Kinetic Profiling of RAS Mutations With Circulating Tumor DNA in the Canadian Cancer Trials Group CO.26 Trial Suggests the Loss of RAS Mutations in Neo-RAS-Wildtype Metastatic Colorectal Cancer Is Transient.

PURPOSE: In metastatic colorectal cancer (mCRC), RAS mutations drive resistance to anti-epidermal growth factor receptor antibodies. It is unclear whether RAS mutations ever become clonally undetectable. METHODS: CO.26 was a phase II clinical trial that assessed durvalumab + tremelimumab in heavily pretreated mCRC. RAS mutation status was tracked over time using circulating tumor DNA (ctDNA) sequencing at baseline, week 8, and on progression. RESULTS: Among the 95 patients with KRAS/NRAS mutations in their archival tumor tissue, 6.3% (6/95) had undetectable RAS mutations in ctDNA collected at baseline or week 8 of the CO.26 study. Of these, 67% (4/6) of disappearances were transient, with the same mutation reappearing with progressive disease. In three cases, the simultaneous persistence of other preexisting CRC-associated truncal mutations could not be demonstrated, suggestive of low tumor shedding of ctDNA, leaving the incidence of true clonal reversion to RAS-wildtype (WT) possibly as low as 3.2% (3/95). Fewer patients in the neo-RAS-WT group (33%) had greater than four lesions at trial baseline compared with patients with persistent RAS mutations (75%), P = .046. The likelihood of synchronous metastases at cancer diagnosis (33% v 63%; P = .15) or liver metastases at trial baseline (50% v 68.5%; P = .17) was not significantly different between patients with disappearing versus persistent RAS mutations. Overall survival from stage IV diagnosis (hazard ratio, 0.77 [95% CI, 0.35 to 1.72]; P = .52) was not significantly different between those with disappearing versus persistent RAS mutations. The disappearance of RAS mutations was not associated with primary tumor sidedness (P = .41), archival BRAF/MEK/ERK-mutant status (P = .16/1.00/.09), nor baseline ctDNA HER2 amplifications (P = 1.00). CONCLUSION: We identified a 3.2%-6.3% prevalence of the neo-RAS-WT phenomenon in the CO.26 trial. However, 67% of apparent cases were transient with subsequent re-emergence.

Plasma versus Tissue Tumor Mutational Burden as Biomarkers of Durvalumab plus Tremelimumab Response in Patients with Metastatic Colorectal Cancer in the CO.26 Trial.

PURPOSE: Tissue-derived tumor mutation burden (TMB) of ≥10 mutations/Mb is a histology-agnostic biomarker for the immune checkpoint inhibitor (ICI) pembrolizumab. However, the dataset in which this was validated lacked colorectal cancers (CRC), and there is limited evidence for immunotherapy benefits in CRC using this threshold. PATIENTS AND METHODS: CO.26 was a randomized phase II study of 180 patients, comparing durvalumab and tremelimumab (D + T, n = 119 patients) versus best supportive care (BSC; n = 61 patients). ctDNA sequencing was available for 168 patients (n = 118 D + T; n = 50), of whom 165 had evaluable plasma TMB (pTMB). Tissue sequencing was available for 108 patients. Optimal thresholds for stratifying patients based on OS were determined using a minimal P value approach. This report includes the final OS analysis. RESULTS: Tissue TMB ≥10 mutations/Mb was not predictive of benefit from D + T compared with BSC in microsatellite stable (MSS) metastatic CRC [HR, 0.71 (95% CI, 0.28-1.80); P = 0.47]. No tissue TMB threshold could identify a high TMB group that benefited from ICI. By contrast, plasma TMB (pTMB) ≥28 mutations/Mb was predictive of benefit from D + T [HR, 0.34 (95% CI, 0.13-0.85); P = 0.022], as was clonal pTMB ≥10.6 mutations/Mb [HR, 0.10 (95% CI, 0.014-0.79); P = 0.029] and subclonal pTMB ≥25.9/Mb [HR, 0.20 (95% CI, 0.061-0.69); P = 0.010]. Higher pTMB was associated with length of time on cytotoxic agents (P = 0.021) and prior anti-EGFR exposure (P = 2.44 × 10-06). CONCLUSIONS: pTMB derived from either clonal or subclonal mutations may identify a group likely to benefit from immunotherapy, although validation is required. Tissue TMB provided no predictive utility for immunotherapy in this trial.

Marizomib for patients with newly diagnosed glioblastoma: A randomized phase 3 trial.

