Neoadjuvant and adjuvant pembrolizumab plus chemotherapy in locally advanced gastric or gastro-oesophageal cancer (KEYNOTE-585): an interim analysis of the multicentre, double-blind, randomised phase 3 study.

BACKGROUND: The benefit of combination neoadjuvant and adjuvant chemotherapy and immune checkpoint inhibition in patients with locally advanced, resectable gastric or gastro-oesophageal adenocarcinoma is unknown. We assess the antitumor activity of neoadjuvant and adjuvant pembrolizumab plus chemotherapy in patients with locally advanced resectable gastric or gastro-oesophageal adenocarcinoma. METHODS: The KEYNOTE-585 study is a multicentre, randomised, placebo-controlled, double-blind, phase 3 study done at 143 medical centres in 24 countries. Eligible patients were aged 18 years or older with untreated, locally advanced, resectable gastric or gastro-oesophageal adenocarcinoma, and an Eastern Cooperative Oncology Group performance status 0-1. Patients were randomly assigned (1:1) by an interactive voice response system and integrated web response system to neoadjuvant pembrolizumab 200 mg intravenously or placebo (saline) plus cisplatin-based doublet chemotherapy (main cohort) every 3 weeks for 3 cycles, followed by surgery, adjuvant pembrolizumab or placebo plus chemotherapy for 3 cycles, then adjuvant pembrolizumab or placebo for 11 cycles. A small cohort was also randomly assigned (1:1) to pembrolizumab or placebo plus fluorouracil, docetaxel, and oxaliplatin (FLOT)-based chemotherapy (FLOT cohort) every 2 weeks for four cycles, followed by surgery, adjuvant pembrolizumab, or placebo plus FLOT for four cycles, then adjuvant pembrolizumab or placebo for 11 cycles. Patients were stratified by geographic region, tumour stage, and chemotherapy backbone. Primary endpoints were pathological complete response (reviewed centrally), event-free survival (reviewed by the investigator), and overall survival in the intention-to-treat population, and safety assessed in all patients who received at least one dose of study treatment. The study is registered at ClinicalTrials.gov, NCT03221426, and is closed to accrual. FINDINGS: Between Oct 9, 2017, and Jan 25, 2021, of 1254 patients screened, 804 were randomly assigned to the main cohort, of whom 402 were assigned to the pembrolizumab plus cisplatin-based chemotherapy group and 402 to the placebo plus cisplatin-based chemotherapy group, and 203 to the FLOT cohort, of whom 100 were assigned to the pembrolizumab plus FLOT group and 103 to placebo plus FLOT group. In the main cohort of 804 participants, 575 (72%) were male and 229 (28%) were female. In the main cohort, after median follow-up of 47·7 months (IQR 38·0-54·8), pembrolizumab was superior to placebo for pathological complete response (52 [12·9%; 95% CI 9·8-16·6] of 402 vs eight [2·0%; 0·9-3·9] of 402; difference 10·9%, 95% CI 7·5 to 14·8; p<0·00001). Median event-free survival was longer with pembrolizumab versus placebo (44·4 months, 95% CI 33·0 to not reached vs 25·3 months, 20·6 to 33·9; hazard ratio [HR] 0·81, 95% CI 0·67 to 0·99; p=0·0198) but did not meet the threshold for statistical significance (p=0·0178). Median overall survival was 60·7 months (95% CI 51·5 to not reached) in the pembrolizumab group versus 58·0 months (41·5 to not reached) in the placebo group (HR 0·90, 95% CI 0·73 to 1·12; p=0·174). Grade 3 or worse adverse events of any cause occurred in 312 (78%) of 399 patients in the pembrolizumab group and 297 (74%) of 400 patients in the placebo group; the most common were nausea (240 [60%] vs 247 [62%]), anaemia (168 [42%] vs 158 [40%]), and decreased appetite (163 [41%] vs 172 [43%]). Treatment-related serious adverse events were reported in 102 (26%) and 97 (24%) patients. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group (interstitial ischaemia, pneumonia, decreased appetite, and acute kidney injury [n=1 each]) and two (<1%) patients in the placebo group (neutropenic sepsis and neutropenic colitis [n=1 each]). INTERPRETATION: Although neoadjuvant and adjuvant pembrolizumab versus placebo improved the pathological complete response, it did not translate to significant improvement in event-free survival in patients with untreated, locally advanced resectable gastric or gastro-oesophageal cancer. FUNDING: Merck Sharp & Dohme.

Pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma: interim analyses from the phase 3 KEYNOTE-811 randomised placebo-controlled trial.

