Phase I and Pharmacokinetic Study of Sunitinib in Pediatric Patients with Refractory Solid Tumors: A Children's Oncology Group Study

Department of Pediatrics, University of California, San Francisco School of Medicine, San Francisco, CA 94143-0106, USA.
Clinical Cancer Research (Impact Factor: 8.72). 06/2011; 17(15):5113-22. DOI: 10.1158/1078-0432.CCR-11-0237
Source: PubMed


Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor. The purpose of this study was to determine the recommended phase 2 dose, pharmacokinetics, pharmacodynamic effects, and preliminary antitumor activity of sunitinib in a pediatric population.
Patients who were 2 to 21 years of age with refractory solid tumors were eligible if they had measurable or evaluable disease and met baseline organ function requirements. Patients received sunitinib once daily for 28 days followed by a 14-day break between each cycle. Dose levels of 15 and 20 mg/m(2)/d were evaluated, with dose escalation based on a 3 + 3 design. Sunitinib pharmacokinetics and biomarkers of angiogenesis were also evaluated during the first cycle.
Twenty-three patients were treated (median age 13.9 years; range, 3.9-20.6 years). The most common toxicities were neutropenia, thrombocytopenia, elevated liver transaminases, gastrointestinal symptoms, and fatigue. Two patients developed dose-limiting reductions in cardiac ejection fraction prompting a protocol amendment to exclude patients with previous exposure to anthracyclines or cardiac radiation. In patients without these cardiac risk factors, the maximum tolerated dose (MTD) was 15 mg/m(2)/d. Steady-state plasma concentrations were reached by day 7. No objective responses were observed. Four patients with sarcoma and glioma had stable disease for 2 to 9 cycles.
Cardiac toxicity precluded determination of a recommended dose for pediatric patients with previous anthracycline or cardiac radiation exposure. The MTD of sunitinib for patients without risk factors for cardiac toxicity is 15 mg/m(2)/d for 28 days followed by a 14-day break.

