Robert L. Ilaria

Olaratumab and doxorubicin versus doxorubicin alone for treatment of soft-tissue sarcoma: an open-label phase 1b and randomised phase 2 trial

BACKGROUND Treatment with doxorubicin is a present standard of care for patients with metastatic soft-tissue sarcoma and median overall survival for those treated is 12-16 months, but few, if any, novel treatments or chemotherapy combinations have been able to improve these poor outcomes. Olaratumab is a human antiplatelet-derived growth factor receptor α monoclonal antibody that has antitumour activity in human sarcoma xenografts. We aimed to assess the efficacy of olaratumab plus doxorubicin in patients with advanced or metastatic soft-tissue sarcoma. METHODS We did an open-label phase 1b and randomised phase 2 study of doxorubicin plus olaratumab treatment in patients with unresectable or metastatic soft-tissue sarcoma at 16 clinical sites in the USA. For both the phase 1b and phase 2 parts of the study, eligible patients were aged 18 years or older and had a histologically confirmed diagnosis of locally advanced or metastatic soft-tissue sarcoma not previously treated with an anthracycline, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, and available tumour tissue to determine PDGFRα expression by immunohistochemistry. In the phase 2 part of the study, patients were randomly assigned in a 1:1 ratio to receive either olaratumab (15 mg/kg) intravenously on day 1 and day 8 plus doxorubicin (75 mg/m(2)) or doxorubicin alone (75 mg/m(2)) on day 1 of each 21-day cycle for up to eight cycles. Randomisation was dynamic and used the minimisation randomisation technique. The phase 1b primary endpoint was safety and the phase 2 primary endpoint was progression-free survival using a two-sided α level of 0.2 and statistical power of 0.8. This study was registered with ClinicalTrials.gov, number NCT01185964. FINDINGS 15 patients were enrolled and treated with olaratumab plus doxorubicin in the phase 1b study, and 133 patients were randomised (66 to olaratumab plus doxorubicin; 67 to doxorubicin alone) in the phase 2 trial, 129 (97%) of whom received at least one dose of study treatment (64 received olaratumab plus doxorubicin, 65 received doxorubicin). Median progression-free survival in phase 2 was 6.6 months (95% CI 4.1-8.3) with olaratumab plus doxorubicin and 4.1 months (2.8-5.4) with doxorubicin (stratified hazard ratio [HR] 0.67; 0.44-1.02, p=0.0615). Median overall survival was 26.5 months (20.9-31.7) with olaratumab plus doxorubicin and 14.7 months (9.2-17.1) with doxorubicin (stratified HR 0.46, 0.30-0.71, p=0.0003). The objective response rate was 18.2% (9.8-29.6) with olaratumab plus doxorubicin and 11.9% (5.3-22.2) with doxorubicin (p=0.3421). Steady state olaratumab serum concentrations were reached during cycle 3 with mean maximum and trough concentrations ranging from 419 μg/mL (geometric coefficient of variation in percentage [CV%] 26.2) to 487 μg/mL (CV% 33.0) and from 123 μg/mL (CV% 31.2) to 156 μg/mL (CV% 38.0), respectively. Adverse events that were more frequent with olaratumab plus doxorubicin versus doxorubicin alone included neutropenia (37 [58%] vs 23 [35%]), mucositis (34 [53%] vs 23 [35%]), nausea (47 [73%] vs 34 [52%]), vomiting (29 [45%] vs 12 [18%]), and diarrhoea (22 [34%] vs 15 [23%]). Febrile neutropenia of grade 3 or higher was similar in both groups (olaratumab plus doxorubicin: eight [13%] of 64 patients vs doxorubicin: nine [14%] of 65 patients). INTERPRETATION This study of olaratumab with doxorubicin in patients with advanced soft-tissue sarcoma met its predefined primary endpoint for progression-free survival and achieved a highly significant improvement of 11.8 months in median overall survival, suggesting a potential shift in the treatment of soft-tissue sarcoma. FUNDING Eli Lilly and Company.