BACKGROUND: Evidence for the efficacy of combined PD-1 and HER2 blockade with chemotherapy on progression-free and overall survival in HER2-positive gastro-oesophageal cancer is scarce. The first interim analysis of the randomised, phase 3 KEYNOTE-811 study showed a superior objective response with pembrolizumab compared with placebo when added to trastuzumab plus fluoropyrimidine and platinum-based chemotherapy. Here, we report results from protocol-specified subsequent interim analyses of KEYNOTE-811. METHODS: The randomised, phase 3 KEYNOTE-811 trial involved 168 medical centres in 20 countries worldwide. Patients aged 18 years or older with locally advanced or metastatic HER2-positive gastro-oesophageal junction adenocarcinoma, without previous first-line treatment, were randomly assigned (1:1) by an integrated interactive voice-response and web-response system to intravenous pembrolizumab 200 mg or placebo, both to be combined with standard chemotherapy (fluoropyrimidine and platinum-based therapy) plus trastuzumab every 3 weeks for up to 35 cycles or until disease progression, unacceptable toxic effects, or investigator or participant-initiated withdrawal. Randomisation used a block size of four and was stratified by region, PD-L1 status, and chemotherapy. Dual primary endpoints were progression-free and overall survival, analysed by intention to treat. Safety was assessed in all randomly assigned patients who received at least one dose of study treatment according to the treatment received. KEYNOTE-811 is registered with ClinicalTrials.gov (NCT03615326) and is active but not recruiting. FINDINGS: Between Oct 5, 2018, and Aug 6, 2021, 698 patients were assigned to pembrolizumab (n=350) or placebo (n=348). 564 (81%) were male and 134 (19%) were female. At the third interim analysis, 286 (82%) of 350 patients in the pembrolizumab group and 304 (88%) of 346 in the placebo group who received treatment had discontinued treatment, mostly due to disease progression. At the second interim analysis (median follow-up 28·3 months [IQR 19·4-34·3] in the pembrolizumab group and 28·5 months [20·1-34·3] in the placebo group), median progression-free survival was 10·0 months (95% CI 8·6-11·7) in the pembrolizumab group versus 8·1 months (7·0-8·5) in the placebo group (hazard ratio [HR] 0·72, 95% CI 0·60-0·87; p=0·0002). Median overall survival was 20·0 months (17·8-23·2) versus 16·9 months (15·0-19·8; HR 0·87 [0·72-1·06]; p=0·084). At the third interim analysis (median follow-up 38·4 months [IQR 29·5-44·4] in the pembrolizumab group and 38·6 months [30·2-44·4] in the placebo group), median progression-free survival was 10·0 months (8·6-12·2) versus 8·1 months (7·1-8·6; HR 0·73 [0·61-0·87]), and median overall survival was 20·0 months (17·8-22·1) versus 16·8 months (15·0-18·7; HR 0·84 [0·70-1·01]), but did not meet prespecified criteria for significance and will continue to final analysis. Grade 3 or worse treatment-related adverse events occurred in 204 (58%) of 350 patients in the pembrolizumab group versus 176 (51%) of 346 patients in the placebo group. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group and three (1%) in the placebo group. The most common treatment-related adverse events of any grade were diarrhoea (165 [47%] in the pembrolizumab group vs 145 [42%] in the placebo group), nausea (154 [44%] vs 152 [44%]), and anaemia (109 [31%] vs 113 [33%]). INTERPRETATION: Compared with placebo, pembrolizumab significantly improved progression-free survival when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer, specifically in patients with tumours with a PD-L1 combined positive score of 1 or more. Overall survival follow-up is ongoing and will be reported at the final analysis. FUNDING: Merck Sharp & Dohme.

Association between gene expression signatures and clinical outcomes of pembrolizumab versus paclitaxel in advanced gastric cancer: exploratory analysis from the randomized, controlled, phase III KEYNOTE-061 trial.

BACKGROUND: In the randomized, controlled, phase III KEYNOTE-061 trial, second-line pembrolizumab did not significantly prolong overall survival (OS) versus paclitaxel in patients with PD-L1-positive (combined positive score ≥1) advanced gastric/gastroesophageal junction (G/GEJ) cancer but did elicit a longer duration of response and offered a favorable safety profile. This prespecified exploratory analysis was conducted to evaluate associations between tumor gene expression signatures and clinical outcomes in the phase III KEYNOTE-061 trial. METHODS: Using RNA sequencing data obtained from formalin-fixed, paraffin-embedded baseline tumor tissue samples, we evaluated the 18-gene T-cell-inflamed gene expression profile (TcellinfGEP) and 10 non-TcellinfGEP signatures (angiogenesis, glycolysis, granulocytic myeloid-derived suppressor cell (gMDSC), hypoxia, monocytic MDSC (mMDSC), MYC, proliferation, RAS, stroma/epithelial-to-mesenchymal transition/transforming growth factor-ß, WNT). The association between each signature on a continuous scale and outcomes was analyzed using logistic (objective response rate (ORR)) and Cox proportional hazards regression (progression-free survival (PFS) and OS). One-sided (pembrolizumab) and two-sided (paclitaxel) p values were calculated for TcellinfGEP (prespecified α=0.05) and the 10 non-TcellinfGEP signatures (multiplicity-adjusted; prespecified α=0.10). RESULTS: RNA sequencing data were available for 137 patients in each treatment group. TcellinfGEP was positively associated with ORR (p=0.041) and PFS (p=0.026) for pembrolizumab but not paclitaxel (p>0.05). The TcellinfGEP-adjusted mMDSC signature was negatively associated with ORR (p=0.077), PFS (p=0.057), and OS (p=0.033) for pembrolizumab, while the TcellinfGEP-adjusted glycolysis (p=0.018), MYC (p=0.057), and proliferation (p=0.002) signatures were negatively associated with OS for paclitaxel. CONCLUSIONS: This exploratory analysis of tumor TcellinfGEP showed associations with ORR and PFS for pembrolizumab but not for paclitaxel. TcellinfGEP-adjusted mMDSC signature was negatively associated with ORR, PFS, and OS for pembrolizumab but not paclitaxel. These data suggest myeloid-driven suppression may play a role in resistance to PD-1 inhibition in G/GEJ cancer and support a strategy of considering immunotherapy combinations which target this myeloid axis. TRIAL REGISTRATION NUMBER: NCT02370498.