BACKGROUND: Standard treatment for patients with newly diagnosed glioblastoma includes surgery, radiotherapy (RT), and temozolomide (TMZ) chemotherapy (TMZ/RT→TMZ). The proteasome has long been considered a promising therapeutic target because of its role as a central biological hub in tumor cells. Marizomib is a novel pan-proteasome inhibitor that crosses the blood-brain barrier. METHODS: European Organisation for Research and Treatment of Cancer 1709/Canadian Cancer Trials Group CE.8 was a multicenter, randomized, controlled, open-label phase 3 superiority trial. Key eligibility criteria included newly diagnosed glioblastoma, age > 18 years and Karnofsky performance status > 70. Patients were randomized in a 1:1 ratio. The primary objective was to compare overall survival (OS) in patients receiving marizomib in addition to TMZ/RT→TMZ with patients receiving the only standard treatment in the whole population and in the subgroup of patients with MGMT promoter-unmethylated tumors. RESULTS: The trial was opened at 82 institutions in Europe, Canada, and the U.S. A total of 749 patients (99.9% of the planned 750) were randomized. OS was not different between the standard and the marizomib arm (median 17 vs. 16.5 months; HR = 1.04; P = .64). PFS was not statistically different either (median 6.0 vs. 6.3 months; HR = 0.97; P = .67). In patients with MGMT promoter-unmethylated tumors, OS was also not different between standard therapy and marizomib (median 14.5 vs. 15.1 months, HR = 1.13; P = .27). More CTCAE grade 3/4 treatment-emergent adverse events were observed in the marizomib arm than in the standard arm. CONCLUSIONS: Adding marizomib to standard temozolomide-based radiochemotherapy resulted in more toxicity, but did not improve OS or PFS in patients with newly diagnosed glioblastoma.

National study on the risks of COVID-19 infection for paediatric kidney transplant recipients: a retrospective, cross-sectional study.

INTRODUCTION: During the COVID-19 pandemic, evidence emerged that immunosuppressed children were less affected by COVID-19 infections compared with immunosuppressed adults. The aim of our study was to investigate how COVID-19 infections affected paediatric kidney transplant recipients (pKTR) in the UK. METHODS: Questionnaires regarding COVID-19 infection data and care of pKTR during the COVID-19 pandemic were sent to all 13 UK paediatric nephrology centres examining asymptomatic and symptomatic pKTR with positive COVID-19 PCR testing from 1 April 2020 to 1 December 2021. RESULTS: 63 pKTR who were 3.1 (range 0.1-15) years post-transplantation had COVID-19 infection with positive SARS-CoV-2 PCR RNA. Classical COVID-19 symptoms were present in half of the patients; with atypical presentations including diarrhoea (13%) and lethargy (13%) also noted, while a third of patients were asymptomatic. Eighteen patients (28%) were hospitalised including five asymptomatic patients admitted for other reasons. No patients needed ventilation or intensive care admission, and one patient received supplemental oxygen. There was evidence of acute kidney injury (AKI) in 71% of patients, but no patients needed kidney replacement therapy with haemofiltration or dialysis. CONCLUSION: We report 10.4% of the UK paediatric renal transplantation population had documented COVID-19 infections with positive SARS-CoV-2 PCR RNA with 28% of those affected requiring hospitalisation. The increased incidence of AKI, particularly after the first wave of the COVID-19 pandemic, was possibly due to increased testing. There was low morbidity and mortality compared with the adult population.

The impact of time to death in donors after circulatory death on recipient outcome in simultaneous pancreas-kidney transplantation.

The time to arrest donors after circulatory death is unpredictable and can vary. This leads to variable periods of warm ischemic damage prior to pancreas transplantation. There is little evidence supporting procurement team stand-down times based on donor time to death (TTD). We examined what impact TTD had on pancreas graft outcomes following donors after circulatory death (DCD) simultaneous pancreas-kidney transplantation. Data were extracted from the UK transplant registry from 2014 to 2022. Predictors of graft loss were evaluated using a Cox proportional hazards model. Adjusted restricted cubic spline models were generated to further delineate the relationship between TTD and outcome. Three-hundred-and-seventy-five DCD simultaneous kidney-pancreas transplant recipients were included. Increasing TTD was not associated with graft survival (adjusted hazard ratio HR 0.98, 95% confidence interval 0.68-1.41, P = .901). Increasing asystolic time worsened graft survival (adjusted hazard ratio 2.51, 95% confidence interval 1.16-5.43, P = .020). Restricted cubic spline modeling revealed a nonlinear relationship between asystolic time and graft survival and no relationship between TTD and graft survival. We found no evidence that TTD impacts pancreas graft survival after DCD simultaneous pancreas-kidney transplantation; however, increasing asystolic time was a significant predictor of graft loss. Procurement teams should attempt to minimize asystolic time to optimize pancreas graft survival rather than focus on the duration of TTD.