Expression of the EWS/FLI-1 Oncogene in Murine Primary Bone-Derived Cells Results in EWS/FLI-1–Dependent, Ewing Sarcoma–Like Tumors

Ewing sarcoma is the second most common malignant pediatric bone tumor. Over 80% of Ewing sarcoma contain the oncogene EWS/FLI-1, which encodes the EWS/FLI-1 oncoprotein, a hybrid transcription factor comprised of NH2-terminal sequences from the RNA-binding protein EWS and the DNA-binding and COOH-terminal regions of the Ets transcription factor FLI-1. Although numerous genes are dysregulated by EWS/FLI-1, advances in Ewing sarcoma cancer biology have been hindered by the lack of an animal model because of EWS/FLI-1-mediated cytotoxicity. In this study, we have developed conditions for the isolation and propagation of murine primary bone-derived cells (mPBDC) that stably express EWS/FLI-1. Early-passage EWS/FLI-1 mPBDCs were immortalized in culture but inefficient at tumor induction, whereas later-passage cells formed sarcomatous tumors in immunocompetent syngeneic mice. Murine EWS/FLI-1 tumors contained morphologically primitive cells that lacked definitive lineage markers. Molecular characterization of murine EWS/FLI-1 tumors revealed that some but not all had acquired a novel, clonal in-frame p53 mutation associated with a constitutive loss of p21 expression. Despite indications that secondary events facilitated EWS/FLI-1 mPBDC tumorigenesis, cells remained highly dependent on EWS/FLI-1 for efficient transformation in clonogenic assays. This Ewing sarcoma animal model will be a useful tool for dissecting the molecular pathogenesis of Ewing sarcoma and provides rationale for the broader use of organ-specific progenitor cell populations for the study of human sarcoma.

Alteration of mesodermal cell differentiation by EWS/FLI-1, the oncogene implicated in Ewing's sarcoma.

ABSTRACT The chimeric fusion gene EWS/FLI-1 is detected in most cases of Ewings sarcoma (ES), the second most common malignant bone tumor of childhood. Although 80% of ES tumors develop in skeletal sites, the remainder can arise in almost any soft tissue location. The lineage of the cell developing the EWS/FLI-1 gene fusion has not been fully characterized but is generally considered to be of either mesenchymal or neural crest origin. To study this oncogene in a conceptually relevant target cell, EWS/FLI-1 was introduced into the murine cell line C2C12, a myoblast cell line capable of differentiation into muscle, bone, or fat. In this cellular context, EWS/FLI-1 profoundly inhibited the myogenic differentiation program. The block in C2C12 myogenic differentiation required the nuclear localization and DNA-binding functions of EWS/FLI-1 and was mediated by transcriptional and posttranscriptional suppression of the myogenic transcription factors MyoD and myogenin. Interestingly, C2C12-EWS/FLI-1 cells constitutively expressed alkaline phosphatase, a bone lineage marker, and were alkaline phosphatase positive by histochemistry but showed no other evidence of bone lineage commitment. Consistent with recent findings in human ES tumor cell lines, C2C12-EWS/FLI-1 cells constitutively expressed cyclin D1 and demonstrated decreased expression of the cell cycle regulator p21cip1, even under differentiation conditions and at confluent density. This C2C12-EWS/FLI-1 cell model may assist in the identification of novel differentially expressed genes relevant to ES and provide further insight into the cell(s) of origin developing ES-associated genetic fusions.

Imatinib Mesylate Efficiently Achieves Therapeutic Intratumor Concentrations in Vivo but Has Limited Activity in a Xenograft Model of Small Cell Lung Cancer

Purpose: Despite recent advances in cancer therapy, long-term survival in small cell lung cancer (SCLC) remains uncommon, underscoring the need for novel therapeutic approaches. Previous studies have identified constitutive expression of the receptor tyrosine kinase, c-Kit, and its ligand, stem cell factor, in a substantial proportion of SCLC specimens. The purpose of this study was to determine whether imatinib mesylate, an inhibitor of c-Kit, could achieve therapeutic concentrations in tumors and in brain (a frequent site of SCLC metastasis) and interfere with SCLC tumor growth in vivo. Experimental Design: Human SCLC tumor cell lines with constitutive c-kit expression and tyrosine phosphorylation (NCI-H209, NCI-H526, and NCI-H1607) were used to establish SCLC tumor xenografts in NCr nude (nu/nu)-immunodeficient mice. SCLC tumor-bearing mice were randomly assigned to imatinib or control (water) administered twice a day by oral gavage. Imatinib concentrations in plasma, brain, and tumor were quantitated and correlated with tumor response. Results: Therapeutic concentrations of imatinib were achieved in plasma and tumor xenografts but not in the brain. Imatinib blocked the constitutive activation of c-kit in SCLC tumor cell lines in vitro but had a negligible effect on SCLC xenograft growth in vivo. Conclusions: Orally administered imatinib rapidly reaches therapeutic concentrations in SCLC xenografts, suggesting the feasibility of combining imatinib with other novel or traditional chemotherapeutic agents in SCLC or other solid tumors. The c-Kit signaling pathway does not appear to play a critical role in SCLC proliferation and viability in vivo, however, suggesting that imatinib is unlikely to be effective as monotherapy for SCLC.

