Circulating tumor DNA landscape and prognostic impact of acquired resistance to targeted therapies in cancer patients: a national center for precision medicine (PRISM) study

BACKGROUND

Despite the effectiveness of the various targeted therapies currently approved for solid tumors, acquired resistance remains a persistent problem that limits the ultimate effectiveness of these treatments. Polyclonal resistance to targeted therapy has been described in multiple solid tumors through high-throughput analysis of multiple tumor tissue samples from a single patient. However, biopsies at the time of acquired resistance to targeted agents may not always be feasible and may not capture the genetic heterogeneity that could exist within a patient.

METHODS

We analyzed circulating tumor DNA (ctDNA) with a large next-generation sequencing panel to characterize the landscape of secondary resistance mechanisms in two independent prospective cohorts of patients (STING: n = 626; BIP: n = 437) with solid tumors who were treated with various types of targeted therapies: tyrosine kinase inhibitors, monoclonal antibodies and hormonal therapies.

RESULTS

Emerging alterations involved in secondary resistance were observed in the plasma of up 34% of patients regardless of the type of targeted therapy. Alterations were polyclonal in up to 14% of patients. Emerging ctDNA alterations were associated with significantly shorter overall survival for patients with some tumor types.

CONCLUSION

This comprehensive landscape of genomic aberrations indicates that genetic alterations involved in secondary resistance to targeted therapy occur frequently and suggests that the detection of such alterations before disease progression may guide personalized treatment and improve patient outcome.

Characterization of the novel HLA-C*05:01:58 allele by sequencing-based typing

HLA-C*05:01:58 differs from HLA-C*05:01:01:02 by a single nucleotide change in codon 112 in exon 3.

Characterization of the novel HLA-DPB1*1139:01 allele by sequencing-based typing

HLA-DPB1*1139:01 differs from HLA-DPB1*04:01:01:03 by one nucleotide substitution in codon 15 in exon 2.

Characterization of the novel HLA-A*36:12 allele by sequencing-based typing

HLA-A*36:12 differs from HLA-A*36:01:01:01 by one nucleotide substitution in codon 211 in exon 4.

Characterization of the novel HLA-DRB1*11:282 allele by sequencing-based typing

HLA-DRB1*11:282 differs from HLA-DRB1*11:04:01:01 by one nucleotide substitution in codon 41 in exon 2.

Characterization of the novel HLA-A*01:367 allele by sequencing-based typing

HLA-A*01:367 differs from HLA-A*01:01:01:01 by one nucleotide substitution in codon 271 in exon 4.

Characterization of the novel HLA-DQA1*03:20 allele by sequencing-based typing

HLA-DQA1*03:20 differs from HLA-DQA1*03:03:01:01 by one nucleotide substitution in codon 33 in exon 2.

Characterization of the novel HLA-C*06:314 allele by sequencing-based typing

HLA-C*06:314 differs from HLA-C*06:02:01:01 by one nucleotide substitution in codon 327 in exon 7.

Factors affecting dairy calf price in auction markets in Québec, Canada: 2008-2019

Dairy calves not kept for replacement are sold at young age in Québec auction markets for white and grain-fed veal calf production. The province of Québec produces 80% of the Canadian veal meat, but little information is available on the factors associated with the calves' price per crude weight (Can$/kg; Can$1 = US$0.78 at time of writing). The characteristics of calves sold in Québec auction markets from 12 complete years (2008-2019) were retrospectively studied. The calves' weight, breed and sex, the year and season of sale, the auction site, as well as the estimated distance traveled between the farm of origin and the auction site were analyzed as potential covariates associated with calf price. Two multivariable logistic models associated with low sale value (below the 10th or the 25th percentile of the day price) and 2 models associated with good sale characteristics (above the 50th or the 75th percentile of the day price) were built. The median distance between the farm and the auction site was 52 km (interquartile range: 30-95 km). Only 5% of calves traveled distances greater than 220 km. The weight, breed, sex, and auction sites explained most of the variability in the different models. Distance traveled and multiple interactions were also significantly associated with the outcomes. Calves with body weight from 48 to <56 kg were sold in higher percentiles of the day than lighter or heavier calves. Beef-crossed calves had better sale prices than Holstein, whereas colored dairy calves had lower sale characteristics than both Holstein and beef-crossed calves. The effect of distance traveled was complex, varying depending on the model and interactions, and explained a small portion of the total deviance in every model. Calves traveling from distances ≥110 km had lower sale characteristics in summer and fall in the different studied models. This study gives relevant insights on calves' characteristics associated with good versus low sale prices in Québec auction markets.

