McWilliams, Robert R.

BACKGROUNDOxaliplatin in combination with either 5‐fluorouracil or capecitabine is commonly used as first‐line therapy for patients with small bowel adenocarcinoma. The addition of irinotecan improves survival in other gastrointestinal tumors but at the cost of hematologic toxicity. The authors performed a phase 2 cooperative group study (North Central Cancer Treatment Group N0543, Alliance) using genotype‐dosed capecitabine, irinotecan, and oxaliplatin (gCAPIRINOX), with dosing assigned based on UDP glucuronosyltransferase family 1 member A1 (UGT1A1) genotype to test: 1) whether the addition of irinotecan would improve outcomes; and 2) whether UGT1A1 genotype‐based dosing could optimize tolerability.METHODSPreviously untreated patients with advanced small bowel adenocarcinoma received irinotecan (day 1), oxaliplatin (day 1), and capecitabine (days 2‐15) in a 21‐day cycle and were dosed with gCAPIRINOX according to UGT1A1*28 genotypes (6/6, 6/7, and 7/7).RESULTSA total of 33 patients (17 with the 6/6 genotype, 10 with the 6/7 genotype, and 6 with the 7/7 genotype) were enrolled from October 2007 to November 2013; 73% were male, with a mean age of 64 years (range, 41‐77 years). Location of the primary tumor included the duodenum (58%), jejunum (30%), and ileum (9%). The regimen yielded a confirmed response rate of 37.5% (95% confidence interval, 21%‐56%), with a median progression‐free survival of 8.9 months and a median overall survival of 13.4 months. Neither hematologic toxicity (grade ≥3 in 52.9%, 30.0%, and 33.3%, respectively, of the 6/6, 6/7, and 7/7 genotype groups) nor tumor response rate (41.2%, 33%, and 33%, respectively) were found to differ significantly by UGT1A1 genotype.CONCLUSIONSUGT1A1 genotype‐directed dosing (gCAPIRINOX) appears to be feasible with favorable rates of hematologic toxicity compared with prior 3‐drug studies in unselected patients. Larger studies would be needed to determine the regimen's comparability to oxaliplatin and capecitabine (CapeOx) alone or if response/toxicity differs among patients with different UGT1A1 genotypes. Cancer 2017;123:3494‐501. © 2017 American Cancer Society.

Purpose Molecular diagnostic testing has become an integral part of the evaluation of patients with metastatic colorectal cancer (CRC). Expanded mutational testing, such as next-generation sequencing (NGS), often identifies mutations with unclear clinical or prognostic implications. One such example is BRAF mutations that occur outside of codon 600 (non-V600 BRAF mutations). Methods We conducted this multicenter, retrospective cohort study to characterize the clinical, pathologic, and survival implications of non-V600 BRAF mutations in metastatic CRC. We pooled patients in whom non-V600 BRAF mutations were identified from NGS databases at three large molecular genetics reference laboratories. Results A total of 9,643 patients with metastatic CRC underwent NGS testing. We identified 208 patients with non-V600 BRAF mutations, which occurred in 2.2% of all patients tested and accounted for 22% of all BRAF mutations identified. Cancers with non-V600 BRAF mutations, compared with cancers with V600E BRAF (V600E BRAF) mutations, were found in patients who were significantly younger (58 v 68 years, respectively), fewer female patients (46% v 65%, respectively), and patients who had fewer high-grade tumors (13% v 64%, respectively) or right-sided primary tumors (36% v 81%, respectively). Median overall survival was significantly longer in patients with non-V600 BRAF-mutant metastatic CRC compared with those with both V600E BRAF-mutant and wild-type BRAF metastatic CRC (60.7 v 11.4 v 43.0 months, respectively; P < .001). In multivariable analysis, non-V600 BRAF mutation was independently associated with improved overall survival (hazard ratio, 0.18; P < .001). Conclusion Non-V600 BRAF mutations occur in approximately 2.2% of patients with metastatic CRC and define a clinically distinct subtype of CRC with an excellent prognosis.