Interference with the constitutive activation of ERK1 and ERK2 impairs EWS/FLI-1-dependent transformation.

The chimeric gene EWS/FLI-1, the hallmark of the Ewings sarcoma and primitive neuroectodermal tumor family, encodes a fusion protein with enhanced transcriptional activation properties and preserved recognition of canonical ETS binding sites. Although EWS/FLI-1 alters the expression of various genes, the precise mechanism by which EWS/FLI-1 acts as an oncogene remains to be defined. In this study we report that members of the mitogen-activated protein kinase (MAPK) signaling pathway, ERK1 and ERK2, are constitutively activated in NIH 3T3 cells expressing EWS/FLI-1. Interference with ERK activation by either highly specific inhibitors of MEK1 or a dominant negative ras mutant profoundly impaired the ability of EWS/FLI-1 to transform NIH3T3 cells to growth in semi-solid medium. An EWS/FLI-1 mutant defective in DNA-binding and transcriptional activation failed to activate ERK and was also defective in 3T3 cell transformation. Constitutive ERK activation was also evident in several human Ewings sarcoma tumor-derived cell lines. Interestingly, cells expressing the type II EWS/FLI-1 fusion, recently demonstrated more potent in transcriptional activation, showed even greater MAPK activation than cells expressing the more common type I fusion. These results implicate ERK activation in EWS/FLI-1 transformation and suggest that this signaling pathway may be important in the pathogenesis of Ewings sarcoma.

A phase 2 study of tasisulam sodium (LY573636 sodium) as second-line treatment for patients with unresectable or metastatic melanoma†‡

Tasisulam sodium (hereafter, tasisulam) is a novel anticancer agent that induces apoptosis through the intrinsic pathway and has antiangiogenic activity in preclinical models. Tasisulam demonstrated activity across a broad range of tumors, including melanoma. The primary objective of this phase 2 study was to determine the objective response rate (ORR) in patients who had received 1 previous systemic chemotherapy for unresectable/metastatic melanoma; secondary objectives were to evaluate the clinical response rate (CRR), progression‐free survival (PFS), overall survival (OS), duration of response, safety, and pharmacokinetics.

The epidermal growth factor receptor HER2 is not a major therapeutic target in Ewing sarcoma

Background Although chimeric EWS gene and Ets gene fusions are pathognomonic of Ewing sarcoma (ES) and primitive neuroectodermal tumors (PNET), the molecular pathogenesis of these pediatric malignancies is poorly understood. Recently, the human epidermal growth factor (HER)-2 receptor, which plays an important role in the biology of certain epithelial cancers, has been implicated in ES tumor cell line growth and chemosensitivity. Materials To investigate whether HER2 might be a rational target for ES/PNET therapy, five ES cell lines and 13 archival primary ES/PNET samples were examined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for evidence of HER2 overexpression. Results Although several ES cell lines demonstrated modest constitutive HER2 expression by immunoblot, none of the ES cell lines or primary tumor samples showed evidence of HER2 overexpression by IHC or HER2 gene amplification by FISH. Moreover, treatment of human ES cell lines with the HER2-targeted agent trastuzumab (Herceptin) had little effect on cell survival, proliferation, or growth in semi-solid medium. Conclusions These results suggest that HER2 is not a biologically or therapeutically important pathway in ES/PNET.