Transverse Colon Primary Tumor Location as a Biomarker in Metastatic Colorectal Cancer: A Pooled Analysis of CCTG/AGITG CO.17 and CO.20 Randomized Clinical Trials.

PURPOSE: Sidedness is prognostic and predictive of anti-EGFR efficacy in metastatic colorectal cancer (mCRC). Transverse colon has been historically excluded from several analyses of sidedness and the optimal division between left- and right-sided colorectal cancer is unclear. We investigated transverse colon primary tumor location as a biomarker in mCRC. EXPERIMENTAL DESIGN: Pooled analysis of CCTG/AGITG CO.17 and CO.20 trials of cetuximab in chemotherapy-refractory mCRC. Outcomes of patients with RAS/BRAF wild-type (WT) mCRC from CO.17 and KRAS WT mCRC from CO.20 were analyzed according to location. RESULTS: A total of 553 patients were analyzed, 32 (5.8%) with cancers from the transverse, 101 (18.3%) from right, and 420 from (75.9%) left colon. Transverse mCRC failed to reach significant benefit from cetuximab versus best supportive care (BSC) for overall survival [OS; median, 5.9 vs. 2.1 months; HR, 0.63; 95% confidence interval (CI), 0.28-1.42; P=0.26] and progression-free survival (PFS; median, 1.8 vs. 1.3 months; HR, 0.57; 95% CI, 0.26-1.28; P=0.16). Analyzing exclusively patients randomized to cetuximab, right-sided and transverse had comparable outcomes for OS (median, 5.6 vs. 5.9 months; HR, 0.82; 95% CI, 0.50-1.34; P=0.43) and PFS (median, 1.9 vs. 1.8 months; HR, 0.78; 95% CI, 0.49-1.26; P=0.31). Patients with left-sided mCRC had superior outcomes with cetuximab compared with transverse for OS (median, 9.7 vs. 5.9 months; HR, 0.42; 95% CI, 0.27-0.67; P=0.0002) and PFS (median, 3.8 vs. 1.8 months; HR, 0,49; 95% CI, 0.31-0.76; P=0.001). Location was not prognostic in patients treated with BSC alone. CONCLUSIONS: Transverse mCRC has comparable prognostic and predictive features with right-sided mCRC.

Liver Metastases and Immune Checkpoint Inhibitor Efficacy in Patients With Refractory Metastatic Colorectal Cancer: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Immune checkpoint inhibitors (ICIs) have limited activity in microsatellite-stable (MSS) or mismatch repair-proficient (pMMR) colorectal cancer. Recent findings suggest the efficacy of ICIs may be modulated by the presence of liver metastases (LM). Objective: To investigate the association between the presence of LM and ICI activity in advanced MSS colorectal cancer. Design, Setting, and Participants: In this secondary analysis of the Canadian Cancer Trials Group CO26 (CCTG CO.26) randomized clinical trial, patients with treatment-refractory colorectal cancer were randomized in a 2:1 fashion to durvalumab plus tremelimumab or best supportive care alone between August 10, 2016, and June 15, 2017. The primary end point was overall survival (OS) with 80% power and 2-sided α = .10. The median follow-up was 15.2 (0.2-22.0) months. In this post hoc analysis performed from February 11 to 14, 2022, subgroups were defined based on the presence or absence of LM and study treatments. Intervention: Durvalumab plus tremelimumab or best supportive care. Main Outcomes and Measures: Hazard ratios (HRs) and 90% CIs were calculated based on a stratified Cox proportional hazards regression model. Plasma tumor mutation burden at study entry was determined using a circulating tumor DNA assay. The primary end point of the study was OS, defined as the time from randomization to death due to any cause; secondary end points included progression-free survival (PFS) and disease control rate (DCR). Results: Of 180 patients enrolled (median age, 65 [IQR, 36-87] years; 121 [67.2%] men; 19 [10.6%] Asian, 151 [83.9%] White, and 10 [5.6%] other race or ethnicity), LM were present in 127 (70.6%). For patients with LM, there was a higher proportion of male patients (94 of 127 [74.0%] vs 27 of 53 [50.9%]; P = .005), and the time from initial cancer diagnosis to study entry was shorter (median, 40 [range, 8-153] vs 56 [range, 14-181] months; P = .001). Plasma tumor mutation burden was significantly higher in patients with LM. Patients without LM had significantly improved PFS with durvalumab plus tremelimumab (HR, 0.54 [90% CI, 0.35-0.96]; P = .08; P = .02 for interaction). Disease control rate was 49% (90% CI, 36%-62%) in patients without LM treated with durvalumab plus tremelimumab, compared with 14% (90% CI, 6%-38%) in those with LM (odds ratio, 5.70 [90% CI, 1.46-22.25]; P = .03). On multivariable analysis, patients without LM had significantly improved OS and PFS compared with patients with LM. Conclusions and Relevance: In this secondary analysis of the CCTG CO.26 study, the presence of LM was associated with worse outcomes for patients with advanced colorectal cancer. Patients without LM had improved PFS and higher DCR with durvalumab plus tremelimumab. Liver metastases may be associated with poor outcomes of ICI treatment in advanced colorectal cancer and should be considered in the design and interpretation of future clinical studies evaluating this therapy.