Event-Free Survival as a Surrogate for Overall Survival in Gastric and Gastroesophageal Junction Adenocarcinoma: A Meta-analysis in the Neoadjuvant ± Adjuvant Setting.

PURPOSE: This study assessed the trial-level association between event-free survival (EFS) and overall survival (OS) in gastric or gastroesophageal junction (GEJ) adenocarcinoma in the neoadjuvant ± adjuvant settings. EXPERIMENTAL DESIGN: A systematic literature review was conducted to identify randomized controlled trials (RCT) that evaluated neoadjuvant therapies with or without adjuvant therapies for gastric or GEJ adenocarcinoma. A meta-analysis was performed using weighted linear regressions of the treatment effect of OS on the treatment effect of EFS. The coefficient of determination (R²) and associated 95% confidence interval (CI) were used to evaluate the association between treatment effects of EFS and OS. The threshold used for defining good trial-level surrogacy was a correlation coefficient (R) of 0.8 or R² of 0.65, based on prior literature. Sensitivity analyses were performed to assess the robustness of the association with divergent study designs, including study population, inclusion of adjuvant therapy, and definitions of EFS and OS. RESULTS: The main analysis included 16 comparisons from 15 RCTs. The log(HR) of EFS was a significant predictor of log(HR) of OS, with an estimated coefficient of 0.72 (P < 0.001) and R² = 0.75 (95% CI, 0.49-0.95), indicating that EFS was a good surrogate outcome for OS. The results of the sensitivity analyses were consistent with the primary results, with R² ranging from 0.76 to 0.89. CONCLUSIONS: This study suggests that EFS is a good surrogate for OS in gastric or GEJ adenocarcinoma in the neoadjuvant ± adjuvant setting.

Characteristics of children ≤36 months of age with DIPG: A report from the international DIPG registry.

BACKGROUND: Children ≤36 months with diffuse intrinsic pontine glioma (DIPG) have increased long-term survival (LTS, overall survival (OS) ≥24 months). Understanding distinguishing characteristics in this population is critical to improving outcomes. METHODS: Patients ≤36 months at diagnosis enrolled on the International DIPG Registry (IDIPGR) with central imaging confirmation were included. Presentation, clinical course, imaging, pathology and molecular findings were analyzed. RESULTS: Among 1183 patients in IDIPGR, 40 were eligible (median age: 29 months). Median OS was 15 months. Twelve patients (30%) were LTS, 3 (7.5%) very long-term survivors ≥5 years. Among 8 untreated patients, median OS was 2 months. Patients enrolled in the registry but excluded from our study by central radiology review or tissue diagnosis had median OS of 7 months. All but 1 LTS received radiation. Among 32 treated patients, 1-, 2-, 3-, and 5-year OS rates were 68.8%, 31.2%, 15.6% and 12.5%, respectively. LTS had longer duration of presenting symptoms (P = .018). No imaging features were predictive of outcome. Tissue and genomic data were available in 18 (45%) and 10 patients, respectively. Among 9 with known H3K27M status, 6 had a mutation. CONCLUSIONS: Children ≤36 months demonstrated significantly more LTS, with an improved median OS of 15 months; 92% of LTS received radiation. Median OS in untreated children was 2 months, compared to 17 months for treated children. LTS had longer duration of symptoms. Excluded patients demonstrated a lower OS, contradicting the hypothesis that children ≤36 months with DIPG show improved outcomes due to misdiagnosis.

Pembrolizumab versus paclitaxel for previously treated PD-L1-positive advanced gastric or gastroesophageal junction cancer: 2-year update of the randomized phase 3 KEYNOTE-061 trial.