Purpose Treatment options for neuroendocrine tumors (NETs) remain limited. This trial assessed the progression-free survival (PFS) of bevacizumab or interferon alfa-2b (IFN-α-2b) added to octreotide among patients with advanced NETs. Patients and Methods Southwest Oncology Group (SWOG) S0518, a phase III study conducted in a US cooperative group system, enrolled patients with advanced grades 1 and 2 NETs with progressive disease or other poor prognostic features. Patients were randomly assigned to treatment with octreotide LAR 20 mg every 21 days with either bevacizumab 15 mg/kg every 21 days or 5 million units of IFN-α-2b three times per week. The primary end point was centrally assessed PFS. This trial is registered with ClinicalTrials.gov as NCT00569127. Results A total of 427 patients was enrolled, of whom 214 were allocated to bevacizumab and 213 to IFN-α-2b. The median PFS by central review was 16.6 months (95% CI, 12.9 to 19.6 months) in the bevacizumab arm and was 15.4 months (95% CI, 9.6 to 18.6 months) in the IFN arm (hazard ratio [HR], 0.93; 95% CI, 0.73 to 1.18; P = .55). By site review, the median PFS times were 15.4 months (95% CI, 12.6 to 17.2 months) for bevacizumab and 10.6 months (95% CI, 8.5 to 14.4 months) for interferon (HR, 0.90; 95% CI, 0.72 to 1.12; P = .33). Time to treatment failure was longer with bevacizumab than with IFN (HR, 0.72; 95% CI, 0.58 to 0.89; P = .003). Confirmed radiologic response rates were 12% (95% CI, 8% to 18%) for bevacizumab and 4% (95% CI, 2% to 8%) for IFN. Common adverse events with bevacizumab and octreotide included hypertension (32%), proteinuria (9%), and fatigue (7%); with IFN and octreotide, they included fatigue (27%), neutropenia (12%), and nausea (6%). Conclusion No significant differences in PFS were observed between the bevacizumab and IFN arms, which suggests that these agents have similar antitumor activity among patients with advanced NETs.

The optimal surveillance for patients with resected high-risk melanoma is controversial. Select locoregional or oligometastatic recurrences can be cured with salvage resection. Data on the ability of PET/CT to detect such recurrences are sparse. We evaluated whether surveillance PET/CT in patients with resected stage III–IV melanoma led to detection of clinically occult recurrences amenable to curative-intent salvage treatment. We retrospectively identified 1429 melanoma patients who underwent PET/CT between January 2008 and October 2012 at Mayo Clinic (Rochester, Minnesota). A total of 1130 were excluded because of stage I–II, ocular or mucosal melanoma, incomplete resection, PET/CT not performed for surveillance or performed at a different institution, and records not available. A total of 299 patients were eligible. Overall, 162 (52%) patients developed recurrence [locoregional: 77 (48%), distant: 85 (52%)]. The first recurrence was clinically occult in 98 (60%) and clinically evident in 64 (40%). Clinically evident recurrences were more often superficial (skin, subcutaneous, or nodal) or in the brain, whereas clinically occult recurrences more often visceral. Overall, 90% of all recurrences were detected by 2.8 years. In all, 70% of patients with recurrence underwent curative-intent salvage treatment (locoregional: 94%, distant: 48%), with similar rates for clinically occult versus clinically evident recurrences (66 vs. 75%, P=0.240). Overall survival was superior among those who underwent curative-intent salvage treatment [5.9 vs. 1.2 years; hazard ratio=4.27, 95% confidence interval (CI)=2.68–6.80; P<0.001], despite 79% developing recurrence again. PET/CT had high sensitivity (88%, 95% CI=79.94–93.31%), specificity (90%, 95% CI=88.56–91.56%), and negative predictive value (99%, 95% CI=98.46–99.52%). However, the positive predictive value was only 37% (95% CI=31.32–43.68%). In patients with resected stage III–IV melanoma, surveillance PET/CT detected a large proportion of clinically occult recurrences amenable to curative-intent salvage treatment. Despite a high rate of second relapse, curative-intent salvage treatment was associated with superior overall survival. Even though PET/CT had high sensitivity, specificity, and negative predictive value, positive predictive value was poor, highlighting the need for histologic confirmation of PET/CT-detected abnormalities.

