Phase 1 study of olaratumab plus doxorubicin in Japanese patients with advanced soft-tissue sarcoma.

Olaratumab, a monoclonal antibody targeting human platelet-derived growth factor receptor α, plus doxorubicin significantly improved overall survival in patients with advanced soft-tissue sarcoma (STS) in a prior phase 1b/2 randomized trial. Subsequent exposure-response analysis suggested that higher olaratumab exposures earlier might improve outcomes in patients at risk of early disease progression. This phase 1 study (3 treatment cohorts; minimum 6 patients each) investigated the safety, pharmacokinetics and antitumor activity of olaratumab plus doxorubicin in Japanese patients with STS. Patients received olaratumab 15 mg/kg on Days 1 and 8 during each 21-day cycle until disease progression. Patients in Cohort 3 received a 20 mg/kg loading dose of olaratumab in Cycle 1. Doxorubicin was administered for up to 6 cycles. Patients in Cohort 1 received doxorubicin 25 mg/m2 on Days 1, 2 and 3. Patients in Cohorts 2 and 3 received doxorubicin 75 mg/m2 on Day 1. One patient in Cohort 2 experienced a dose-limiting toxicity of Grade 3 febrile neutropenia. Most treatment-emergent adverse events were of mild and moderate severity, and were known doxorubicin toxicities. Olaratumab serum concentrations in Cohort 3 reached a steady-state exceeding the target level in Cycle 1. Partial response was confirmed in 4 patients (2 each in Cohorts 2 and 3). Olaratumab plus doxorubicin had an acceptable safety profile in patients with STS. A loading dose of olaratumab 20 mg/kg was effective for achieving minimum serum concentrations above the target trough level in Cycle 1.

Randomized Phase 2 Clinical Trial of Olaratumab in Combination with Gemcitabine and Docetaxel in Advanced Soft Tissue Sarcomas.

Gemcitabine plus docetaxel is an effective treatment regimen for advanced soft tissue sarcomas (STSs). However, the prognosis for patients remains poor, and thus there is an urgent medical need for novel and effective therapies to improve long-term outcomes. The aim of the ANNOUNCE 2 trial was to explore the addition of olaratumab (O) to gemcitabine (G) and docetaxel (D) for advanced STS. Adults with unresectable locally advanced/metastatic STS, ≤2 prior lines of systemic therapy, and ECOG PS 0-1 were eligible. In Phase 2, patients were randomized 1:1 from two cohorts (O-naïve and O-pretreated) to 21-day cycles of olaratumab (20 mg/kg Cycle 1 and 15 mg/kg other cycles, Days 1 and 8), gemcitabine (900 mg/m2, Days 1 and 8), and docetaxel (75 mg/m2, Day 8). The primary objective was overall survival (OS) in the O-naïve population (α level = 0.20). Secondary endpoints included OS (O-pretreated), other efficacy parameters, patient-reported outcomes, safety, pharmacokinetics, and immunogenicity. A total of 167 and 89 patients were enrolled in the O-naïve and O-pretreated cohorts, respectively. Baseline patient characteristics were well balanced. No statistically significant difference in OS was observed between the investigational vs. control arm for either cohort (O-naïve cohort: HR = 0.95 (95% CI: 0.64-1.40), p = 0.78, median OS, 16.8 vs. 18.0 months; O-pretreated cohort: HR = 0.67 (95% CI: 0.39-1.16), p = 0.15, median OS 19.8 vs. 17.3 months). Safety was manageable across treatment arms. There was no statistically significant difference in the primary endpoint of OS between the two arms in the O-naïve population, and therefore based on hierarchical evaluation no other outcomes in this study can be considered statistically significant. No new safety signals were observed.

Analytical Accuracy of RET Fusion Detection by Break-Apart Fluorescence In Situ Hybridization.