Plasma Cetuximab Concentrations Correlate With Survival in Patients With Advanced KRAS Wild Type Colorectal Cancer.

BACKGROUND: Cetuximab is a standard of care therapy for patients with RAS wild-type (WT) advanced colorectal cancer. Limited data suggest a wide variation in cetuximab plasma concentrations after standard dosing regimens. We correlated cetuximab plasma concentrations with survival and toxicity. METHODS: The CO. 20 study randomized patients with RAS WT advanced colorectal cancer in a 1:1 ratio to cetuximab 400 mg/m2 intravenously followed by weekly maintenance of 250 mg/m2, plus brivanib 800 mg orally daily or placebo. Blood samples obtained at week 5 precetuximab treatment were analyzed by ELISA. Patients were grouped into tertiles based on plasma cetuximab concentrations. Cetuximab concentration tertiles were correlated with survival outcomes and toxicity. Patient demographic and biochemical parameters were evaluated as co-variables. RESULTS: Week 5 plasma cetuximab concentrations were available for 591 patients (78.8%). The median overall survival (OS) was 11.4 months and 7.8 months for patients in the highest (T3) and lowest tertiles (T1) respectively. On multivariable analysis, plasma cetuximab concentration was associated with OS (HR 0.66, 95% confidence interval [CI]: 0.53-0.83, P < .001, T3 vs. T1), and a trend towards progression-free survival (HR 0.82, 95% CI: 0.66-1.02, P = .07, T3 vs. T1). There was no association between cetuximab concentration and skin toxicity or diarrhea. CONCLUSION: The standard cetuximab dosing regimen may not be optimal for all patients. Further pharmacokinetic studies are needed to optimize cetuximab dosing given the potential improvement in OS.

The Feasibility of Quality Assurance in the TOPGEAR International Phase 3 Clinical Trial of Neoadjuvant Chemoradiation Therapy for Gastric Cancer (an Intergroup Trial of the AGITG/TROG/NHMRC CTC/EORTC/CCTG).

PURPOSE: The TOPGEAR phase 3 trial hypothesized that adding preoperative chemoradiation therapy (CRT) to perioperative chemotherapy will improve survival in patients with gastric cancer. Owing to the complexity of gastric irradiation, a comprehensive radiation therapy quality assurance (RTQA) program was implemented. Our objective is to describe the RTQA methods and outcomes. METHODS AND MATERIALS: RTQA was undertaken in real time before treatment for the first 5 patients randomized to CRT from each center. Once acceptable quality was achieved, RTQA was completed for one-third of subsequent cases. RTQA consisted of evaluating (1) clinical target volume and organ-at-risk contouring and (2) radiation therapy planning parameters. Protocol violations between high- (20+ patients enrolled) and low-volume centers were compared using the Fisher exact test. RESULTS: TOPGEAR enrolled 574 patients, of whom 286 were randomized to receive preoperative CRT and 203 (71%) were included for RTQA. Of these, 67 (33%) and 136 (67%) patients were from high- and low-volume centers, respectively. The initial RTQA pass rate was 72%. In total, 28% of cases required resubmission. In total, 200 of 203 cases (99%) passed RTQA before treatment. Cases from low-volume centers required resubmission more often (44/136 [33%] vs 13/67 [18%]; P = .078). There was no change in the proportion of cases requiring resubmission over time. Most cases requiring resubmission had multiple protocol violations. At least 1 aspect of the clinical target volume had to be adjusted in all cases. Inadequate coverage of the duodenum was most common (53% major violation, 25% minor violation). For the remaining cases, the resubmission process was triggered secondary to poor contour/plan quality. CONCLUSIONS: In a large multicenter trial, RTQA is feasible and effective in achieving high-quality treatment plans. Ongoing education should be performed to ensure consistent quality during the entire study period.