BACKGROUND: In the phase 3 KEYNOTE-061 study (cutoff: 10/26/2017), pembrolizumab did not significantly prolong OS vs paclitaxel as second-line (2L) therapy in PD-L1 combined positive score (CPS) ≥ 1 gastric/GEJ cancer. We present results in CPS ≥ 1, ≥ 5, and ≥ 10 populations after two additional years of follow-up (cutoff: 10/07/2019). METHODS: Patients were randomly allocated 1:1 to pembrolizumab 200 mg Q3W for ≤ 35 cycles or standard-dose paclitaxel. Primary endpoints: OS and PFS (CPS ≥ 1 population). HRs were calculated using stratified Cox proportional hazards models. RESULTS: 366/395 patients (92.7%) with CPS ≥ 1 died. Pembrolizumab demonstrated a trend toward improved OS vs paclitaxel in the CPS ≥ 1 population (HR, 0.81); 24-month OS rates: 19.9% vs 8.5%. Pembrolizumab incrementally increased the OS benefit with PD-L1 enrichment (CPS ≥ 5: HR, 0.72, 24-month rate, 24.2% vs 8.8%; CPS ≥ 10: 0.69, 24-month rate, 32.1% vs 10.9%). There was no difference in median PFS among treatment groups (CPS ≥ 1: HR, 1.25; CPS ≥ 5: 0.98; CPS ≥ 10: 0.79). ORR (pembrolizumab vs paclitaxel) was 16.3% vs 13.6% (CPS ≥ 1), 20.0% vs 14.3% (CPS ≥ 5), and 24.5% vs 9.1% (CPS ≥ 10); median DOR was 19.1 months vs 5.2, 32.7 vs 4.8, and NR vs 6.9, respectively. Fewer treatment-related AEs (TRAEs) occurred with pembrolizumab than paclitaxel (53% vs 84%). CONCLUSION: In this long-term analysis, 2L pembrolizumab did not significantly improve OS but was associated with higher 24-month OS rates than paclitaxel. Pembrolizumab also increased OS benefit with PD-L1 enrichment among patients with PD-L1-positive gastric/GEJ cancer and led to fewer TRAEs than paclitaxel. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02370498.

Characteristics of patients ≥10 years of age with diffuse intrinsic pontine glioma: a report from the International DIPG/DMG Registry.

BACKGROUND: Diffuse intrinsic pontine gliomas (DIPG) generally occur in young school-age children, although can occur in adolescents and young adults. The purpose of this study was to describe clinical, radiological, pathologic, and molecular characteristics in patients ≥10 years of age with DIPG enrolled in the International DIPG Registry (IDIPGR). METHODS: Patients ≥10 years of age at diagnosis enrolled in the IDIPGR with imaging confirmed DIPG diagnosis were included. The primary outcome was overall survival (OS) categorized as long-term survivors (LTS) (≥24 months) or short-term survivors (STS) (<24 months). RESULTS: Among 1010 patients, 208 (21%) were ≥10 years of age at diagnosis; 152 were eligible with a median age of 12 years (range 10-26.8). Median OS was 13 (2-82) months. The 1-, 3-, and 5-year OS was 59.2%, 5.3%, and 3.3%, respectively. The 18/152 (11.8%) LTS were more likely to be older (P < .01) and present with longer symptom duration (P < .01). Biopsy and/or autopsy were performed in 50 (33%) patients; 77%, 61%, 33%, and 6% of patients tested had H3K27M (H3F3A or HIST1H3B), TP53, ATRX, and ACVR1 mutations/genome alterations, respectively. Two of 18 patients with IDH1 testing were IDH1-mutant and 1 was a LTS. The presence or absence of H3 alterations did not affect survival. CONCLUSION: Patients ≥10 years old with DIPG have a median survival of 13 months. LTS present with longer symptom duration and are likely to be older at presentation compared to STS. ATRX mutation rates were higher in this population than the general DIPG population.

Pembrolizumab versus paclitaxel for previously treated advanced gastric or gastroesophageal junction cancer (KEYNOTE-063): A randomized, open-label, phase 3 trial in Asian patients.