CONTEXT.­: RET gene fusions are oncogenic drivers in nonsmall cell lung cancer and nonmedullary thyroid cancer. Selpercatinib (RETEVMO), a targeted inhibitor of RET, was approved by the US Food and Drug Administration for the treatment of RET fusion-positive nonsmall cell lung cancer and nonmedullary thyroid cancer emphasizing the need for rapid and accurate diagnosis of RET fusions. Fluorescence in situ hybridization (FISH) has been used to detect gene rearrangements, but its performance detecting RET rearrangements is understudied. OBJECTIVE.­: To validate and describe the performance of Abbott Molecular RET break-apart FISH probes for detecting RET rearrangements. DESIGN.­: A training set with RET fusion-positive (13) and RET fusion-negative nonsmall cell lung cancer and nonmedullary thyroid cancer samples (12) was used to establish criteria for FISH scoring. The scoring criteria was then applied to a larger validation set of samples (96). RESULTS.­: A cutoff of 19% or more positive nuclei by FISH was established in the training set and determined by the mean ±3 SD. The validation set was tested using Abbott Molecular RET break-apart FISH compared with sequencing. With this cutoff, a sensitivity of 86% (12 of 14) and specificity of 99% (81 of 82) was achieved. Bootstrapping showed sensitivity could be optimized by using a greater than 13% cutoff with indeterminate samples of 13% to 18% abnormal nuclei requiring confirmation by an orthogonal method. Using this 3-tier scoring system sensitivity increased to 100% (14 of 14) and specificity was 96% (79 of 82). CONCLUSIONS.­: Abbott Molecular break-apart FISH probes can be used to detect RET fusions. Laboratories can optimize cutoffs and/or testing algorithms to maximize sensitivity and specificity to ensure appropriate patients receive effective, timely therapy.

Circulating Tumor Cells and Biomarker Modulation with Olaratumab Monotherapy Followed by Olaratumab plus Doxorubicin: Phase Ib Study in Patients with Soft-Tissue Sarcoma.

This phase Ib study enumerated whole blood circulating tumor cells (CTC) and evaluated biomarkers in patients with potentially resectable soft-tissue sarcoma (STS) treated with olaratumab monotherapy (20 mg/kg) for one cycle followed by up to six cycles of olaratumab (20 mg/kg, cycles 1-2; 15 mg/kg, cycles 3-7) plus doxorubicin (75 mg/m2 on day 1). CTCs, platelet-derived growth factor receptors (PDGFR), and PDGF ligand expression in tumor tissue pre- and post-olaratumab monotherapy were evaluated. Antitumor activity, safety, pharmacokinetics, and PET/biomarker association with clinical outcome were assessed. Of 51 treated patients, 35, 43, and 37 were evaluable for CTC enumeration, PDGFRs, and PDGF ligand expression, respectively. An increase in CTCs at cycle 1 day 8 was observed, followed by a significant reduction by cycle 3 day 1 or 30-day follow-up. Decrease in CTC counts after olaratumab monotherapy was higher in patients with disease control than without disease control (57.9% vs. 31.2%). Baseline IHC expression was positive in most patients for PDGFRα [n = 31 (72.1%)] and PDGFRß [n = 36 (83.7%)]. Similar rates were observed post-olaratumab monotherapy [PDGFRα, n = 30 (69.8%); PDGFRß, n = 33 (76.7%)]. Eleven patients (29.7%) showed a 30% reduction by RT-PCR in PDGFRα at cycle 2. PDGFR expression and PET response showed no correlation with clinical outcome. Safety and pharmacokinetic profiles were consistent with previous reports. This study, the first to use a validated method for CTC detection, confirms that CTC enumeration in STS is feasible. However, no correlation was observed between PDGFRα expression and clinical outcome.

The Genomic Landscape of Intrinsic and Acquired Resistance to Cyclin-Dependent Kinase 4/6 Inhibitors in Patients with Hormone Receptor-Positive Metastatic Breast Cancer.

