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 on which this was validated lacked colorectal cancers (CRCs), and there is limited evidence for immunotherapy benefit 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 which 165 had evaluable plasma TMB (pTMB). Tissue sequencing was available for 108 patients. Optimal thresholds for stratifying patients based on overall survival were determined using a minimal p-value approach. This report includes the final overall survival analysis. RESULTS: Tissue TMB ≥10 mutations/Mb was not predictive of benefit from D+T compared to 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. In 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=2.44x10-06). CONCLUSION: pTMB derived from either clonal or subclonal mutations may identify a group more likely to benefit from immunotherapy, though validation is required. Tissue TMB provided no predictive utility for immunotherapy in this trial.

The association of healthcare contact days with physical function and survival in CCTG/AGITG CO.17.

INTRODUCTION: While contact days-days with healthcare contact outside home-are increasingly adopted as a measure of time toxicity and treatment burden, they could also serve as a surrogate of treatment-related harm. We sought to assess the association between contact days and patient-reported outcomes, and the prognostic ability of contact days. METHODS: We conducted a secondary analysis of CO.17 that evaluated cetuximab vs supportive care in patients with advanced colorectal cancer. CO.17 collected EORTC-QLQ-C30 instrument data. We assessed the association between number of contact days in a window and changes in physical function and global health status, and the association between number of contact days in the first 4 weeks with overall survival (OS). RESULTS: There was a negative association between the number of contact days and change in physical function (per each additional contact day at 4 weeks, 1.50 point decrease; and 8 weeks, 1.06 point decrease, p < .0001 for both), but not with global health status. This negative association was seen in patients receiving cetuximab, but not supportive care. More contact days in the first 4 weeks was associated with worse OS for all comers and patients receiving cetuximab (per each additional contact day; all comers, aHR 1.07, 95% CI, 1.05- 1.10; and cetuximab, aHR 1.08, 95%CI 1.05- 1.11, p < .0001 for both). CONCLUSIONS: In this secondary analysis of a clinical trial, more contact days early in the course was associated with declines in physical function and worse survival in all-comers and in participants receiving cancer-directed treatment. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT00079066.

Simple versus Radical Hysterectomy in Women with Low-Risk Cervical Cancer.

BACKGROUND: Retrospective data suggest that the incidence of parametrial infiltration is low in patients with early-stage low-risk cervical cancer, which raises questions regarding the need for radical hysterectomy in these patients. However, data from large, randomized trials comparing outcomes of radical and simple hysterectomy are lacking. METHODS: We conducted a multicenter, randomized, noninferiority trial comparing radical hysterectomy with simple hysterectomy including lymph-node assessment in patients with low-risk cervical cancer (lesions of ≤2 cm with limited stromal invasion). The primary outcome was cancer recurrence in the pelvic area (pelvic recurrence) at 3 years. The prespecified noninferiority margin for the between-group difference in pelvic recurrence at 3 years was 4 percentage points. RESULTS: Among 700 patients who underwent randomization (350 in each group), the majority had tumors that were stage IB1 according to the 2009 International Federation of Gynecology and Obstetrics (FIGO) criteria (91.7%), that had squamous-cell histologic features (61.7%), and that were grade 1 or 2 (59.3%). With a median follow-up time of 4.5 years, the incidence of pelvic recurrence at 3 years was 2.17% in the radical hysterectomy group and 2.52% in the simple hysterectomy group (an absolute difference of 0.35 percentage points; 90% confidence interval, -1.62 to 2.32). Results were similar in a per-protocol analysis. The incidence of urinary incontinence was lower in the simple hysterectomy group than in the radical hysterectomy group within 4 weeks after surgery (2.4% vs. 5.5%; P = 0.048) and beyond 4 weeks (4.7% vs. 11.0%; P = 0.003). The incidence of urinary retention in the simple hysterectomy group was also lower than that in the radical hysterectomy group within 4 weeks after surgery (0.6% vs. 11.0%; P<0.001) and beyond 4 weeks (0.6% vs. 9.9%; P<0.001). CONCLUSIONS: In patients with low-risk cervical cancer, simple hysterectomy was not inferior to radical hysterectomy with respect to the 3-year incidence of pelvic recurrence and was associated with a lower risk of urinary incontinence or retention. (Funded by the Canadian Cancer Society and others; ClinicalTrials.gov number, NCT01658930.).