Two-stage multivariate Mendelian randomization on multiple outcomes with mixed distributions.

In clinical research, it is important to study whether certain clinical factors or exposures have causal effects on clinical and patient-reported outcomes such as toxicities, quality of life, and self-reported symptoms, which can help improve patient care. Usually, such outcomes are recorded as multiple variables with different distributions. Mendelian randomization (MR) is a commonly used technique for causal inference with the help of genetic instrumental variables to deal with observed and unobserved confounders. Nevertheless, the current methodology of MR for multiple outcomes only focuses on one outcome at a time, meaning that it does not consider the correlation structure of multiple outcomes, which may lead to a loss of statistical power. In situations with multiple outcomes of interest, especially when there are mixed correlated outcomes with different distributions, it is much more desirable to jointly analyze them with a multivariate approach. Some multivariate methods have been proposed to model mixed outcomes; however, they do not incorporate instrumental variables and cannot handle unmeasured confounders. To overcome the above challenges, we propose a two-stage multivariate Mendelian randomization method (MRMO) that can perform multivariate analysis of mixed outcomes using genetic instrumental variables. We demonstrate that our proposed MRMO algorithm can gain power over the existing univariate MR method through simulation studies and a clinical application on a randomized Phase III clinical trial study on colorectal cancer patients.

Clinical and metabolomic characterization of Brivanib-Induced hypertension in metastatic colorectal cancer.

BACKGROUND: Trials of tyrosine kinase inhibitors (TKI) have not demonstrated dramatic benefits in advanced colorectal cancer (CRC), and this may be a function of poor patient selection. TKI-induced hypertension is reportedly a surrogate marker for treatment benefit for some tumor types. Our objective was to determine whether hypertension was associated with benefit in the context of CRC treatment, and also to gain insight on the pathogenesis of TKI-induced hypertension by monitoring associated changes in the circulating metabolome. PATIENTS AND METHODS: Clinical data were acquired from clinical trial patients with metastatic CRC randomized to cetuximab ± the TKI brivanib (N = 750). Outcomes were evaluated as a function of treatment-induced hypertension. For metabolomic studies, plasma samples were taken at baseline, as well as at 1, 4, and 12 weeks after treatment initiation. Samples were submitted to gas chromatography-mass spectrometry to identify treatment-related metabolomic changes associated with TKI-induced hypertension, compared to pre-treatment baseline. A model based on changes in metabolite concentrations was generated using orthogonal partial least squares discriminant analysis (OPLS-DA). RESULTS: In the brivanib treated group, 95 patients had treatment-related hypertension within 12 weeks of initiating treatment. TKI-induced hypertension was not associated with a significantly higher response rate, nor was it associated with improved progression-free or overall survival. In metabolomic studies, 386 metabolites were identified. There were 29 metabolites that changed with treatment and distinguished patients with and without TKI-induced hypertension. The OPLS-DA model for brivanib-induced hypertension was significant and robust (R2 Y score = 0.89, Q2 Y score = 0.70, CV-ANOVA = 2.01 e-7). Notable metabolomic features previously reported in pre-eclampsia and associated with vasoconstriction were found. CONCLUSION: TKI-induced hypertension was not associated with clinical benefit in metastatic CRC. We have identified changes in the metabolome that are associated with the development of worsening brivanib-induced hypertension that may be useful in future efforts of characterizing this toxicity.

Optimizing the number of variants tracked to follow disease burden with circulating tumor DNA assays in metastatic colorectal cancer.

Background: The number of somatic mutations detectable in circulating tumor DNA (ctDNA) is highly heterogeneous in metastatic colorectal cancer (mCRC). The optimal number of mutations required to assess disease kinetics is relevant and remains poorly understood. Objectives: To determine whether increasing panel breadth (the number of tracked variants in a ctDNA assay) would alter the sensitivity in detecting ctDNA in patients with mCRC. Design: We used archival tissue sequencing to perform an in silico assessment of the optimal number of tracked mutations to detect and monitor disease kinetics in mCRC using sequencing data from the Canadian Cancer Trials Group CO.26 trial. Methods: For each patient, 1, 2, 4, 8, 12, or 16 of the most clonal (highest variant allele frequency) somatic variants were selected from archival tissue-based whole-exome sequencing and assessed for the proportion of variants detected in matched ctDNA at baseline, week 8, and progression timepoints. Results: Data from 110 patients were analyzed. Genes most frequently encountered among the top four highest VAF variants in archival tissue were TP53 (51.9% of patients), APC (43.3%), KRAS (42.3%), and SMAD4 (9.6%). While the frequency of detecting at least one tracked variant increased when expanding beyond variant pool sizes of 1 and 2 in baseline (p = 0.0030) and progression (p = 0.0030) ctDNA samples, we observed no significant benefit to increases in variant pool size past four variants in any of the ctDNA timepoints (p < 0.05). Conclusion: While increasing panel breadth beyond two tracked variants improved variant re-detection in ctDNA samples from patients with treatment refractory mCRC, increases beyond four tracked variants yielded no significant improvement in variant re-detection.