BACKGROUND: KEYNOTE-063 (NCT03019588) investigated pembrolizumab versus paclitaxel as second-line therapy in Asian patients with advanced programmed death ligand 1 (PD-L1)-positive (combined positive score ≥1) gastric/gastroesophageal junction (GEJ) cancer. METHODS: This randomized, open-label, phase 3 study was conducted at 36 medical centers in China (mainland), Malaysia, South Korea, and Taiwan. Patients were randomly assigned 1:1 to 200 mg of pembrolizumab intravenously every 3 weeks for ≤2 years or 80 mg/m2 of paclitaxel intravenously every week. Primary end points were overall survival (OS) and progression-free survival (PFS). Secondary end points were objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 and safety. RESULTS: Between February 16, 2017, and March 12, 2018, 94 patients were randomly assigned (47 pembrolizumab/47 paclitaxel) after screening; enrollment was stopped on March 12, 2018, based on the results of the global KEYNOTE-061 study, and patients were followed until the last patient's last visit. Median OS was 8 months (95% confidence interval [CI], 4-10 months) with pembrolizumab versus 8 months (95% CI, 5-11 months) with paclitaxel (hazard ratio [HR], 0.99; 95% CI, 0.63-1.54). Median PFS was 2 months (95% CI, 1-3 months) with pembrolizumab versus 4 months (95% CI, 3-6 months) with paclitaxel (HR, 1.62; 95% CI, 1.04-2.52). ORR was 13% for pembrolizumab versus 19% for paclitaxel. Any-grade treatment-related adverse events occurred in 28 pembrolizumab-treated patients (60%) and 42 paclitaxel-treated patients (96%); grades 3 to 5 events occurred in 5 patients (11%) and 28 patients (64%), respectively. CONCLUSIONS: Definitive conclusions about the efficacy of second-line pembrolizumab in Asian patients with advanced PD-L1-positive gastric/GEJ cancer are limited because of insufficient power, but pembrolizumab was well tolerated in this patient population. Efficacy followed a trend similar to that observed in the phase 3 KEYNOTE-061 trial.

Health-related quality of life in advanced gastric/gastroesophageal junction cancer with second-line pembrolizumab in KEYNOTE-061.

BACKGROUND: In the primary analysis population (i.e., PD-L1 combined positive score [CPS] ≥ 1) of the phase 3 KEYNOTE-061 study (NCT02370498), pembrolizumab did not significantly prolong overall survival or progression-free survival. Pembrolizumab had a favorable safety profile in the all-patient population. We present results of prespecified health-related quality of life (HRQoL) analyses. METHODS: HRQoL was measured using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30), EORTC QLQ gastric cancer questionnaire (QLQ-STO22), and EuroQol 5-dimension, 3-level questionnaire (EQ-5D-3L). Data were analyzed from patients who received ≥ 1 dose of study treatment and who completed ≥ 1 HRQoL assessment. Key analyses included baseline to week 12 least-squares mean (LSM) change in global health status (GHS)/QoL, functional/symptom subscales, and time to deterioration (TTD; ≥ 10-point decrease from baseline) for specific subscales. RESULTS: The HRQoL population included 371 patients (pembrolizumab, n = 188; paclitaxel, n = 183). Compliance and completion rates for all 3 questionnaires were similar in both groups at baseline and week 12. There was no difference in LSM change between groups (- 3.54; 95% CI - 8.92 to 1.84) in GHS/QoL at week 12. LSM change from baseline to week 12 for most QLQ-C30, QLQ-STO22, and EQ-5D-3L subscales indicated some worsening of QoL in both groups. TTD for GHS/QoL, nausea/vomiting, and appetite loss subscales in QLQ-C30 and the pain subscales in QLQ-STO22 were similar between treatment groups. CONCLUSIONS: In this population with advanced gastric and GEJ cancer receiving second-line treatment, HRQoL was similar in patients receiving pembrolizumab and those receiving paclitaxel. CLINICAL TRIAL REGISTRY AND NUMBER: ClinicalTrials.gov, NCT02370498.

Assessment of Pembrolizumab Therapy for the Treatment of Microsatellite Instability-High Gastric or Gastroesophageal Junction Cancer Among Patients in the KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 Clinical Trials.

IMPORTANCE: Immunotherapy has been associated with improved outcomes among patients who have received previous treatment for microsatellite instability-high (MSI-H) tumors. OBJECTIVE: To evaluate the antitumor activity of pembrolizumab therapy vs chemotherapy among patients with MSI-H advanced gastric or gastroesophageal junction (G/GEJ) cancer regardless of the line of therapy in which it was received. DESIGN, SETTING, AND PARTICIPANTS: This post hoc analysis of the phase 2 KEYNOTE-059 (third-line treatment or higher) single-arm trial and the phase 3 KEYNOTE-061 (second-line treatment) and KEYNOTE-062 (first-line treatment) randomized trials included patients with advanced G/GEJ cancer from 52 sites in 16 countries enrolled in KEYNOTE-059, 148 sites in 30 countries enrolled in KEYNOTE-061, and 200 sites in 29 countries enrolled in KEYNOTE-062. Patients were enrolled from March 2, 2015, to March 26, 2016, in KEYNOTE-059; from June 4, 2015, to July 26, 2016, in KEYNOTE-061; and from September 18, 2015, to May 26, 2017, in KEYNOTE-062, with data cutoff dates of August 8, 2018; October 26, 2017; and March 26, 2019; respectively. INTERVENTIONS: Pembrolizumab monotherapy in KEYNOTE-059, pembrolizumab monotherapy or chemotherapy (paclitaxel) in KEYNOTE-061, and pembrolizumab monotherapy, pembrolizumab plus chemotherapy (cisplatin and 5-fluorouracil or capecitabine), or chemotherapy alone in KEYNOTE-062. MAIN OUTCOMES AND MEASURES: Response was assessed centrally using Response Evaluation Criteria in Solid Tumours (RECIST), version 1.1; MSI-H status was determined centrally by polymerase chain reaction testing. RESULTS: At data cutoff, 7 of 174 patients (4.0%) in KEYNOTE-059, 27 of 514 patients (5.3%) in KEYNOTE-061, and 50 of 682 patients (7.3%) in KEYNOTE-062 had MSI-H tumors. Among those with MSI-H tumors, the median overall survival was not reached (NR) for pembrolizumab in KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 or for pembrolizumab plus chemotherapy in KEYNOTE-062. The median progression-free survival (PFS) for pembrolizumab was NR (95% CI, 1.1 months to NR) in KEYNOTE-059 and 17.8 months (95% CI, 2.7 months to NR) in KEYNOTE-061 (vs 3.5 months [95% CI, 2.0-9.8 months] for chemotherapy). In KEYNOTE-062, the median PFS was 11.2 months (95% CI, 1.5 months to NR) for pembrolizumab, NR (95% CI, 3.6 months to NR) for pembrolizumab plus chemotherapy, and 6.6 months (95% CI, 4.4-8.3 months) for chemotherapy. The objective response rate (ORR) for pembrolizumab was 57.1% in KEYNOTE-059 and 46.7% (vs 16.7% for chemotherapy) in KEYNOTE-061. In KEYNOTE-062, the ORR was 57.1% for pembrolizumab , 64.7% for pembrolizumab plus chemotherapy, and 36.8% for chemotherapy. CONCLUSIONS AND RELEVANCE: Findings from this study indicate that MSI-H status may be a biomarker for pembrolizumab therapy among patients with advanced G/GEJ cancer regardless of the line of therapy in which it was received. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT02335411, NCT02370498, and NCT02494583.