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.

Randomized, double-blind, controlled trial of a combination of alpha-lipoic acid and pregabalin for neuropathic pain: the PAIN-CARE trial.

ABSTRACT: We compared a combination of the nonsedating antioxidant, alpha-lipoic acid (ALA), with the sedating anticonvulsant, pregabalin, vs each monotherapy to treat neuropathic pain due to peripheral neuropathies. In this randomized, double-blind, 3-period crossover trial, participants received oral ALA, pregabalin, and their combination-each for 6 weeks. The primary outcome was mean daily pain intensity at maximal tolerated doses (MTD); secondary outcomes included quality of life (SF-36), sleep (Medical Outcomes Study-Sleep Scale), adverse effects, drug doses, and other measures. Of 55 participants randomized (20-diabetic neuropathy, 19-small fiber neuropathy, and 16-other neuropathies), 46 completed 2 periods, and 44 completed 3. At MTD, the primary outcome of mean pain intensity (0-10) was 5.32 (standard error, SE = 0.18), 3.96 (0.25), 3.25 (0.25), and 3.16 (0.25) at baseline, ALA, pregabalin, and combination, respectively ( P < 0.01 for ALA vs combination and pregabalin). Treatment differences were similar in subgroups with diabetic neuropathy and with other neuropathies. SF-36 total scores (higher number indicates better quality of life) were 66.6 (1.88), 70.1 (1.88), and 69.4 (1.87) with ALA, pregabalin, and combination ( P < 0.05 for ALA vs combination and pregabalin). At MTD, there were no statistically significant treatment differences in adverse effects or drug doses. This trial demonstrates superiority of pregabalin vs ALA but provides no evidence to suggest added benefit of combining ALA with pregabalin to treat neuropathic pain.

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.

Pembrolizumab plus chemotherapy versus chemotherapy in untreated advanced pleural mesothelioma in Canada, Italy, and France: a phase 3, open-label, randomised controlled trial.

BACKGROUND: Pleural mesothelioma usually presents at an advanced, incurable stage. Chemotherapy with platinum-pemetrexed is a standard treatment. We hypothesised that the addition of pembrolizumab to platinum-pemetrexed would improve overall survival in patients with pleural mesothelioma. METHODS: We did this open-label, international, randomised phase 3 trial at 51 hospitals in Canada, Italy, and France. Eligible participants were aged 18 years or older, with previously untreated advanced pleural mesothelioma, with an Eastern Cooperative Oncology Group performance status score of 0 or 1. Patients were randomly assigned (1:1) to intravenous chemotherapy (cisplatin [75 mg/m2] or carboplatin [area under the concentration-time curve 5-6 mg/mL per min] with pemetrexed 500 mg/m2, every 3 weeks for up to 6 cycles), with or without intravenous pembrolizumab 200 mg every 3 weeks (up to 2 years). The primary endpoint was overall survival in all randomly assigned patients; safety was assessed in all randomly assigned patients who received at least one dose of study therapy. This trial is registered with ClinicalTrials.gov, NCT02784171, and is closed to accrual. FINDINGS: Between Jan 31, 2017, and Sept 4, 2020, 440 patients were enrolled and randomly assigned to chemotherapy alone (n=218) or chemotherapy with pembrolizumab (n=222). 333 (76 %) of patients were male, 347 (79%) were White, and median age was 71 years (IQR 66-75). At final analysis (database lock Dec 15, 2022), with a median follow-up of 16·2 months (IQR 8·3-27·8), overall survival was significantly longer with pembrolizumab (median overall survival 17·3 months [95% CI 14·4-21·3] with pembrolizumab vs 16·1 months [13·1-18·2] with chemotherapy alone, hazard ratio for death 0·79; 95% CI 0·64-0·98, two-sided p=0·0324). 3-year overall survival rate was 25% (95% CI 20-33%) with pembrolizumab and 17% (13-24%) with chemotherapy alone. Adverse events related to study treatment of grade 3 or 4 occurred in 60 (27%) of 222 patients in the pembrolizumab group and 32 (15%) of 211 patients in the chemotherapy alone group. Hospital admissions for serious adverse events related to one or more study drugs were reported in 40 (18%) of 222 patients in the pembrolizumab group and 12 (6%) of 211 patients in the chemotherapy alone group. Grade 5 adverse events related to one or more drugs occurred in two patients on the pembrolizumab group and one patient in the chemotherapy alone group. INTERPRETATION: In patients with advanced pleural mesothelioma, the addition of pembrolizumab to standard platinum-pemetrexed chemotherapy was tolerable and resulted in a significant improvement in overall survival. This regimen is a new treatment option for previously untreated advanced pleural mesothelioma. FUNDING: The Canadian Cancer Society and Merck & Co.

