Multicenter double-blind randomized phase II: FOLFOX + ziv-aflibercept/placebo for patients (pts) with chemo-naive metastatic esophagogastric adenocarcinoma (MEGA)

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Background: FOLFOX has RR 53% and PFS 6.8 months in MEGA (CALGB 80403). VEGF inhibition has improved survival in some but not all randomized trials in MEGA. Ziv-aflibercept binds VEGF-A, B and PlGF and has improved survival in refractory metastatic colorectal cancer. Methods: All pts received mFOLFOX6 q14d. Pts were randomized 2:1 to A) ziv-aflibercept 4mg/kg/d1 or B) placebo. Pts were restaged every 8wks. Primary endpoint: 6mos PFS. Results: 64 pts enrolled (Jan 2013-Apr 2015): sex: 55M/9F; age (median): 32-83 (62); ECOG PS 0/1/2: 33/28/3; primary tumor: esophagus 26/GEJ 18/gastric 20; measurable/evaluable: 52/12; metastases: LN 48/liver 25/lung 15, other 12/adrenal 4/bone 3. Of 64 pts: 34 POD, 9 off for tox, 4 died on tx, 3 withdrew, 4 other, 10 on tx (see Table). Conclusion: Ziv-aflibercept did not significantly improve the efficacy of FOLFOX. HTN was predictive of response to ziv-aflibercept. Except for HTN, there was no significant difference in toxicity between tx arms. Clinical trial information: NCT01747551. [Table: see text]

Identification of a Variety of Mutations in Cancer Predisposition Genes in Patients With Suspected Lynch Syndrome

BACKGROUND & AIMS

Multigene panels are commercially available tools for hereditary cancer risk assessment that allow for next-generation sequencing of numerous genes in parallel. However, it is not clear if these panels offer advantages over traditional genetic testing. We investigated the number of cancer predisposition gene mutations identified by parallel sequencing in individuals with suspected Lynch syndrome.

METHODS

We performed germline analysis with a 25-gene, next-generation sequencing panel using DNA from 1260 individuals who underwent clinical genetic testing for Lynch syndrome from 2012 through 2013. All patients had a history of Lynch syndrome-associated cancer and/or polyps. We classified all identified germline alterations for pathogenicity and calculated the frequencies of pathogenic mutations and variants of uncertain clinical significance (VUS). We also analyzed data on patients' personal and family history of cancer, including fulfillment of clinical guidelines for genetic testing.

RESULTS

Of the 1260 patients, 1112 met National Comprehensive Cancer Network (NCCN) criteria for Lynch syndrome testing (88%; 95% confidence interval [CI], 86%-90%). Multigene panel testing identified 114 probands with Lynch syndrome mutations (9.0%; 95% CI, 7.6%-10.8%) and 71 with mutations in other cancer predisposition genes (5.6%; 95% CI, 4.4%-7.1%). Fifteen individuals had mutations in BRCA1 or BRCA2; 93% of these met the NCCN criteria for Lynch syndrome testing and 33% met NCCN criteria for BRCA1 and BRCA2 analysis (P = .0017). An additional 9 individuals carried mutations in other genes linked to high lifetime risks of cancer (5 had mutations in APC, 3 had bi-allelic mutations in MUTYH, and 1 had a mutation in STK11); all of these patients met NCCN criteria for Lynch syndrome testing. A total of 479 individuals had 1 or more VUS (38%; 95% CI, 35%-41%).

CONCLUSIONS

In individuals with suspected Lynch syndrome, multigene panel testing identified high-penetrance mutations in cancer predisposition genes, many of which were unexpected based on patients' histories. Parallel sequencing also detected a high number of potentially uninformative germline findings, including VUS.