KEYNOTE-975 study design: a Phase III study of definitive chemoradiotherapy plus pembrolizumab in patients with esophageal carcinoma.

Despite curative-intent treatment, most patients with locally advanced esophageal cancer will experience disease recurrence or locoregional progression, highlighting the need for new therapies. Current guidelines recommend definitive chemoradiotherapy in patients ineligible for surgical resection, but survival outcomes are poor. Pembrolizumab is well tolerated and provides promising antitumor activity in patients with previously treated, advanced, unresectable esophageal/esophagogastric junction cancer. Combining pembrolizumab with chemoradiotherapy may further improve outcomes in the first-line setting. Here, we describe the design and rationale for the double-blind, Phase III, placebo-controlled, randomized KEYNOTE-975 trial investigating pembrolizumab in combination with definitive chemoradiotherapy as first-line treatment in patients with locally advanced, unresectable esophageal/gastroesophageal junction cancer. Overall survival and event-free survival are the dual primary end points. Clinical trial registration: NCT04210115 (ClinicalTrials.gov).

Efficacy of Pembrolizumab Monotherapy for Advanced Gastric/Gastroesophageal Junction Cancer with Programmed Death Ligand 1 Combined Positive Score ≥10.

PURPOSE: Pembrolizumab demonstrated efficacy in PD-L1-positive [combined positive score (CPS) ≥1] advanced gastric/gastroesophageal junction (G/GEJ) cancer in the first-, second-, and third-line setting in KEYNOTE-062, KEYNOTE-061, and KEYNOTE-059, respectively. To better delineate the specificity of CPS as a predictor of clinical outcomes, we analyzed pembrolizumab efficacy in patients with CPS ≥ 10 in these trials. PATIENTS AND METHODS: Included were patients with CPS ≥ 10 tumors from KEYNOTE-059 cohort 1 (pembrolizumab, n = 46; post hoc), KEYNOTE-061 (pembrolizumab, n = 53; chemotherapy, n = 55; post hoc), and KEYNOTE-062 (pembrolizumab, n = 92; chemotherapy, n = 90; primary). Efficacy outcomes were overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and duration of response (DOR). RESULTS: In KEYNOTE-059, median follow-up was 6 months, median OS was 8 months [95% confidence interval (CI), 5.8-11.1], ORR was 17%, and median (range) DOR was 21 months (3+ to 35+). In KEYNOTE-061, median follow-up was 9 months, median OS (pembrolizumab vs. chemotherapy) was 10 versus 8 months (HR, 0.64; 95% CI, 0.41-1.02), median PFS was 3 months versus 3 months (HR, 0.86; 95% CI, 0.56-1.33), ORR was 25% versus 9%, and median (range) DOR was not reached (4 to 26+ months) versus 7 months (3-7). In KEYNOTE-062, median follow-up was 11 months, median OS (pembrolizumab vs. chemotherapy) was 17 months versus 11 months (HR, 0.69; 95% CI, 0.49-0.97), median PFS was 3 months versus 6 months (HR, 1.09, 95% CI; 0.79-1.49), ORR was 25% versus 38%, and median (range) DOR was 19 months (1+ to 34+) versus 7 months (2+ to 30+). CONCLUSIONS: This comprehensive analysis showed consistent improvements toward more favorable clinical outcomes with pembrolizumab across lines of therapy in patients with CPS ≥ 10 G/GEJ cancer.