Characterization of the novel HLA-DPA1*01:44 allele by sequencing-based typing

HLA-DPA1*01:44 differs from DPA1*01:03:01:04 by one nucleotide substitution in codon 175 in exon 3.

Immunization against αIIb β3 and αv β3 in Glanzmann thrombasthenia patients carrying the French Gypsy mutation

Essentials The c.1544+1G>A mutation was identified in Gypsy Glanzmann thrombasthenia (GT) patients. Gypsy GT patients express normal αv β3 carrying HPA-1b epitopes. To demonstrate HPA-1a alloimmunization by modified antigen capture assays. Gypsy GT patients could develop anti-HPA-1a alloantibodies against β3 and αv β3 . ABSTRACT: Background Glanzmann thrombasthenia (GT) is a rare bleeding disorder caused by the absence or the dysfunction of the platelet αIIb β3 integrin. A founder mutation in the ITGA2B gene was previously identified in French Gypsy patients. Interestingly, this mutation was strongly linked to the human platelet antigen-1b (HPA-1b). The HPA-1bb Gypsy patients are at risk of isoimmunization against αIIb β3 , as this complex is not expressed at their platelet surface. Tentatively, they would, however, not have an increased risk of developing anti-HPA-1a alloantibodies by exposure of αIIb β3 on platelets from random platelet transfusions. However, the β3 chain can also associate with the αv subunit expressed at the platelet surface. Because Gypsy GT patients express normal αv β3 carrying HPA-1b epitopes, these patients might develop anti-HPA-1a alloantibodies reacting with αv β3 and/or β3 . Objectives/Patients/Methods To demonstrate this hypothesis, sera from HPA-1bb (n = 5) and HPA-1ab (n = 1) Gypsy GT patients were investigated by modified antigen capture assay using platelets or stable transfected cells. Furthermore, stable transfected cells expressing either αIIb β3 or αv β3 together with soluble monomeric chimeric β3 (as absorbent) were used to differentiate anti-β3 and anti-αv β3 reactivity. Results Only HPA-1bb patients developed alloantibodies reacting with HPA-1a cells. Further analysis showed that HPA-1bb patients developed anti-HPA-1a alloantibodies reacting with β3 and/or αv β3 . Conclusion In this study, we found that HPA-1bb patients who failed to express αIIb β3 on the platelet surface can develop alloantibodies against HPA-1a reacting with β3 as well as αv β3 . This is of particular importance as anti-HPA-1a alloantibodies might cause fetal neonatal alloimmune thrombocytopenia and/or platelet transfusion refractoriness.

Improvement in HLA-C typing by a new sequence-specific oligonucleotides kit

PCR-sequence-specific oligonucleotide (PCR-SSO) is commonly used for HLA-typing. We recently replaced LabType SSO HD kit for HLA-C typing with the XR kit (OneLambda, Inc.). We used 137 patients' samples representing unique most likely HLA-C allele combinations to compare these kits' performance. The XR kit decreased the number of allele ambiguities with a median of 26.1% (first to third quartiles 20% to 36.2%, range 0% to 96.1%). The XR kit did not resolve all the common, intermediate and well-documented HLA allele ambiguities, which may be important in the clinical setting. The XR kit eliminated 23.6% of null allele ambiguities. In conclusion, the HLA-C XR kit provides a moderate yet valuable improvement of HLA-typing resolution in comparison with the HLA-C HD kit.