Beyond donation to organ utilization in the UK.

PURPOSE OF REVIEW: Optimizing deceased donor organ utilization is gaining recognition as a topical and important issue, both in the United Kingdom (UK) and globally. This review discusses pertinent issues in the field of organ utilization, with specific reference to UK data and recent developments within the UK. RECENT FINDINGS: A multifaceted approach is likely required in order to improve organ utilization. Having a solid evidence-base upon which transplant clinicians and patients on national waiting lists can base decisions regarding organ utilization is imperative in order to bridge gaps in knowledge regarding the optimal use of each donated organ. A better understanding of the risks and benefits of the uses of higher risk organs, along with innovations such as novel machine perfusion technologies, can help clinician decision-making and may ultimately reduce the unnecessary discard of precious deceased donor organs. SUMMARY: The issues facing the UK with regards to organ utilization are likely to be similar to those in many other developed countries. Discussions around these issues within organ donation and transplantation communities may help facilitate shared learning, lead to improvements in the usage of scarce deceased donor organs, and enable better outcomes for patients waiting for transplants.

Organ Transplants From Deceased Donors With Primary Brain Tumors and Risk of Cancer Transmission.

Importance: Cancer transmission is a known risk for recipients of organ transplants. Many people wait a long time for a suitable transplant; some never receive one. Although patients with brain tumors may donate their organs, opinions vary on the risks involved. Objective: To determine the risk of cancer transmission associated with organ transplants from deceased donors with primary brain tumors. Key secondary objectives were to investigate the association that donor brain tumors have with organ usage and posttransplant survival. Design, Setting, and Participants: This was a cohort study in England and Scotland, conducted from January 1, 2000, to December 31, 2016, with follow-up to December 31, 2020. This study used linked data on deceased donors and solid organ transplant recipients with valid national patient identifier numbers from the UK Transplant Registry, the National Cancer Registration and Analysis Service (England), and the Scottish Cancer Registry. For secondary analyses, comparators were matched on factors that may influence the likelihood of organ usage or transplant failure. Statistical analysis of study data took place from October 1, 2021, to May 31, 2022. Exposures: A history of primary brain tumor in the organ donor, identified from all 3 data sources using disease codes. Main Outcomes and Measures: Transmission of brain tumor from the organ donor into the transplant recipient. Secondary outcomes were organ utilization (ie, transplant of an offered organ) and survival of kidney, liver, heart, and lung transplants and their recipients. Key covariates in donors with brain tumors were tumor grade and treatment history. Results: This study included a total of 282 donors (median [IQR] age, 42 [33-54] years; 154 females [55%]) with primary brain tumors and 887 transplants from them, 778 (88%) of which were analyzed for the primary outcome. There were 262 transplants from donors with high-grade tumors and 494 from donors with prior neurosurgical intervention or radiotherapy. Median (IQR) recipient age was 48 (35-58) years, and 476 (61%) were male. Among 83 posttransplant malignancies (excluding NMSC) that occurred over a median (IQR) of 6 (3-9) years in 79 recipients of transplants from donors with brain tumors, none were of a histological type matching the donor brain tumor. Transplant survival was equivalent to that of matched controls. Kidney, liver, and lung utilization were lower in donors with high-grade brain tumors compared with matched controls. Conclusions and Relevance: Results of this cohort study suggest that the risk of cancer transmission in transplants from deceased donors with primary brain tumors was lower than previously thought, even in the context of donors that are considered as higher risk. Long-term transplant outcomes are favorable. These results suggest that it may be possible to safely expand organ usage from this donor group.

A Bayesian approach for two-stage multivariate Mendelian randomization with mixed outcomes.