Cabozantinib for neurofibromatosis type 1-related plexiform neurofibromas: a phase 2 trial.

Neurofibromatosis type 1 (NF1) plexiform neurofibromas (PNs) are progressive, multicellular neoplasms that cause morbidity and may transform to sarcoma. Treatment of Nf1fl/fl;Postn-Cre mice with cabozantinib, an inhibitor of multiple tyrosine kinases, caused a reduction in PN size and number and differential modulation of kinases in cell lineages that drive PN growth. Based on these findings, the Neurofibromatosis Clinical Trials Consortium conducted a phase II, open-label, nonrandomized Simon two-stage study to assess the safety, efficacy and biologic activity of cabozantinib in patients ≥16 years of age with NF1 and progressive or symptomatic, inoperable PN ( NCT02101736 ). The trial met its primary outcome, defined as ≥25% of patients achieving a partial response (PR, defined as ≥20% reduction in target lesion volume as assessed by magnetic resonance imaging (MRI)) after 12 cycles of therapy. Secondary outcomes included adverse events (AEs), patient-reported outcomes (PROs) assessing pain and quality of life (QOL), pharmacokinetics (PK) and the levels of circulating endothelial cells and cytokines. Eight of 19 evaluable (42%) trial participants achieved a PR. The median change in tumor volume was 15.2% (range, +2.2% to -36.9%), and no patients had disease progression while on treatment. Nine patients required dose reduction or discontinuation of therapy due to AEs; common AEs included gastrointestinal toxicity, hypothyroidism, fatigue and palmar plantar erythrodysesthesia. A total of 11 grade 3 AEs occurred in eight patients. Patients with PR had a significant reduction in tumor pain intensity and pain interference in daily life but no change in global QOL scores. These data indicate that cabozantinib is active in NF1-associated PN, resulting in tumor volume reduction and pain improvement.

First-line pembrolizumab/placebo plus trastuzumab and chemotherapy in HER2-positive advanced gastric cancer: KEYNOTE-811.

Treatment options for patients with HER2-positive advanced gastric cancer are limited, and the prognosis for these patients is poor. Pembrolizumab has demonstrated promising antitumor activity in patients with advanced gastric or gastroesophageal junction adenocarcinoma as monotherapy, in combination with chemotherapy and in combination with trastuzumab. Combining pembrolizumab with trastuzumab and chemotherapy may therefore provide a benefit for patients with advanced HER2-positive gastric cancer. Here we aimed to describe the design of and rationale for the randomized, double-blind, placebo-controlled Phase III KEYNOTE-811 study, which will evaluate the efficacy and safety of pembrolizumab or placebo in combination with trastuzumab and chemotherapy as first-line treatment for patients with advanced HER2-positive gastric or gastroesophageal junction adenocarcinoma. Clinical trial registration: NCT03615326 (ClinicalTrials.gov).

Comparison of multi-shot and single shot echo-planar diffusion tensor techniques for the optic pathway in patients with neurofibromatosis type 1.

PURPOSE: Diffusion tensor imaging (DTI) may be helpful in assessing optic pathway integrity as a marker for treatment in neurofibromatosis type 1 (NF1) patients with optic gliomas (OG). However, susceptibility artifacts are common in typical single-shot echo planar imaging (ssDTI). A readout-segmented multi-shot EPI technique (rsDTI) was utilized to minimize susceptibility distortions of the skull base and improve quantitative metrics. METHODS: Healthy controls, children with NF1 without OG, and NF1 with OG ± visual symptoms were included. All subjects were scanned with both rsDTI and ssDTI sequences sequentially. Diffusion metrics and deterministic fiber tracking were calculated. Tract count, volume, and length were also compared by a two-factor mixed ANOVA. RESULTS: Five healthy controls, 7 NF1 children without OG, and 12 NF1 children with OG were imaged. Six OG patients had visual symptoms. Four subjects had no detectable optic pathway fibers on ssDTI due to susceptibility, for which rsDTI was able to delineate. Tract count (p < 0.001), tract volume (p < 0.001), and FA (P < 0.001) were significantly higher for rsDTI versus ssDTI for all subjects. MD (p < 0.001) and RD (p < 0.001) were significantly lower for rsDTI vs ssDTI. Finally, MD, AD, and RD had a significantly lower difference in NF1 children with visual symptoms compared to NF1 children without visual symptoms only on ssDTI scans. CONCLUSION: DTI with readout-segmented multi-shot EPI technique can better visualize the optic pathway and allow more confident measurements of anisotropy in NF1 patients. This is shown by a significant increase in FA, tract count, and volume with rsDTI versus ssDTI.

Radiation-Induced Cerebral Microbleeds in Pediatric Patients With Brain Tumors Treated With Proton Radiation Therapy.