Tasisulam Sodium (LY573636 Sodium) as Third-Line Treatment in Patients With Unresectable, Metastatic Non–Small-Cell Lung Cancer: A Phase-II Study

Introduction: Tasisulam sodium (hereafter referred to as tasisulam) is a novel anticancer compound that induces apoptosis and exhibits antiangiogenesis activity in a broad range of cancer models, including non–small-cell lung cancer (NSCLC). Methods: Tasisulam was administered as a 2-hour infusion every 21 days as third-line treatment in patients with advanced (stage IIIB/IV) NSCLC. Results: Thirty-two patients received a Cmax target dose of 420 µg/ml. Median time to progression was 3.12 months, median progression-free survival was 2.69 months, and median overall survival was 8.48 months. There were no objective responses; 43.8% of patients achieved stable disease. A high rate of grade-4 hematologic toxicity in the first 30 patients led to exploration of a lower Cmax target dose of 380 µg/ml. The rate of grade-4 hematologic toxicity (thrombocytopenia and/or neutropenia) at the 380-µg/ml dose (n = 20) was 20% versus 34% at the 420-µg/ml dose. Conclusions: Tasisulam has only modest activity as a third-line treatment of patients with unresectable/metastatic NSCLC. The high rate of grade-4 hematologic toxicity observed with this highly albumin– bound compound in this patient population provided challenges for fixed Cmax-based dosing. Alternative dosing methods, including varying the Cmax target dose by predose albumin, are under investigation in other studies.

Bcr/Abl, leukemogenesis, and genomic instability: a complex partnership

For many years, the issue of genomic instability in chronic myelogenous leukemia (CML) has been one of “guilt by association”. Even before much of the molecular pathophysiology of CML was known, investigators had noted that patients with advanced CML acquired additional cytogenetic abnormalities. Interestingly, there is a relatively short list of common secondary chromosomal cytogenetic changes, including an additional copy of the Philadelphia chromosome, trisomy 8, trisomy 19, isochromosome 17q, and loss of the Y chromosome [1]. Transgenic mice expressing the P190 form of BCR/ABL have also been shown to develop karyotypic abnormalities during the later stages of their leukemic illness, most commonly trisomy involving chromosomes 12, 14, or 17, alone or in combination [2]. Prolonged expression of the P210 form of BCR/ABL in the murine myeloid cell line 32D has been demonstrated to be associated with the development of aneuploidy and complex chromosomal translocations [3]. These and other findings have led investigators to postulate that Bcr/Abl expression itself might be responsible to such secondary genetic changes. Proving such a connection, however, is a complex challenge. Solid tumors often demonstrate a variety of cytogenetic abnormalities [4], most of which are likely the consequence, rather than the cause, of malignant transformation. Therefore, it is conceivable that the additional cytogenetic abnormalities seen in CML could merely reflect stochastic changes due to a prolonged leukemia process. Alternatively, given the impact of Bcr/Abl on factors regulating cell survival, apoptosis, and DNA repair, the hypothesis that Bcr/Abl itself could lead to genomic instability independent of its leukemogenic effect is of considerable interest. One recent approach to this question has been to mate P190BCR/ABL transgenic mice [5] with the transgenic strain

Phase II study of olaratumab with paclitaxel/carboplatin (P/C) or P/C alone in previously untreated advanced NSCLC

BACKGROUND In non-small cell lung cancer (NSCLC), platelet-derived growth factor receptor (PDGFR) mediates angiogenesis, tissue invasion, and tumor interstitial pressure. Olaratumab (IMC-3G3) is a fully human anti-PDGFRα monoclonal antibody. This Phase II study assessed safety and efficacy of olaratumab+paclitaxel/carboplatin (P/C) versus P/C alone for previously untreated advanced NSCLC. MATERIALS AND METHODS Patients received up to six 21-day cycles of P 200mg/m2 and C AUC 6 (day 1)±olaratumab 15mg/kg (days 1 and 8). Primary endpoint was PFS. Olaratumab was continued in the olaratumab+P/C arm until disease progression. RESULTS 131 patients were: 67 with olaratumab+P/C and 64 with P/C; 74% had nonsquamous NSCLC. Median PFS was similar between olaratumab+P/C and P/C (4.4 months each) (HR 1.29; 95% CI [0.86-1.93]; p=0.21). Median OS was similar between olaratumab+P/C (11.8 months) and P/C (11.5 months) (HR 1.04; 95% CI [0.68-1.57]; p=0.87). Both arms had similar toxicity profiles. All evaluable cases were PDGFR-negative by immunohistochemistry. Tumor stroma PDGFR expression was evaluable in 23/131 patients, of which 78% were positive. CONCLUSIONS The addition of olaratumab to P/C did not result in significant prolongation of PFS or OS in advanced NSCLC. Olaratumab studies in other patient populations, including soft tissue sarcoma (NCT02783599), pancreatic cancer (NCT03086369), and pediatric malignancies (NCT02677116) are underway.