RAS Amplification as a Negative Predictor of Benefit from Anti-EGFR-Containing Therapy Regimens in Metastatic Colorectal Cancer.

BACKGROUND: RAS short variant (SV) mutations in colorectal cancer (CRC) are associated with lack of benefit from epidermal growth factor receptor (EGFR) monoclonal antibody (EGFRmAb). However, the clinical implications for RAS amplification (RASa) as a biomarker for anti-EGFR therapy in CRC remain ill defined. METHODS: Genomic analysis was performed using the Foundation Medicine (FM) comprehensive genomic profiling database of 37,233 CRC cases. Clinical outcomes were assessed using two independent cohorts: the City of Hope (COH) cohort of 338 patients with metastatic CRC (mCRC) and the Flatiron Health-FM real-world clinicogenomic database (CGDB) of 3,904 patients with mCRC. RESULTS: RASa was detected in 1.6% (614/37,233) of primarily mCRC. RASa 6-9 (n = 241, 39%), 10-19 (n = 165, 27%), and ≥ 20 (n = 209, 34%) copy number subsets had co-RAS SV/BRAF V600E in 63%/3%, 31%/0.6%, and 4.8%/0% of cases, respectively. In the COH cohort, six patients with RASa (13-54 copies) received EGFRmAb, four of six had progressive disease, two had stable disease, and median time to treatment discontinuation (TTD) was 2.5 months. Of the CGDB EGFRmAb-treated patients, those with RASa (n = 9) had median TTD of 4.7 months and overall survival (OS) of 11.4 months, those with RAS SV (n = 101) had median TTD and OS of 5.3 and 9.4 months, and those with RAS/BRAF wild-type (n = 608) had median TTD and OS of 7.6 and 13.7 months. CONCLUSION: Patients with RASa without RAS mutations (1.1% of mCRC) may have poor outcomes on EGFRmAb, although numbers herein were small, and interpretation is confounded by combination chemotherapy. Larger independent studies are warranted to determine if RASa, including degree of amplification, may act similarly to RAS mutation as a resistance mechanism to EGFRmAb therapies. IMPLICATIONS FOR PRACTICE: Genomic data suggest that RAS amplification occurs as the sole RAS/RAF alteration in >1% of colorectal cancer cases and that degree of amplification inversely correlates with co-occurring MAPK pathway alterations. Preliminary clinical evidence suggests that RAS amplification may function similarly to RAS mutation as a negative predictor of benefit from anti-epidermal growth factor receptor therapies in colorectal cancer. More clinical data are needed, and comprehensive genomic profiling, including detection of RAS amplification, should be used in trial design to inform therapy selection.

Increased long-term survival among patients with hepatocellular carcinoma after implementation of Model for End-stage Liver Disease score.

BACKGROUND & AIMS: Assignment of Model for End-stage Liver Disease (MELD) exception points to patients with hepatocellular carcinoma (HCC) who fall within Milan criteria, which began in 2003, increases their priority on liver transplantation waitlists. However, little is known about how this change affected survival of all patients with HCC (transplant eligible and ineligible). We compared long-term survival of HCC patients before and after this change. METHODS: We performed a large population-based cohort study by using the Surveillance, Epidemiology, and End Results cancer registry to investigate survival times of patients with HCC before those who met the Milan criteria were given MELD exception points (1998-2003) and afterward (2004-2010) by using Kaplan-Meier methods. Multivariate Cox proportional hazards models evaluated independent predictors of survival. RESULTS: During 2004-2010, a significantly higher percentage of patients with HCC survived for 5 years compared with 1998-2003 (21.9% vs 13.0%, P < .001). This difference remained significant among all treatment groups (no therapy: 15.2% vs 10.2%, P < .001; local tumor destruction: 37.6% vs 22.1%, P < .001; resection: 55.5% vs 39.2%, P < .001; transplantation: 77.2% vs 73.1%, P = .12). Multivariate Cox proportional hazards models, inclusive of sex, age, ethnicity, Milan criteria, number and stage of tumor, and time period, showed increased survival of patients during 2004-2010 (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.83-0.91; P < .001). Compared with non-Hispanic whites, Asians (HR, 0.81; 95% CI, 0.77-0.86; P < .001) and Hispanics (HR, 0.89; 95% CI, 0.84-0.95; P < .001) had longer survival times, whereas blacks had a trend toward shorter survival times (HR, 1.05; 95% CI, 0.98-1.13; P = .16). CONCLUSIONS: Patients with HCC who met Milan criteria had significantly longer survival times after implementation of the MELD exception points, regardless of sex or ethnicity. Blacks continued to have the lowest rates of 5-year survival.

Limitations of body surface area-based activity calculation for radioembolization of hepatic metastases in colorectal cancer.

PURPOSE: To calculate absorbed radiation doses in patients treated with resin microspheres prescribed by the body surface area (BSA) method and to analyze dose-response and toxicity relationships. MATERIALS AND METHODS: A retrospective review was performed of 45 patients with colorectal carcinoma metastases who received single-session whole-liver resin microsphere radioembolization. Prescribed treatment activity was calculated using the BSA method. Liver volumes and whole-liver absorbed doses (D(WL)) were calculated. D(WL) was correlated with toxicity and radiographic and biochemical response. RESULTS: The standard BSA-based administered activity (range, 0.85-2.58 GBq) did not correlate with D(WL) (mean, 50.4 Gy; range, 29.8-74.7 Gy; r = -0.037; P = .809) because liver weight was highly variable (mean, 1.89 kg; range, 0.94-3.42 kg) and strongly correlated with D(WL) (r = -0.724; P < .001) but was not accounted for in the BSA method. Patients with larger livers were relatively underdosed, and patients with smaller livers were relatively overdosed. Patients who received D(WL) > 50 Gy experienced more toxicity and adverse events (> grade 2 liver toxicity, 46% vs 17%; P < .05) but also responded better to the treatment than patients who received D(WL)< 50 Gy (disease control, 88% vs 24%; P < .01). CONCLUSIONS: Using the standard BSA formula, the administered activity did not correlate with D(WL). Based on this short-term follow-up after salvage therapy in patients with late stage metastatic colorectal carcinoma, dose-response and dose-toxicity relationships support using a protocol based on liver volume rather than BSA to prescribe the administered activity.