Mechanisms driving resistance to cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in hormone receptor-positive (HR+) breast cancer have not been clearly defined. Whole-exome sequencing of 59 tumors with CDK4/6i exposure revealed multiple candidate resistance mechanisms including RB1 loss, activating alterations in AKT1, RAS, AURKA, CCNE2, ERBB2, and FGFR2, and loss of estrogen receptor expression. In vitro experiments confirmed that these alterations conferred CDK4/6i resistance. Cancer cells cultured to resistance with CDK4/6i also acquired RB1, KRAS, AURKA, or CCNE2 alterations, which conferred sensitivity to AURKA, ERK, or CHEK1 inhibition. Three of these activating alterations-in AKT1, RAS, and AURKA-have not, to our knowledge, been previously demonstrated as mechanisms of resistance to CDK4/6i in breast cancer preclinically or in patient samples. Together, these eight mechanisms were present in 66% of resistant tumors profiled and may define therapeutic opportunities in patients. SIGNIFICANCE: We identified eight distinct mechanisms of resistance to CDK4/6i present in 66% of resistant tumors profiled. Most of these have a therapeutic strategy to overcome or prevent resistance in these tumors. Taken together, these findings have critical implications related to the potential utility of precision-based approaches to overcome resistance in many patients with HR+ metastatic breast cancer.This article is highlighted in the In This Issue feature, p. 1079.

Brachyury, SOX-9, and podoplanin, new markers in the skull base chordoma vs chondrosarcoma differential: a tissue microarray-based comparative analysis.

The distinction between chondrosarcoma and chordoma of the skull base/head and neck is prognostically important; however, both have sufficient morphologic overlap to make delineation difficult. As a result of gene expression studies, additional candidate markers have been proposed to help in separating those entities. We sought to evaluate the performance of new markers: brachyury, SOX-9, and podoplanin alongside the more traditional markers glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen. Paraffin blocks from 103 skull base/head and neck chondroid tumors from 70 patients were retrieved (1969-2007). Diagnoses were made based on morphology and/or whole-section immunohistochemistry for cytokeratin and S100 protein yielding 79 chordomas (comprising 45 chondroid chordomas and 34 conventional chordomas), and 24 chondrosarcomas. A tissue microarray containing 0.6 mm cores of each tumor in triplicate was constructed using a manual array (MTA-1; Beecher Instruments). For visualization of staining, the ImmPRESS detection system (Vector Laboratories) with 2-diaminobenzidine substrate was used. Sensitivities and specificities were calculated for each marker. Core loss from the microarray ranged from 25 to 29% yielding 66-78 viable cases per stain. The classic marker, cytokeratin, still has the best performance characteristics. When combined with brachyury, accuracy improves slightly (sensitivity and specificity for detection of chordoma 98 and 100%, respectively). Positivity for both epithelial membrane antigen and AE1/AE3 had a sensitivity of 90% and a specificity of 100% for detecting chordoma in this study. SOX-9 is apparently common to both notochordal and cartilaginous differentiation, and is not useful in the chordoma-chondrosarcoma differential diagnosis. Glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen did not outperform other markers, and are less useful in the diagnosis of chordoma vs chondrosarcoma. Podoplanin still remains the only positive marker for chondrosarcoma, though its accuracy is less than previously reported.

Olaratumab Exerts Antitumor Activity in Preclinical Models of Pediatric Bone and Soft Tissue Tumors through Inhibition of Platelet-Derived Growth Factor Receptor α.

Purpose: Platelet-derived growth factor receptor α (PDGFRα) is implicated in several adult and pediatric malignancies, where activated signaling in tumor cells and/or cells within the microenvironment drive tumorigenesis and disease progression. Olaratumab (LY3012207/IMC-3G3) is a human mAb that exclusively binds to PDGFRα and recently received accelerated FDA approval and conditional EMA approval for treatment of advanced adult sarcoma patients in combination with doxorubicin. In this study, we investigated olaratumab in preclinical models of pediatric bone and soft tissue tumors.Experimental Design: PDGFRα expression was evaluated by qPCR and Western blot analysis. Olaratumab was investigated in in vitro cell proliferation and invasion assays using pediatric osteosarcoma and rhabdoid tumor cell lines. In vivo activity of olaratumab was assessed in preclinical mouse models of pediatric osteosarcoma and malignant rhabdoid tumor.Results:In vitro olaratumab treatment of osteosarcoma and rhabdoid tumor cell lines reduced proliferation and inhibited invasion driven by individual platelet-derived growth factors (PDGFs) or serum. Furthermore, olaratumab delayed primary tumor growth in mouse models of pediatric osteosarcoma and malignant rhabdoid tumor, and this activity was enhanced by combination with either doxorubicin or cisplatin.Conclusions: Overall, these data indicate that olaratumab, alone and in combination with standard of care, blocks the growth of some preclinical PDGFRα-expressing pediatric bone and soft tissue tumor models. Clin Cancer Res; 24(4); 847-57. ©2017 AACR.