[Relevance of antibodies in hematopoietic stem cell transplantation: Antibodies anti-HLA, anti-platelets, anti-granulocytes, anti-erythrocytes and anti-MICA. Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The presence of allo-antibodies in the serum of a recipient awaiting hematopoietic stem cell transplantation (HSCT) may have an impact on transfusion efficiency and/or donor choice, especially in the absence of an identical sibling donor. Prior to transplantation, donor specific anti-HLA (Human Leukocyte Antigen) antibodies (DSA) have a recognized effect on transplant outcome, correlated with the increasing MFI value and with the ability of such antibody to fix the complement fraction. Anti-platelet antibodies (anti-HLA class I and anti-HPA [Human Platelet Antigen]) are better involved in transfusion inefficiency and can be responsible for refractory status. ABO incompatibilities require a specific treatment of the graft in presence of high titer to avoid hemolytic adverse effects. Investigations of these antibodies should be carried out on a regular basis in order to establish appropriate transfusion recommendation, select an alternative donor when possible or adapt the source of cells. After transplantation, in case of delayed recovery or graft rejection, long term aplasia, persistent mixed chimerism or late release, and after elimination of the main clinical causes, a biological assessment targeted on the different type of antibodies will have to be performed in order to orient towards the cause or the appropriate therapy. Further studies should be carried out to determine the impact of anti-MICA antibodies and recipient specific anti-HLA antibodies, on the outcome of the transplantation.

Characterization of the novel HLA-DPA1*01:03:19 allele by sequencing-based typing

HLA-DPA1*01:03:19 differs from DPA1*01:03:01:02 by one nucleotide substitution in codon 190 in exon 4.

Characterization of the novel HLA-DRB3*02:96 allele by sequencing-based typing

HLA-DRB3*02:96 differs from HLA-DRB3*02:02:01:01 by one nucleotide substitution in codon 189 in exon 4.

Health parameters and their association with price in young calves sold at auction for veal operations in Québec, Canada

The veal calf industry in Québec depends on young calves' availability at auction. Most of these calves come from dairy farms. The aim of this cross-sectional study was to determine the effect of clinical anomalies and other calf characteristics on their sale price. A total of 3,820 calves from 5 different auctions were included in this observational study. The calves were examined by a veterinarian on arrival at the auction and screened for umbilical anomalies, the presence of nasal or eye discharge, joint abnormality, diarrhea, appearance of neonatal characteristics (compatible with age less than 1 wk), and general health status mainly based on the presence of depression and dehydration. The final multivariable model included 5 different variables (calf weight, sex, breed, abnormal joints, and general health status) and the interaction between sex and general health status. The presence of abnormal joints and unhealthy characteristics was negatively associated with standardized price. Female calves and mixed breed beef calves were positively associated with standardized price. Finally, the calves' weight was associated with standardized price in a quadratic fashion. Ongoing or previous diarrhea had no effects on standardized price. This study will be helpful for both dairy and veal producers for improving the quality of calves sold to the Québec auction market.

Management of neonatal thrombocytopenia in a context of maternal antiplatelet alloimmunization: Expert opinion of the French-speaking working group

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, seen in 1/800-1000 neonates. FNAIT is the most common cause of early-onset isolated severe neonatal thrombocytopenia in maternity wards. The most feared complication of this disorder is intracranial hemorrhage, leading to death or neurological sequelae. There is no systematic screening of at-risk pregnancies and FNAIT is often discovered when fetal or neonatal bleeding is observed. A working group on fetomaternal platelet alloimmunization was created in 2017, under the auspices on the French Group of Thrombosis and Hemostasis (GFHT). The first objective of this group was to survey clinical practices for treatment of thrombocytopenic neonates in a context of suspected or confirmed FNAIT.