A phase II trial of cabozantinib (XL-184) in patients with advanced cholangiocarcinoma

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Background: Cholangiocarcinoma (CCA) carries a poor prognosis in advanced stages, and no standard treatment exists beyond the first line gemcitabine/platinum based combination regimen. Based on preclinical evidence of dysregulation of the VEGF and c-MET pathways in CCA, we performed a single arm phase II study of the dual VEGF receptor and c-MET small molecule inhibitor cabozantinib in patients with advanced CCA. Methods: All eligible pts had histologically confirmed unresectable or metastatic CCA and had progressed after 1 or 2 lines of systemic therapy. Pts were treated with cabozantinib 60mg orally daily continuously for 28 day cycles. Tumor assessments were obtained radiologically every 8 weeks. The primary endpoint was progression free survival (PFS). A Simon two stage design was used, and 9 of 20 pts had to be progression free at 16 weeks in order to proceed to the second stage. Results: Nineteen pts (male 32%; median age 67 years old; intrahepatic vs extrahepatic CCA, 95 vs 5%; 1 vs 2 previous lines of systemic therapy, 53% vs 47%%) were enrolled and all received at least one dose of study drug. After 12 pts failed to be progression free at 16 weeks, the study was terminated as it was determined that the criterion for proceeding to stage 2 could not be met. The median follow-up was 4.07 months (mos). No objective responses were seen. The median PFS was 1.77 mos (95% CI, 1.63-5.37), and the median overall survival was 5.20 mos (95% CI, 2.70-8.17). Eleven (58%) patients required dose reductions. Grade 3 and 4 adverse events occurred in 79% of pts and included neutropenia, epistaxis, hyperbilirubinemia, alkaline phosphatemia, AST/ALT elevation, anemia, lipasemia, and hypertension. One pt had a bowel perforation and another developed an enterocutaneous fistula while on the study drug. VEGF and c-MET pathway-related biomarker analysis is ongoing. Conclusions: Cabozantinib demonstrated limited antitumor activity in an unselected population of pts with advanced CCA. Despite close monitoring, a high rate of > grade 3 toxicities was observed at 60 mg daily dosing. This pt population may be more sensitive to drug doses tolerated by other solid tumor patient populations, and therefore, close monitoring remains critical for these pts in early phase clinical trials. Clinical trial information: NCT01954745.

Therapy-associated polyposis as a late sequela of cancer treatment

Survivors of childhood cancers are at increased risk of developing secondary gastrointestinal cancers, including colorectal cancer, later in life, possibly from exposure to abdominopelvic radiotherapy and/or alkylating chemotherapy. Profuse gastrointestinal polyposis is associated with rare, inherited colorectal cancer predisposition syndromes, most commonly caused by mutations in the adenomatous polyposis coli (APC) or mutY homolog (MUTYH) genes. We describe 5 patients who developed gastrointestinal polyposis many years after radiotherapy and chemotherapy for a childhood cancer. Genetic analysis of all 5 subjects did not identify pathogenic germline mutations in APC or MUTYH. Chemotherapy and/or radiotherapy therefore might cause gastrointestinal polyposis in some patients by undiscovered mechanisms.

Impact of genetic testing on endometrial cancer risk-reducing practices in women at risk for Lynch syndrome

OBJECTIVE

Due to the increased lifetime risk of endometrial cancer (EC), guidelines recommend that women with Lynch syndrome (LS) age ≥ 35 undergo annual EC surveillance or prophylactic hysterectomy (PH). The aim of this study was to examine the uptake of these risk-reducing strategies.

METHODS

The study population included women meeting clinical criteria for genetic evaluation for LS. Data on cancer risk-reducing behaviors were collected from subjects enrolled in two distinct studies: (1) a multicenter cross-sectional study involving completion of a one-time questionnaire, or (2) a single-center longitudinal study in which subjects completed questionnaires before and after undergoing genetic testing. The main outcome was uptake of EC risk-reducing practices.