Understanding Racial and Ethnic Inequities in Uptake and Outcomes Following Multigene Prognostic Testing in Early Breast Cancer: The Promise of Real-World Data.

In the past decades, multigene prognostic testing, such as Oncotype DX (ODX), has been increasingly used to inform treatment decisions for patients with early-stage breast cancer. This advance in precision oncology has increased existing concerns about differential access to genomic testing across racial and ethnic groups. The investigation by Moore and colleagues, analyzing real-world data from the National Cancer Database, shows that patients of color with breast cancer were less likely to receive ODX testing and Black patients were more likely to have a high risk Recurrence Score (RS) compared with White patients. This study emphasizes that the appropriate adoption of ODX testing is critical to promote equitable cancer care for patients with breast cancer. The reported associations on overall survival across specific racial and ethnic groups provided here give additional insight to the known associations between the ODX RS and outcomes of distant recurrence and cancer-specific mortality. Analyses of contemporary, real-world data from diverse populations with long-term follow-up should continue to keep pace with the expansion of precision breast cancer care to better understand and mitigate potentially widening inequities in genomic testing. See related article by Moore et al., p. 821.

ERBB2 Copy Number as a Quantitative Biomarker for Real-World Outcomes to Anti-Human Epidermal Growth Factor Receptor 2 Therapy in Advanced Gastroesophageal Adenocarcinoma.

PURPOSE: Human epidermal growth factor receptor 2 (HER2) overexpression or amplification (ERBB2amp) are biomarkers for approved anti-HER2 therapies. ERBB2amp may better predict response compared with immunohistochemistry or in situ hybridization, and quantitative copy number (CN) may further stratify patients. We characterized ERBB2amp in advanced gastroesophageal adenocarcinomas (GEA) and hypothesized that increased CN was associated with better outcome to trastuzumab. METHODS: Comprehensive genomic profiling, including assessment of ERBB2amp, was performed for 12,905 GEA tissue cases. Clinical outcomes were assessed using a clinicogenomic database linking deidentified electronic health record-derived clinical data to genomic data. Multivariable Cox proportional hazard models were used for real-world progression-free survival (rwPFS) comparisons. RESULTS: ERBB2amp (CN ≥ 5) was detected in 15% (1,934 of 12,905) of GEA; median CN 22 (interquartile range 9-73). Median ERBB2 amplicon size was 0.27 megabase (interquartile range 0.13-0.95), and smaller amplicons were associated with higher CN (P < .001). In the clinicogenomic database, of 101 evaluable first-line trastuzumab-treated patients, ERBB2 CN was a significant predictor of rwPFS as a continuous variable (adjusted hazard ratio = 0.73; 95% CI, 0.60 to 0.89; P = .002), whereas ERBB2 CN was not predictive of rwPFS on chemotherapy (adjusted hazard ratio = 0.93; 95% CI, 0.73 to 1.20; P = .59). Among trastuzumab-treated patients, no significant associations with ERBB2 CN were observed for disease site, age, stage at advanced diagnosis, or most selected coalterations. CONCLUSION: ERBB2amp was detected in 15% of GEA tissue samples, with significant diversity in ERBB2 CN and amplicon focality. ERBB2 CN was predictive of rwPFS as a continuous variable for patients treated with trastuzumab. Further studies exploring the clinical utility of quantitative ERBB2 CN, particularly in the setting of the evolving anti-HER2 landscape and combination therapies, are warranted.

The Development Of RRx-001, A Novel Nitric-Oxide-Mediated Epigenetically Active Anticancer Agent.

BACKGROUND: RRx-001 is a novel NO and hypoxia mediated anticancer agent with epigenetic activity. In the first-in-human, Phase I trial, 5/5 patients who progressed on RRx-001 treatment were resensitized to previously refractory therapy, hinting at a generalized resensitization effect. AIMS: A randomized open-label multi-part, multi-center phase II trial of RRx-001 versus regorafenib (ROCKET) has commenced to explore the resensitization and/or 'episensitization' potential in irinotecan refractory tumors and its impact on overall survival. METHODS: Patients with irinotecan-refractory metastatic colorectal cancer with an ECOG PS 0-1 who progressed on oxaliplatin-, and irinotecan-based regimens with or without bevacizumab, cetuximab or panitumumab are randomized 2:1 to receive RRx-001 16.5mg/m2 IV 1x/week or regorafenib 160mg orally 21 of 28 days until progression or unacceptable toxicity followed by treatment with refractory irinotecan-based therapies. RESULTS: To date, 26 patients have been randomized with 18 patients evaluable for resensitization. Post RRx-001 patients demonstrated marked decreases in CEA in 12/13 patients as compared to 5 patients receiving regorafenib who were too systemically unwell to proceed to subsequent treatment. Progression free survival (ongoing) for RRx-001+irinotecan is 4.9 months compared 1.8 months on Regorafenib+irinotecan. CONCLUSION: Early results in the ROCKET study suggest that RRx-001-mediated resensitization to previously refractory therapies may have a generalized effect, independent of KRAS or p53 status. These early results are intriguing, suggesting improved QOL and overall survival over currently approved therapy in the chemotherapy refractory colorectal cancer.