463 Background: The genomic assessment of cancer has been revolutionized by next-generation sequencing and is increasingly being applied in the clinic to guide therapeutic decision-making. Time to reporting of results, specimen quantity, and analyte quality have constrained initial clinical applications to gene panels and whole exome based strategies. Methods: Patients underwent surgical resection, excisional or core biopsies, or bone marrow biopsy. Samples were analyzed by whole genome or exome sequencing and RNA sequencing, bioinformatics analysis, and therapeutic target prioritization by a multi-disciplinary Clinical Genomics Board. All prioritized targets were CLIA validated using Sanger sequencing, RT-qPCR, FISH, or IHC as appropriate. Treatment was delivered using off-label FDA approved drugs, clinical trials, or single patient INDs. Results: We have enrolled 40 patients with advanced, treatment-refractory cancers of whom sequencing data is available on 33. The initial 6 patients were evaluated in a non-CLIA pilot phase and 27 in the CLIA enabled phase. Upon availability of the initial report, identified targets of putative therapeutic relevance were then prioritized by the CGB in 22/27 patients (81%) for subsequent CLIA validation. Eleven patients have been treated with genomically selected therapy with partial response in 3/10 assessed patients. A testicular cancer patient had aberrations in two testes specific genes, a copy number gain in TSSK6 and a novel gene fusion between thyroid hormone receptor associated protein 3 (THRAP3) and Tektin 2 (TEKT2). Additionally, a case of papillary renal cell carcinoma had an amplification of YAP1 and a previously unreported P287T mutation in CCND1, suggesting potential benefit with a CDK4/6 inhibitor. Treatment is ongoing and results will be reported. Conclusions: Integrated whole genome analysis in a CLIA setting is feasible. Integration of SNV, copy number and transcriptional data may allow for selection of putative driver genes to enhance targeted therapy decisions. Barriers for future broader implementation include the need for reduced time from biopsy to report and availability of therapies.

245 Background: Gemcitabine (GEM) monotherapy for PDA has modest activity. 17-N-Allylamino-17-demthoxygeldanamycin (Tanespimycin/17AAG), is an HSP90 inhibitor, which results in degradation of a number of client proteins such as RAF and Akt. Arlander et al (J Biol Chem. 2003 278:52572-7) have demonstrated that 17AAG targeting of HSP90 leads to Chk1 degradation. Chk1 is upregulated with GEM treatment which affects cell survival (Karnitz et al. Mol Pharmacol. 2005 68:1636-44). In vitro, the combination demonstrated in vitro synergy. Thus the potential clinical activity in pancreatic cancer of the combination was explored. Methods: A phase II multicenter prospective study was performed using GEM 750 mg/m2 d1,8 and 17AAG 154 mg/m2 d2,9 on a 21 day cycle, as defined in a previous phase I trial. Patients with stage IV PDA, with adequate liver, kidney function and counts, ECOG 0-2 and no prior therapy for metastatic disease were eligible. The primary endpoint of 60% overall survival at 6 months was considered of clinical interest. Sixty-six patients were planned for accrual, and an interim analysis was planned after 25 evaluable patients. Informed, written consent was obtained from all pts. Results: Due to lack of drug availability and failure to achieve the planned endpoint, accrual was halted at 21 pts, enrolled from 5/08 to 9/10, of which 20 were evaluable (1 cancelled prior to treatment). Median age was 61.5 yrs., 55% were male, PS 0 (50%), 1 (45%), 2 (5%); 95% were non-Hispanic white, 1 was African American. Two had received adjuvant therapy for PDA. Tolerability was moderate, with 13 pts (65%) having > grade 3 adverse event (AE), with 15% gr 4 AEs and 0% gr 5. Nausea (20%), vomiting (20%), constipation (15%), dehydration (15%), and anorexia (10%), were the most common non-heme AEs. Lymphopenia (15%), leukopenia (10%) and neutropenia (10%) were common grade 3 hematologic AEs. No complete or partial responses were seen. 40% of patients were alive at 6 months, with a median OS of 5.4 months. Conclusions: HSP 90 inhibitor 17AAG in combination with GEM does not show activity for treatment of PDA. Further trials should not be pursued with this combination. Supported by N01-CM-62205. Clinical trial information: NCT00577889.