"Simple Mucinous Cyst" of the Pancreas: A Clinicopathologic Analysis of 39 Examples of a Diagnostically Challenging Entity Distinct From Intraductal Papillary Mucinous Neoplasms and Mucinous Cystic Neoplasms.

Pancreatic cysts >1 cm lined by nonpapillary mucinous epithelium without ovarian-type stroma pose diagnostic challenges. The term "simple mucinous cyst" was recently proposed for this entity. Our goal was to determine the clinicopathologic characteristics of these cysts, as they have not been previously described. Of the 39 patients with pancreatic resections included in this study, the mean age was 65 years and the female-to-male ratio was 4:1. The characteristics of the cysts are as follows: 82% had elevated cyst fluid carcinoembryonic antigen levels, 67% were unilocular, 69% occurred in the body/tail, 92% did not communicate with pancreatic ducts, the mean size was 2.4 cm (range, 1.0 to 5.5 cm), the cyst contents tended to be serous (48%) or viscous (28%), all had a smooth lining (only 1 had focal excrescences) composed of bland columnar mucinous epithelium (low-grade dysplasia) in 92% with focal high-grade dysplasia in 8%, and 65% had degenerative changes (granulation-like tissue, hemorrhage, and myxoid stroma). The cyst lining was CK7+ and 97% had a MUC5AC+ and/or MUC6+ gastric phenotype; overt intestinal features were absent. In total, 55% of cysts tested (fluid and/or resections) harbored KRAS mutations. The term "simple mucinous cyst" is useful to apply to >1 cm mucinous cysts that do not have characteristic features of intraductal papillary mucinous neoplasms or mucinous cystic neoplasms. KRAS mutations can be detected in these typically bland cysts, and in rare instances, focal high-grade dysplasia may be present. Hence, these cysts should be viewed as neoplastic and treated similarly to other mucinous pancreatic cysts.

HER-2 amplification in tubular carcinoma of the breast.

The prognostic and therapeutic implications of HER-2 gene amplification and estrogen and progesterone receptor status in breast cancer are well described. To address the relative paucity of information concerning HER-2 amplification for tubular carcinomas, we assessed the frequency of gene amplification in 55 tubular carcinomas of the breast from 54 patients, 5 of which had axillary node metastases. The HER-2 gene copy number was assessed by fluorescence in situ hybridization for the majority of tumors analyzed, whereas estrogen and progesterone receptor status was achieved by immunohistochemical analysis. HER-2 gene amplification was not observed in any of the tumors examined, and most were estrogen receptor-positive. This HER-2 gene amplification frequency was significantly lower than the frequency of gene amplification previously reported for all invasive ductal carcinoma of no special type (P < .01). HER-2 gene amplification likely occurs infrequently, or not at all, in tubular carcinomas of the breast, whereas most express estrogen receptors.

Variability in Platelet-Derived Growth Factor Receptor Alpha Antibody Specificity May Impact Clinical Utility of Immunohistochemistry Assays.

