDN. These missed cases were, however, positive in the erythrocyte eluate screening. Conclusion: The detection of clinically irrelevant ABO immunization limits the specificity of the DAT and eluate for HDN in ABO-incompatible pregnancies. For optimal use, the DAT should be requested only in cases of jaundice and be interpreted in the context of ABOincompatibility. Finally, a negative DAT does not rule out HDN. When clinical suspicion is high, an eluate should be added following a negative DAT
Current Routine Testosterone Immunoassays Are Unsuitable for Lowering the General Castration Cutoff Recommendation to <0.7 nmol/l (20 ng/dl)
Testosterone measurements are essential in the management of patients with prostate cancer undergoing castration and androgen deprivation therapy. There has been an ongoing discussion on the testosterone castration cutoff (TCC), with the primary focus on large cohort studies in which the testosterone measurement system was not specified or studies that used individual testosterone measurement systems. Here we present a post hoc analysis of a study comparing testosterone measurement systems in a cohort of 120 castrated patients with prostate cancer. We investigated the suitability of general, measurement systemāindependent, TCC values recommended in all clinical guidelines. We show that the four testosterone immunoassays commonly used are unsuitable to support lowering of TCC to 0.7 nmol/l (20 ng/dl) testosterone, since testosterone levels are falsely quantified as higher than this cutoff in 4.2ā29.2% of the castrated cohort, depending on the testosterone immunoassay used. When using 1.0 nmol/l (30 ng/dl) as the TCC for the Beckman immunoassay, 13.3% of the results were falsely quantified as being higher than this value. The results suggest that the measurement systems used in current practice do not support lowering the TCC to 0.7 nmol/l. Furthermore, a more local, immunoassay-dependent TCC should be considered. Patient summary: Patients with advanced prostate cancer who are treated to reduce their testosterone to a castration level are monitored using testosterone measurements. The testing systems currently used for measurement do not support lowering of the testosterone cutoff value to 0.7 nmol/l. Testosterone cutoff values to define castration status should preferably be based on the measurement system in local use
LC-MS/MS assay for the quantification of testosterone, dihydrotestosterone, androstenedione, cortisol and prednisone in plasma from castrated prostate cancer patients treated with abiraterone acetate or enzalutamide
Prostate cancer is the most common malignancy among men in the Western world. Treatment of this patient population, e.g. by (chemical) castration, is primarily focused on depletion of tumor-stimulating androgens, with testosterone being the major androgenic hormone. After initial therapy, prostate cancer may progress to metastatic castration-resistant prostate cancer. Anti-hormonal drugs abiraterone acetate and enzalutamide are commonly used to treat patients with this disease as both drugs reduce tumor growth and increase time to tumor progression. To evaluate the pharmacodynamic effects of anti-hormonal drugs in this patient population, we developed an LC-MS/MS method for the quantification of testosterone, dihydrotestosterone, androstenedione, cortisol and prednisone in human plasma. The validated assay ranges from 10-10,000āpg/mL for testosterone and androstenedione, 100-10,000āpg/mL for dihydrotestosterone, 50-5000āpg/mL for cortisol and 500-50,000āpg/mL for prednisone. Intra-assay and inter-assay variabilities were within Ā±15% of the nominal concentrations for quality control (QC) samples at low, medium and high concentrations and within Ā±20% at the lower limit of quantification (LLOQ), respectively. The applicability of the method was demonstrated in plasma from patients with metastatic castrated-resistant prostate cancer using either abiraterone acetate or enzalutamide
LC-MS/MS assay for the quantification of testosterone, dihydrotestosterone, androstenedione, cortisol and prednisone in plasma from castrated prostate cancer patients treated with abiraterone acetate or enzalutamide
Prostate cancer is the most common malignancy among men in the Western world. Treatment of this patient population, e.g. by (chemical) castration, is primarily focused on depletion of tumor-stimulating androgens, with testosterone being the major androgenic hormone. After initial therapy, prostate cancer may progress to metastatic castration-resistant prostate cancer. Anti-hormonal drugs abiraterone acetate and enzalutamide are commonly used to treat patients with this disease as both drugs reduce tumor growth and increase time to tumor progression. To evaluate the pharmacodynamic effects of anti-hormonal drugs in this patient population, we developed an LC-MS/MS method for the quantification of testosterone, dihydrotestosterone, androstenedione, cortisol and prednisone in human plasma. The validated assay ranges from 10-10,000āpg/mL for testosterone and androstenedione, 100-10,000āpg/mL for dihydrotestosterone, 50-5000āpg/mL for cortisol and 500-50,000āpg/mL for prednisone. Intra-assay and inter-assay variabilities were within Ā±15% of the nominal concentrations for quality control (QC) samples at low, medium and high concentrations and within Ā±20% at the lower limit of quantification (LLOQ), respectively. The applicability of the method was demonstrated in plasma from patients with metastatic castrated-resistant prostate cancer using either abiraterone acetate or enzalutamide