288 Background: Programmed-death 1 (PD-1) receptor and its corresponding ligand, PD-L1, have been found to be clinically relevant in maintaining immune tolerance to malignant cells in an increasing number of tumor types. We have previously shown that nearly half of 48 randomly selected, resected small bowel adenocarcinomas at any stage exhibit positive PD-L1 expression. Furthermore, a larger quantity of tumor infiltrating lymphocytes (TILs) within the tumor stroma or microsatellite instability (MSI-H) have been associated with improved likelihood of response to PD-1 and PD-L1 inhibitors. We have descriptively characterized the stromal components of small bowel adenocarcinomas to determine if similar tumor/stromal features to drug-responsive tumors can be seen. Methods: 30 tumors were immunohistochemically stained for CD8 (T-lymphocytes), CD68 (macrophages), and e-cadherin. They were morphologically screened for MSI-H status with light microscopy. PD-L1 staining was previously performed and reported. Results: Of the 30 tumors, there was no correlation between the density of macrophages and T-lymphocytes, nor was there a correlation with the burden of immune cells with e-cadherin expression. 14/30 (47%) tumors had 3+/4+ expression of CD8+ lymphocytes. 7/14 (50%) of these tumors were morphologically MSI-H. No tumors with low CD8+ cells (1+/2+) were MSI-H. PD-L1 expression colocalized exclusively with macrophages and not with lymphocytes. Conclusions: There appears to be no association between the proportions of immune cells and basement membrane integrity. MSI-H tumors are more likely to have a greater quantity of CD8+ lymphocytes in the stroma; however, PD-L1 stromal expression appears to colocalize with macrophages. Further pathologic characterization is needed in patients treated with PD-1 and other immune checkpoint inhibitors to determine the clinical significance of these observations.

446 Background: MutKRAS and mutBRAF are important predictive and prognostic markers, respectively, in colorectal cancer (CRC). However, little is known about why some tumors harbor these mutations. N0147 is a phase III adjuvant trial for stage III CRC patients (N=3397) in which patients completed questionnaires and tumor variables and KRAS/BRAF mutation status was assessed. Methods: 2,323/3,397 patients who were enrolled prior to a 2008 amendment requiring KRAS testing completed a Patient Questionnaire. Primary tumors were assessed for mutKRAS and mutBRAF using standard methods; MMR status was determined using IHC. Multivariate analysis was performed to identify predictors of mutation status. Results: 60% and 86% of mutKRAS and mutBRAF tumors were right-sided, respectively. MutKRAS was less likely if there was a family history of CRC and in ever-smokers, and was nearly mutually exclusive with mutBRAF. MutBRAF was associated with deficient MMR (dMMR), high grade histology, and 4+ positive lymph nodes at surgery. MutBRAF was more likely in patients age > 70, retired persons, ever-smokers, but was less likely in non-whites and men. Conclusions: Smoking, family history of CRC, and dMMR status are associated with lower frequency of mutKRAS , but higher mutBRAF. Both mutations tend to be right sided, and mutBRAF is more common in the elderly, females, and non-Hispanic whites. [Table: see text]

314 Background: Small bowel adenocarcinoma (SB-ACA) is rare, having little prospective data guiding management. A prior phase I study evaluated UGT1A1 genotype specific dosing of oxaliplatin, irinotecan, and capecitabine. Our prospective, multicenter clinical trial assessing tumor response in pts having metastatic SB-ACA, used a similar dosing strategy. Methods: Genotypes were determined via central lab. Previously untreated pts were dosed by UGT1A1*28 genotypes 6/6, 6/7, and 7/7 receiving 100/85/85 mg/m2 oxaliplatin d1, 150/150/75 mg/m2 irinotecan d1, and 1600/400/200 mg/m2 capecitabine (BID) d2-15 of 21 days. The study design was such that 1 confirmed response in 16 pts expanded enrollment to 33 pts, with 7 required for demonstrating efficacy. Results: 28 pts (13-6/6, 10-6/7, 5-7/7) have been enrolled [75% male, mean age 62.5 (range 41-77)]. Location of primary included: duodenum (63%), jejunum (26%), and ileum (7%), with pts having >1 metastatic site (abdominal-41%, bone-7%, liver-56%, lung-30%, nodal-52%, subcutaneous-4%, other-19%). Gr 3+ treatment related toxicity was not significantly different by genotype (50%-6/6, 44%-6/7, 20%-7/7, p=0.48) and included (pts): diarrhea(5), vomiting(5), leukopenia(5), neutropenia(7), and nausea(6). 57% (13 of 23) pts achieved responses during therapy, with a confirmed response rate of 39% (95% CI 0-58%). 18 have died, with a median follow-up of 8.3 mos (range 0-43). Conclusions: UGT1A1 genotype directed dosing with oxaliplatin, irinotecan, and capecitabine appears to result in prolonged response in this population. Larger studies are needed to determine comparability to CapeOx alone or if response/toxicity differs among genotypes. Supported by NIH Grant CA25224, Sanofi-Aventis, and Pfizer. [Table: see text]