Many research studies have investigated the relationship between baseline factors or exposures, such as patient demographic and disease characteristics, and study outcomes such as toxicities or quality of life, but results from most of these studies may be problematic because of potential confounding effects (eg, the imbalance in baseline factors or exposures). It is important to study whether the baseline factors or exposures have causal effects on the clinical outcomes, so that clinicians can have better understanding of the diseases and develop personalized medicine. Mendelian randomization (MR) provides an efficient way to estimate the causal effects using genetic instrumental variables to handle confounders, but most of the existing studies focus on a single outcome at a time and ignores the correlation structure of multiple outcomes. Given that clinical outcomes like toxicities and quality of life are usually a mixture of different types of variables, and multiple datasets may be available for such outcomes, it may be much more beneficial to analyze them jointly instead of separately. Some well-established methods are available for building multivariate models on mixed outcomes, but they do not incorporate MR mechanism to deal with the confounders. To overcome these challenges, we propose a Bayesian-based two-stage multivariate MR method for mixed outcomes on multiple datasets, called BMRMO. Using simulation studies and clinical applications on the CO.17 and CO.20 studies, we demonstrate better performance of our approach compared to the commonly used univariate two-stage method.

Vaccine Effectiveness Against the SARS-CoV-2 B.1.1.529 Omicron Variant in Solid Organ and Islet Transplant Recipients in England: A National Retrospective Cohort Study.

BACKGROUND: The effectiveness of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 Omicron variant in immunosuppressed solid organ and islet transplant (SOT) recipients is unclear. METHODS: National registries in England were linked to identify SARS-CoV-2 positive tests, noninjury hospitalization within 14 d, and deaths within 28 d between December 7, 2020, and March 31, 2022 in adult SOT recipients. Incidence rate ratios (IRRs) for infection, and hospitalization or death, were adjusted for recipient demographics and calendar month for the Omicron-dominant period (December 20, 2021, to March 31, 2022). Mortality risk following SARS-CoV-2 infection was adjusted for recipient demographics and dominant variant using a Cox proportional-hazards model for the entire time period. RESULTS: During the Omicron-dominant period, infection IRRs (95% confidence intervals) were higher in those receiving 2, 3, and 4 vaccine doses than in unvaccinated patients (1.25 [1.08-1.45], 1.46 [1.28-1.67], and 1.79 [1.54-2.06], respectively). However, hospitalization or death IRRs during this period were lower in those receiving 3 or 4 vaccine doses than in unvaccinated patients (0.62 [0.45-0.86] and 0.39 [0.26-0.58], respectively). Risk-adjusted analyses for deaths after SARS-CoV-2 infection between December 7, 2020, and March 31, 2022, found hazard ratios (95% confidence intervals) of 0.67 (0.46-0.98), 0.46 (0.30-0.69), and 0.18 (0.09-0.35) for those with 2, 3, and 4 vaccine doses, respectively, when compared with the unvaccinated group. CONCLUSIONS: In immunosuppressed SOT recipients, vaccination is associated with incremental, dose-dependent protection against hospitalization or death after SARS-CoV-2 infection, including against the Omicron variant.

Clustering on longitudinal quality-of-life measurements using growth mixture models for clinical prognosis: Implementation on CCTG/AGITG CO.20 trial.

INTRODUCTION: Analyzing longitudinal cancer quality-of-life (QoL) measurements and their impact on clinical outcomes may improve our understanding of patient trajectories during systemic therapy. We applied an unsupervised growth mixture modeling (GMM) approach to identify unobserved subpopulations ("patient clusters") in the CO.20 clinical trial longitudinal QoL data. Classes were then evaluated for differences in clinico-epidemiologic characteristics and overall survival (OS). METHODS AND MATERIALS: In CO.20, 750 chemotherapy-refractory metastatic colorectal cancer (CRC) patients were randomized to receive Brivanib+Cetuximab (n = 376, experimental arm) versus Cetuximab+Placebo (n = 374, standard arm) for 16 weeks. EORTC-QLQ-C30 QoL summary scores were calculated for each patient at seven time points, and GMM was applied to identify patient clusters (termed "classes"). Log-rank/Kaplan-Meier and multivariable Cox regression analyses were conducted to analyze the survival performance between classes. Cox analyses were used to explore the relationship between baseline QoL, individual slope, and the quadratic terms from the GMM output with OS. RESULTS: In univariable analysis, the linear mixed effect model (LMM) identified sex and ECOG Performance Status as strongly associated with the longitudinal QoL score (p < 0.01). The patients within each treatment arm were clustered into three distinct QoL-based classes by GMM, respectively. The three classes identified in the experimental (log-rank p-value = 0.00058) and in the control arms (p < 0.0001) each showed significantly different survival performance. The GMM's baseline, slope, and quadratic terms were each significantly associated with OS (p < 0.001). CONCLUSION: GMM can be used to analyze longitudinal QoL data in cancer studies, by identifying unobserved subpopulations (patient clusters). As demonstrated by CO.20 data, these classes can have important implications, including clinical prognostication.