Aberrant regulation of the receptor tyrosine kinase platelet-derived growth factor alpha (PDGFRα) is implicated in several types of cancer. Inhibition of the PDGFRα pathway may be a beneficial therapy, and detection of PDGFRα in tumor biopsies may lead to insights about which patients respond to therapy. Exploratory or clinical biomarker use of PDGFRα IHC has been frequently reported, often with polyclonal antibody sc-338. An sc-338-based assay was systematically compared with anti-PDGFRα rabbit monoclonal antibody D13C6 using immunoblot profiling and IHC in formalin-fixed and paraffin-embedded human tumor cell lines. Application of sc-338 to blots of whole cell lysates showed multiple bands including some of unknown origin, whereas application of D13C6 resulted in a prominent band at the expected molecular mass of PDGFRα. The IHC assay using D13C6 showed appropriate staining in cell lines, whereas the assay using sc-338 suggested nonspecific detection of proteins. An optimized IHC assay using D13C6 showed a range of staining in the tumor stromal compartment in lung and ovarian carcinomas. These observations suggest that use of clone sc-338 produced unreliable results and should not be used for an IHC research grade assay. In addition, this precludes its use as a potential antibody for a clinical diagnostic tool.

Same difference: A pilot study of cyclin D1, bcl-2, AMACR, and ALDH-1 identifies significant differences in expression between primary colon adenocarcinoma and its metastases.

Tumor heterogeneity implies the possibility of significantly different expression of key pathways between primary and metastatic clones. Colon adenocarcinoma is one of the few tumors where current practice includes resection of primary and isolated organ metastases simultaneously without neoadjuvant therapy. We performed a pilot study on 28 cases of colon adenocarcinoma resected simultaneously with metastases in patients with no history of neoadjuvant therapy. We assayed matched primary and metastatic tumors from each patient with common diagnostic antibodies to Bcl-2, Cyclin D1, AMACR, and ALDH-1 by immunohistochemistry with semi-quantitative interpretation on archived formalin fixed, paraffin embedded samples. We were powered for large, consistent differences between primary and metastatic expression, and found 21 of 28 had a significant difference in expression of at least one of the four proteins, accounting for multiplicity of testing. Cyclin D1 had significantly more cases with differential metastatic:primary expression than would be expected by chance alone (p-value 0.0043), favoring higher expression in the metastatic sample. Bcl-2 and ALDH-1 had trends in this direction (p-value 0.078 each). Proportionately more cases with significant differences were identified when a liver metastasis was tested. We conclude differences in expression between metastatic and primary colon adenocarcinoma within the same patient exist, and may have therapeutic and biomarker testing consequences.

A novel mutation in the succinate dehydrogenase subunit D gene in siblings with the hereditary paraganglioma-pheochromocytoma syndrome.

Germline mutations in the succinate dehydrogenase complex subunit D gene are now known to be associated with hereditary paraganglioma-pheochromocytoma syndromes. Since the initial succinate dehydrogenase complex subunit D gene mutation was identified about a decade ago, more than 131 unique variants have been reported. We report the case of two siblings presenting with multiple paragangliomas and pheochromocytomas; they were both found to carry a mutation in the succinate dehydrogenase complex subunit D gene involving a substitution of thymine to guanine at nucleotide 236 in exon 3. This particular mutation of the succinate dehydrogenase complex subunit D gene has only been reported in one previous patient in Japan; this is, therefore, the first report of this pathogenic mutation in siblings and the first report of this mutation in North America. With continued screening of more individuals, we will be able to create a robust mutation database that can help us understand disease patterns associated with particular variants and may be a starting point in the development of new therapies for familial paraganglioma syndromes.

Higher dosage of the epidermal growth factor receptor mutant allele in lung adenocarcinoma correlates with younger age, stage IV at presentation, and poorer survival.