RESULTS

In the cross-sectional cohort, 58/77 (75%) women at risk for LS-associated EC reported engaging in EC risk-reduction. Personal history of genetic testing was associated with uptake of EC surveillance or PH (OR 17.1; 95% CI 4.1-70.9). Prior to genetic testing for LS, 26/40 (65%) women in the longitudinal cohort reported engaging in EC risk-reduction. At one-year follow-up, 16/16 (100%) mismatch repair (MMR) gene mutation carriers were adherent to guidelines for EC risk-reduction, 9 (56%) of whom had undergone PH. By three-year follow-up, 11/16 (69%) MMR mutation carriers had undergone PH. Among women with negative or uninformative genetic test results, none underwent PH after testing.

CONCLUSIONS

Genetic testing for LS is strongly associated with uptake of EC risk-reducing practices. Women found to have LS in this study underwent prophylactic gynecologic surgery at rates comparable to those published for BRCA1/2 mutation carriers.

Microsatellite instability and DNA mismatch repair protein deficiency in Lynch syndrome colorectal polyps

Colorectal cancers associated with Lynch syndrome are characterized by deficient DNA mismatch repair (MMR) function. Our aim was to evaluate the prevalence of microsatellite instability (MSI) and loss of MMR protein expression in Lynch syndrome-associated polyps. Sixty-two colorectal polyps--37 adenomatous polyps, 23 hyperplastic polyps, and 2 sessile serrated polyps (SSP)--from 34 subjects with germline MMR gene mutations were tested for MSI using a single pentaplex PCR for five mononucleotide repeat microsatellite markers, and also for expression of MLH1, MSH2, MSH6, and PMS2 proteins by immunohistochemistry. High-level MSI (MSI-H) was seen in 15 of 37 (41%) adenomatous polyps, one of 23 (4%) hyperplastic polyps, and one of two (50%) SSPs. Loss of MMR protein expression was seen in 18 of 36 (50%) adenomatous polyps, zero of 21 hyperplastic polyps, and zero of two SSPs. Adenomatous polyps 8 mm or larger in size were significantly more likely to show MSI-H [OR, 9.98; 95% confidence interval (CI), 1.52-65.65; P = 0.02] and deficient MMR protein expression (OR, 3.17; 95% CI, 1.20-8.37; P = 0.02) compared with those less than 8 mm in size. All (six of six) adenomatous polyps 10 mm or larger in size showed both MSI-H and loss of MMR protein expression by immunohistochemistry. Our finding that the prevalence of MMR deficiency increases with the size of adenomatous polyps suggests that loss of MMR function is a late event in Lynch syndrome-associated colorectal neoplasia. Although testing large adenomatous polyps may be of value in the diagnostic evaluation of patients with suspected Lynch syndrome, the absence of an MMR-deficient phenotype in an adenoma cannot be considered as a strong evidence against Lynch syndrome, as it is with colorectal carcinomas.

Recruitment of osteoclast precursors by stromal cell derived factor-1 (SDF-1) in giant cell tumor of bone

Giant cell tumor (GCT) of bone is a unique bone lesion that is characterized by an excessive number of multinucleated osteoclasts. GCT consists of neoplastic stromal cells, multinucleated osteoclasts and their precursors, thus serving as a naturally occurring human disease model for the study of osteoclastogenesis. It still remains unclear how stromal cells of GCT recruit osteoclast precursors. In the present study, we characterized the cellular components of GCT and confirmed the presence of CD14(+)-monocytes/CD68(+)-macrophages and CD34(+)-hematopoetic stem cells that express CXCR4, a specific receptor for SDF-1; SDF-1 gene expression and presence of SDF-1 protein were confirmed by real time RT-PCR, in situ hybridization, and immunohistochemistry in the GCT tissue and cultured cells. SDF-1 was present at 25-50 ng/ml in the conditioned media from the GCT cultures, which is in the range of physiological chemotactic concentration. Migration of osteoclast precursors was 2.5-fold higher in response to GCT conditioned media compared to the control media; and migration was inhibited by an average of 36% with anti-SDF-1 neutralizing antibody or competing recombinant SDF-1. These results suggest that SDF-1 is one of the significant chemoattractant factors involved in the recruitment of hematopoietic osteoclast precursor cells during tumor-induced osteoclastogenesis.