A composite semiparametric homogeneity test for the distributions of multigroup interval-bounded longitudinal data.

Motivated by comparing the distribution of longitudinal quality of life (QoL) data among different treatment groups from a cancer clinical trial, we propose a semiparametric test statistic for the homogeneity of the distributions of multigroup longitudinal measurements, which are bounded in a closed interval with excess observations taking the boundary values. Our procedure is based on a three-component mixed density ratio model and a composite empirical likelihood for the longitudinal data taking values inside the interval. A nonparametric bootstrap method is applied to calculate the p-value of the proposed test. Simulation studies are conducted to evaluate the proposed procedure, which show that the proposed test is effective in controlling type I errors and more powerful than the procedure which ignores the values on the boundaries. It is also robust to the model mispecification than the parametric test. The proposed procedure is also applied to compare the distributions of the scores of Physical Function subscale and Global Heath Status between the patients randomized to two treatment groups in a cancer clinical trial.

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.

A threshold longitudinal Tobit quantile regression model for identification of treatment-sensitive subgroups based on interval-bounded longitudinal measurements and a continuous covariate.

Identification of a subgroup of patients who may be sensitive to a specific treatment is an important problem in precision medicine. This article considers the case where the treatment effect is assessed by longitudinal measurements, such as quality of life scores assessed over the duration of a clinical trial, and the subset is determined by a continuous baseline covariate, such as age and expression level of a biomarker. Recently, a linear mixed threshold regression model has been proposed but it assumes the longitudinal measurements are normally distributed. In many applications, longitudinal measurements, such as quality of life data obtained from answers to questions on a Likert scale, may be restricted in a fixed interval because of the floor and ceiling effects and, therefore, may be skewed. In this article, a threshold longitudinal Tobit quantile regression model is proposed and a computational approach based on alternating direction method of multipliers algorithm is developed for the estimation of parameters in the model. In addition, a random weighting method is employed to estimate the variances of the parameter estimators. The proposed procedures are evaluated through simulation studies and applications to the data from clinical trials.

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.

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.

Combination analgesic development for enhanced clinical efficacy (the CADENCE trial): a double-blind, controlled trial of an alpha-lipoic acid-pregabalin combination for fibromyalgia pain.