INTRODUCTION: The clinical significance of epidermal growth factor receptor (EGFR) mutant allele specific imbalance (MASI) in lung adenocarcinomas is unknown. METHODS: EGFR MASI was characterized by sequencing electropherograms (SEs) and EGFR fluorescence in situ hybridization (FISH) in 96 prospectively tested lung adenocarcinoma patients with a median follow-up of 20 months (all cases were EGFR mutation-positive). RESULTS: In 25 cases, the mutant allele (MA) peak was higher than the wild-type allele (WA) peak, indicating the presence of EGFR MASI (25/96, 26%). The adenocarcinomas with EGFR MASI had a 4.4-fold higher average EGFR/Chromosome Enumeration Probe 7 ratio than carcinomas without MASI (7.9 ± 3.8 versus 1.8 ± 0.6, p = 0.01). A high degree of correlation between the MA/WA ratio (SE) and the EGFR/CEP7 ratio (FISH) (ρ = 0.757, p = 0.003) validated the quantitative nature of SE. Amplification was the most common mechanism of EGFR MASI (13/21, 62%). EGFR MASI was more commonly associated with exon 19 mutations than with exon 21 mutations (19/53, 36%, versus 6/43, 14%, p = 0.015, odds ratio [OR] = 3.4) and in patients younger than 65 years (17/46, 37%, versus 8/50, 16%, p = 0.019, OR = 3.1). Patients with EGFR MASI presented with stage IV disease more frequently (p = 0.01, OR = 3.5) and had a poorer disease-specific survival rate (p = 0.021, 54% versus 83% at 31 months). CONCLUSIONS: EGFR MASI in lung adenocarcinomas can be assessed based on SE and can be used to identify younger patients with more aggressive disease.

The prognostic value of Ki-67, p53, epidermal growth factor receptor, 1p36, 9p21, 10q23, and 17p13 in skull base chordomas.

CONTEXT: Skull base chordomas are rare, locally aggressive, notochord-derived neoplasms for which prognostically relevant biomarkers are not well established. OBJECTIVE: To evaluate whether newly discovered molecular alterations in chordomas have prognostic significance similar to what has been described regarding Ki-67 proliferation index. DESIGN: We conducted a retrospective study of 28 cases of primary clival chordomas. RESULTS: Ki-67 proliferation index 5% or more, p53 accumulation, and epidermal growth factor receptor expression were seen in 32%, 44%, and 8% of chordomas, respectively. 1p loss of heterozygosity (LOH) and/or 1p36 hemizygous deletion was seen in 30% of tumors, while 9p LOH and/or 9p21 homozygous deletion was seen in 21% of cases. Loss of heterozygosity at 10q23 and 17p13 were identified in 57% and 52% of cases, respectively. Ki-67 proliferation index 5% or more and 9p LOH were significantly associated with a shorter overall survival, while homozygous deletion at 9p21 via fluorescence in situ hybridization approached significance. No correlation with survival was found for p53 or epidermal growth factor receptor expression, 1p36 hemizygous deletion, or LOH at 1p, 10q23, or 17p13. CONCLUSIONS: Chordomas with elevated Ki-67 proliferation index or deletion at 9p21 may be at risk for a more aggressive clinical course and shorter survival. These biomarkers may thus be used to improve therapeutic stratification.

Vascular wall invasion in neurofibromatosis-induced aortic rupture.

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disease primarily characterized by cutaneous café au lait macules, benign neurofibromas, and iris hamartomas. A spectrum of vascular abnormalities is associated with NF-1. We present a case of a 49-year-old female with NF-1 and spontaneous rupture of the infrarenal aorta caused by invasion of a neurofibroma and treated with endovascular stent grafting.

Diffuse filiform polyposis with unique histology mimicking familial adenomatous polyposis in a patient without inflammatory bowel disease.

Filiform polyposis is an uncommon entity that is most often encountered in the colon of patients with a history of inflammatory bowel disease (IBD). Filiform polyposis is characterized by a large number of "wormlike" polyps lined by histologically normal colonic mucosa. These polyps can mimic adenomatous polyps. Only rare cases without a history or evidence of IBD have been reported. Neuromuscular and vascular hamartoma of the small bowel is a rare, focal disorder characterized by disorganized smooth muscle fascicles throughout the submucosa accompanied by fibrosis, nerve fibers, ganglion cells, and vessels. To our knowledge, there is only one report of this lesion in the large bowel (cecum), where it presented as a mass. Here we report the case of a 50-year-old man with no known history or symptoms of IBD presenting with filiform polyposis involving the entire colon, clinically mimicking familial adenomatous polyposis, and showing histologic features similar to neuromuscular and vascular hamartoma of the small bowel.