Circulating Tumor DNA Identifies Diverse Landscape of Acquired Resistance to Anti-Epidermal Growth Factor Receptor Therapy in Metastatic Colorectal Cancer.

PURPOSE: Anti-epidermal growth factor receptor (EGFR) antibodies are effective treatments for metastatic colorectal cancer. Improved understanding of acquired resistance mechanisms may facilitate circulating tumor DNA (ctDNA) monitoring, anti-EGFR rechallenge, and combinatorial strategies to delay resistance. METHODS: Patients with treatment-refractory metastatic colorectal cancer (n = 169) enrolled on the CO.26 trial had pre-anti-EGFR tissue whole-exome sequencing (WES) compared with baseline and week 8 ctDNA assessments with the GuardantOMNI assay. Acquired alterations were compared between patients with prior anti-EGFR therapy (n = 66) and those without. Anti-EGFR therapy occurred a median of 111 days before ctDNA assessment. RESULTS: ctDNA identified 12 genes with increased mutation frequency after anti-EGFR therapy, including EGFR (P = .0007), KRAS (P = .0017), LRP1B (P = .0046), ZNF217 (P = .0086), MAP2K1 (P = .018), PIK3CG (P = .018), BRAF (P = .048), and NRAS (P = .048). Acquired mutations appeared as multiple concurrent subclonal alterations, with most showing decay over time. Significant increases in copy-gain frequency were noted in 29 genes after anti-EGFR exposure, with notable alterations including EGFR (P < .0001), SMO (P < .0001), BRAF (P < .0001), MET (P = .0002), FLT3 (P = .0002), NOTCH4 (P = .0006), ERBB2 (P = .004), and FGFR1 (P = .006). Copy gains appeared stable without decay 8 weeks later. There were 13 gene fusions noted among 11 patients, all but one of which was associated with prior anti-EGFR therapy. Polyclonal resistance was common with acquisition of ≥ 10 resistance related alterations noted in 21% of patients with previous anti-EGFR therapy compared with 5% in those without (P = .010). Although tumor mutation burden (TMB) did not differ pretreatment (P = .63), anti-EGFR exposure increased TMB (P = .028), whereas lack of anti-EGFR exposure resulted in declining TMB (P = .014). CONCLUSION: Paired tissue and ctDNA sequencing identified multiple novel mutations, copy gains, and fusions associated with anti-EGFR therapy that frequently co-occur as subclonal alterations in the same patient.

Neoadjuvant Chemotherapy, Excision, and Observation for Early Rectal Cancer: The Phase II NEO Trial (CCTG CO.28) Primary End Point Results.

PURPOSE: Organ-sparing therapy for early-stage I/IIA rectal cancer is intended to avoid functional disturbances or a permanent ostomy associated with total mesorectal excision (TME). The objective of this phase II trial was to determine the outcomes and organ-sparing rate of patients with early-stage rectal cancer treated with neoadjuvant chemotherapy followed by transanal excision surgery (TES). METHODS: This phase II trial included patients with clinical T1-T3abN0 low- or mid-rectal adenocarcinoma eligible for endoscopic resection who were treated with 3 months of chemotherapy (modified folinic acid-fluorouracil-oxaliplatin 6 or capecitabine-oxaliplatin). Those with evidence of response proceeded to transanal endoscopic surgery 2-6 weeks later. The primary end point was protocol-specified organ preservation rate, defined as the proportion of patients with tumor downstaging to ypT0/T1N0/X and who avoided radical surgery. RESULTS: Of 58 patients enrolled, all commenced chemotherapy and 56 proceeded to surgery. A total of 33/58 patients had tumor downstaging to ypT0/1N0/X on the surgery specimen, resulting in an intention-to-treat protocol-specified organ preservation rate of 57% (90% CI, 45 to 68). Of 23 remaining patients recommended for TME surgery on the basis of protocol requirements, 13 declined and elected to proceed directly to observation resulting in 79% (90% CI, 69 to 88) achieving organ preservation. The remaining 10/23 patients proceeded to recommended TME of whom seven had no histopathologic residual disease. The 1-year and 2-year locoregional relapse-free survival was, respectively, 98% (95% CI, 86 to 100) and 90% (95% CI, 58 to 98), and there were no distant recurrences or deaths. Minimal change in quality of life and rectal function scores was observed. CONCLUSION: Three months of induction chemotherapy may successfully downstage a significant proportion of patients with early-stage rectal cancer, allowing well-tolerated organ-preserving surgery.