ABSTRACT: Drug therapy for fibromyalgia is limited by incomplete efficacy and dose-limiting adverse effects (AEs). Combining agents with complementary analgesic mechanisms-and differing AE profiles-could provide added benefits. We assessed an alpha-lipoic acid (ALA)-pregabalin combination with a randomized, double-blind, 3-period crossover design. Participants received maximally tolerated doses of ALA, pregabalin, and ALA-pregabalin combination for 6 weeks. The primary outcome was daily pain (0-10); secondary outcomes included Fibromyalgia Impact Questionnaire, SF-36 survey, Medical Outcomes Study Sleep Scale, Beck Depression Inventory (BDI-II), adverse events, and other measures. The primary outcome of daily pain (0-10) during ALA (4.9), pregabalin (4.6), and combination (4.5) was not significantly different ( P = 0.54). There were no significant differences between combination and each monotherapy for any secondary outcomes, although combination and pregabalin were both superior to ALA for measures of mood and sleep. Alpha-lipoic acid and pregabalin maximal tolerated doses were similar during combination and monotherapy, and AEs were not frequent with combination therapy. These results do not support any additive benefit of combining ALA with pregabalin for fibromyalgia. The observation of similarly reached maximal tolerated drug doses of these 2 agents (which have differing side-effect profiles) during combination and monotherapy-without increased side effects-provides support for future development of potentially more beneficial combinations with complementary mechanisms and nonoverlapping side effects.

Evaluating the Time Toxicity of Cancer Treatment in the CCTG CO.17 Trial.

PURPOSE: The time spent in pursuing treatments for advanced cancer can be substantial. We have previously proposed a pragmatic and patient-centered metric of these time costs-which we term time toxicity-as any day with physical health care system contact. This includes outpatient visits (eg, bloodwork, scans, etc), emergency department visits, and overnight stays in a health care facility. Herein, we sought to assess time toxicity in a completed randomized controlled trial (RCT). METHODS: We conducted a secondary analysis of the Canadian Cancer Trials Group CO.17 RCT that evaluated weekly cetuximab infusions versus supportive care alone in 572 patients with advanced colorectal cancer. Initial results reported a 6-week improvement in median overall survival (OS) with cetuximab (6.1 v 4.6 months). Subsequent analyses reported that benefit was restricted to patients with K-ras wild-type tumors. We calculated patient-level time toxicity by analyzing trial forms. We considered days without health care contact as home days. We compared medians of time measures across arms and stratified results by K-ras status. RESULTS: In the overall population, median time toxic days were higher in the cetuximab arm (28 v 10, P < .001) although median home days were not statistically different between arms (140 v 121, P = .09). In patients with K-ras-mutated tumors, cetuximab was associated with almost numerically equal home days (114 days v 112 days, P = .571) and higher time toxicity (23 days v 11 days, P < .001). In patients with K-ras wild-type tumors, cetuximab was associated with more home days (186 v 132, P < .001). CONCLUSION: This proof-of-concept feasibility study demonstrates that measures of time toxicity can be extracted through secondary analyses of RCTs. In CO.17, despite an overall OS benefit with cetuximab, home days were statistically similar across arms. Such data can supplement traditional survival end points in RCTs. Further work should refine and validate the measure prospectively.[Media: see text].

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.

Brief Report: Canadian Cancer Trials Group IND.227: A Phase 2 Randomized Study of Pembrolizumab in Patients With Advanced Malignant Pleural Mesothelioma (NCT02784171).

Immune checkpoint inhibitors have activity in mesothelioma. IND.227 was a phase 2 trial (120 patients planned) comparing progression-free survival of standard platinum and pemetrexed (CP) versus CP + pembrolizumab (pembro) versus pembro. Accrual to the pembro arm was discontinued on the basis of interim analysis (IA-16 wk disease control rate). CP + pembro was tolerable, with progression-free survival similar between arms and median survival and overall response rate higher than those of CP alone (19.8 mo [95% confidence interval or CI: 8.4-41.36] versus 8.9 mo [95% CI: 5.3-12.8] and 47% [95% CI: 24%-71%] versus 19% [95% CI: 5%-42%], respectively). The subsequent phase 3 trial has completed accrual; results are expected in 2023.

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.