ÉVALUATION DE LA SÉCURITÉ DE L’IMPLANTATION D’UN PROTOCOLE DE PRISE EN CHARGE DE LA FIÈVRE SANS FOYER D’INFECTION BACTÉRIENNE SÉVÈRE CHEZ LES ENFANTS DE 3 À 36 MOIS À L’URGENCE

HISTORIQUE: En pédiatrie, la fièvre est l’une des raisons de consultation les plus fréquemment rencontrée. Au Centre mère-enfant du CHU de Québec, un protocole est en place pour orienter la prise en charge des enfants de 0 à 36 mois avec fièvre sans foyer. Avant février 2012, le proto-cole impliquait d’administrer un antibiotique chez tous les patients avec critères laboratoire d’infection bactérienne. Par contre, l’incidence des bactériémies occultes et des infections bactériennes sévères ayant significa-tivement diminué depuis la vaccination extensive contre le pneumocoque, un nouveau protocole a été mis en place afin de diminuer le traitement antibiotique des patients avec fièvre sans foyer.

OBJECTIFS: Objectif principal : Parmi les enfants ayant des critères d’antibiothérapie empirique selon l’ancien protocole, comparer le nom-bre de patients ayant eu une modification de traitement (début ou modification d’une antibiothérapie intraveineuse) avant et après l’implantation du nouveau protocole.Objectif secondaire : Chez les enfants ayant une infection bactérienne sévère diagnostiquée lors du suivi, déterminer si l’évolution est similaire chez ceux ayant reçu ou non une antibiothérapie empirique.

MATÉRIELS ET MÉTHODE: Il s’agit d’une étude rétrospective de non-infériorité. Tous les enfants de 3 à 36 mois qui se sont présentés à l’urgence et qui ont été référés en médecine de jour avec un diagnostic de fièvre sans foyer ont été recrutés. Les résultats de l’investigation initiale, le diagnostic final, le nombre de visites en médecine de jour, la durée d’hospitalisation, l’initiation d’une antibiothérapie et la présence de complications graves ont été répertoriés afin de comparer les 2 groupes.

RÉSULTATS: Sur les 282 patients étudiés, 1 enfant dans le groupe pré-implantation et 2 enfants dans le groupe post-implantation ont eu une modification de traitement en cours de suivi (1 infection urinaire avec germe résistant dans le groupe pré-implantation et 2 bactériémies dans le groupe post-implantation). Aucun patient étudié n’a eu une évolution défavorable (choc, sepsis sévère, défaillance multiviscérale, décès) et aucune différence statistiquement significative n’a été observée dans le nombre d’échec au traitement, le taux d’hospitalisation et le nombre de visites en médecine de jour entre les 2 groupes.

CONCLUSION: Avec cette étude, nous avons démontré qu’il est sécuri-taire de ne pas administrer d’emblée un antibiotique à large spectre chez les enfants de 3 à 36 mois avec bon état général se présentant à l’urgence avec fièvre sans foyer.

Rabbit embryo-fetal fluid decreases the cell cycle activities of DU-145 cells

Successful reproduction requires tight control of cell proliferation and differentiation. Rabbit blastocoelic fluid contains such regulatory factors. For instance, it inhibits tumour or transformed cell proliferation. In this study, DU-145 cells have been used to characterize further this inhibitory activity. Maximal inhibition of cell proliferation is observed at day 12 of embryo-fetal development and this is accompanied by a strong reduction of [3H]-thymidine incorporation. DNA specific staining and analysis by flow cytometry show that cells are not stopped at any specific stage of the cell cycle. Using bromodeoxyuridine incorporation in combination with propidium iodide labelling, it has been possible to estimate the percentage of labelled cells, the duration of the S phase of the cell cycle derived from their relative movement and also the proportion of cells participating to the cell cycle. In the presence of embryonic and fetal fluids collected on day 12 (EFF D-12) the duration of the S phase and the doubling time are considerably increased and the percentage of cells participating in the cell cycle is decreased. The results also show that treatment with EFF D-12 induces the release of the cells from the monolayer. Taken altogether, these results suggest that EFF D-12 increases the duration of the cell cycle. This reduction of the mitotic activities lead up to cell death with subsequent release of cells into the culture medium.