PURPOSE: Proton beam radiation therapy (PBT) has been increasingly used to treat pediatric brain tumors; however, limited information exists regarding radiation-induced cerebral microbleeds (CMBs) among these patients. The purpose of this study was to evaluate the incidence, risk factors, and imaging appearance of CMBs in pediatric patients with brain tumors treated with PBT. MATERIALS AND METHODS: A retrospective study was performed of 100 pediatric patients with primary brain tumors treated with PBT. CMBs were diagnosed by examination of serial magnetic resonance imaging scans, including susceptibility-weighted imaging. Radiation therapy plans were analyzed to determine doses to individual CMBs. Clinical records were used to determine risk factors associated with the development of CMBs in these patients. RESULTS: The mean age at time of PBT was 8.1 years. The median follow-up duration was 57 months. The median time to development of CMBs was 8 months (mean, 11 months; range, 3-28 months). The percentage of patients with CMBs was 43%, 66%, 80%, 81%, 83%, and 81% at 1 year, 2 years, 3 years, 4 years, 5 years, and >5 years from completion of proton radiation therapy. Most of the CMBs (87%) were found in areas of brain exposed to ≥30 Gy. Risk factors included maximum radiation therapy dose (P = .001), percentage and volume of brain exposed to ≥30 Gy (P = .0004, P = .0005), and patient age at time of PBT (P = .0004). Chemotherapy was not a significant risk factor (P = .35). No CMBs required surgical intervention. CONCLUSIONS: CMBs develop in a high percentage of pediatric patients with brain tumors treated with proton radiation therapy within the first few years after treatment. Significant risk factors for development of CMBs include younger age at time of PBT, higher maximum radiation therapy dose, and higher percentage and volume of brain exposed to ≥30 Gy. These findings demonstrate similarities with CMBs that develop in pediatric patients with brain tumor treated with photon radiation therapy.

Clinical, Radiologic, Pathologic, and Molecular Characteristics of Long-Term Survivors of Diffuse Intrinsic Pontine Glioma (DIPG): A Collaborative Report From the International and European Society for Pediatric Oncology DIPG Registries.

Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials.

Primary Spinal Intradural Extraosseous Ewing Sarcoma in a Pediatric Patient: Case Report and Review of the Literature.

Ewing sarcoma (ES) is an aggressive, primary bone malignancy with occasional soft tissue extension. Purely extra-osseous ES is rare. A primary intraspinal, intradural ES without bone involvement is exceedingly rare. ES may be differentiated from other primitive neuroectodermal tumors by molecular analysis. The authors report the case of a 14-year-old female who suffered an acute neurologic decline from a hemorrhagic, intraspinal, intradural ES. The patient has been tumor free for 2 years after the initial emergency surgery. Our management of the patient and a review of the literature are provided. Considering only those cases with molecular or genetic confirmation of ES, our patient is the fifth pediatric case reported in the English literature.

Radiation-Induced Large Vessel Cerebral Vasculopathy in Pediatric Patients With Brain Tumors Treated With Proton Radiation Therapy.

PURPOSE: The purpose of this research was to evaluate the incidence, time to development, imaging patterns, risk factors, and clinical significance of large vessel cerebral vasculopathy in pediatric patients with brain tumors treated with proton radiation therapy. METHODS AND MATERIALS: A retrospective study was performed on 75 consecutive pediatric patients with primary brain tumors treated with proton radiation therapy. Radiation-induced large vessel cerebral vasculopathy (RLVCV) was defined as intracranial large vessel arterial stenosis or occlusion confirmed on magnetic resonance angiography, computed tomographic angiography, catheter angiography, or a combination of these within an anatomic region with previous exposure to proton beam therapy and not present before radiation therapy. Clinical records were used to determine the incidence, timing, radiation dose to the large vessels, and clinical significance associated with the development of large vessel vasculopathy in these patients. RESULTS: RLVCV was present in 5 of 75 (6.7%) patients and included tumor pathologic features of craniopharyngioma (n=2), ATRT (n=1), medulloblastoma (n=1), and anaplastic astrocytoma (n=1). The median time from completion of radiation therapy to development was 1.5 years (mean, 3.0 years; range, 1.0-7.5 years). Neither mean age at the time of radiation therapy (5.1 years) nor mean radiation therapy dose to the large vessels (54.5 Gy) was a statistically significant risk factor. Four of the 5 patients with RLVCV presented with acute stroke and demonstrated magnetic resonance imaging evidence of acute infarcts in the expected vascular distributions. Angiography studies demonstrated collateral vessel formation in only 2 of the patients with RLVCV. No patients demonstrated acute hemorrhage or aneurysm. Two patients were treated with pial synangiomatosis surgery. CONCLUSIONS: RLVCV can occur in pediatric patients with brain tumors treated with proton radiation therapy. Further studies are necessary to determine potential risk factors for large vessel vasculopathy with proton radiation therapy in comparison with conventional photon radiation therapy.