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Available from: Bing Wu, Oct 04, 2015
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    • "In general it has been demonstrated that CEC and CEP kinetics depend on the tumor type, the therapeutic regimen and the specific method for CEC/CEP quantification. An increase, a decrease, and even no change in CECs and CEP kinetics were detected following anti-angiogenic or cytotoxic treatment strategies [8], [18], [37]. "
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    ABSTRACT: Endothelial progenitor cells (CEPs) and circulating endothelial cells (CECs) are potential biomarkers of response to anti-angiogenic treatment regimens. In the current study, we investigated the effect of docetaxel and sunitinib on CEP/CEC kinetics and clinical response in castration resistant prostate cancer (CRPC) patients. Chemonaive patients with CRPC were enrolled in this study to receive either sunitinib (37.5 mg/d), in combination with docetaxel (75 mg/m2) or docetaxel alone. CEP and CEC kinetics were analyzed for every cycle. The primary objective was to compare CEP/CEC pharmacodynamics between both treatment arms. We also investigated if CEC/CEP spikes, induced by MTD docetaxel, are suppressed by sunitinib in patients treated with docetaxel/sunitinib relative to docetaxel monotherapy. A total of 27 patients were enrolled. We observed a significant increase of CEP/CEC (total/viable) counts over time within each cycle (coefficients 0.29233, 0.22092 and 0.26089, respectively; p<0.001). However, no differences between the treatment groups, in terms of CEP and CEC kinetics, were detected. In the docetaxel monotherapy arm 4 (30%) patients responded to therapy with a 50% PSA decline, while 9 (64%) patients showed a PSA decline in the combination group (n.s.). The median PFS in the docetaxel monotherapy group was 3.1 months (2.6-3.6 months, 95% CI) and 6.2 months (4.9-7.4 months, 95% CI; p = 0.062) in the combination arm. Sunitinib/docetaxel was reasonably well tolerated and toxicity manageable. In summary, no significant differences in CEC and CEP kinetics between the treatment arms were observed, although a highly significant increase of CEPs/CECs within each cycle over time was detected. These results mirror the challenge we have to face when employing anti-angiogenic strategies in CRPC. Additional preclinical research is needed to elucidate the underlying molecular mechanisms. However, docetaxel/sunitinib therapy resulted in a better response in terms of PSA decline and a trend towards improved PFS. EudraCT 2007-003705-27.
    PLoS ONE 04/2014; 9(4):e95310. DOI:10.1371/journal.pone.0095310 · 3.23 Impact Factor
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    • "However, the evaluation of sunitinib in the COG phase I and pharmacokinetic study in pediatric patients with refractory solid tumors did not achieve objective responses. Stable disease was reported for one OS patient in this study (Dubois et al., 2011, 2012), but concerns for cardiac toxicity have limited interest in additional trials. Further preclinical testing of these VEGF-targeted agents in combination with conventional chemotherapeutic regimens may enhance the efficacy of these drugs in the treatment of OS tumors. "
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    ABSTRACT: Osteosarcoma, the most common malignant bone tumor of childhood, is a high-grade primary bone sarcoma that occurs mostly in adolescence. Standard treatment consists of surgery in combination with multi-agent chemotherapy regimens. The development and approval of imatinib for Philadelphia chromosome-positive acute lymphoblastic leukemia in children and the fully human monoclonal antibody, anti-GD2, as part of an immune therapy for high-risk neuroblastoma patients have established the precedent for use of targeted inhibitors along with standard chemotherapy backbones. However, few targeted agents tested have achieved traditional clinical endpoints for osteosarcoma. Many biological agents demonstrating anti-tumor responses in preclinical and early-phase clinical testing have failed to reach response thresholds to justify randomized trials with large numbers of patients. The development of targeted therapies for pediatric cancer remains a significant challenge. To aid in the prioritization of new agents for clinical testing, the Pediatric Preclinical Testing Program (PPTP) has developed reliable and robust preclinical pediatric cancer models to rapidly screen agents for activity in multiple childhood cancers and establish pharmacological parameters and effective drug concentrations for clinical trials. In this article, we examine a range of standard and novel agents that have been evaluated by the PPTP, and we discuss the preclinical and clinical development of these for the treatment of osteosarcoma. We further demonstrate that committed resources for hypothesis-driven drug discovery and development are needed to yield clinical successes in the search for new therapies for this pediatric disease.
    Frontiers in Oncology 05/2013; 3:132. DOI:10.3389/fonc.2013.00132
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    • "They found that a significant correlation between treatment with sunitinib and decreased plasma levels of endoglin, a marker of tumor-associated endothelial cells. This result suggests that following endoglin levels might be used in pharmacodynamic monitoring of sunitinib treatment in children (Dubois et al., 2011). There has also been a study in children with recurrent high-grade gliomas in which patients received a combination of cytotoxic chemotherapy (mostly with irinotecan) and bevacizumab. "
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    ABSTRACT: Brain tumors are the most common solid pediatric malignancy. For high-grade, recurrent or refractory pediatric brain tumors, radiation therapy (XRT) is an integral treatment modality. In the era of personalized cancer therapy, molecularly targeted agents have been designed to inhibit pathways critical to tumorigenesis. Our evolving knowledge of genetic aberrations in low-grade gliomas is being exploited with targeted inhibitors. These agents are also being combined with XRT to increase their efficacy. In this review, we discuss novel agents targeting three different pathways in low-grade gliomas, and their potential combination with XRT. B-Raf is a kinase in the Ras/Raf/MAPK kinase pathway, which is integral to cellular division, survival and metabolism. In low-grade pediatric gliomas, point mutations in BRAF (BRAF V600E) or a BRAF fusion mutation (KIAA1549:BRAF) causes overactivation of the MEK/MAPK pathway. Pre-clinical data shows cooperation between XRT and tagrgeted inhibitors of BRAF V600E, and MEK and mTOR inhibitors in the gliomas with the BRAF fusion. A second important signaling cascade in pediatric glioma pathogenesis is the PI3 kinase (PI3K)/mTOR pathway. Dual PI3K/mTOR inhibitors are poised to enter studies of pediatric tumors. Finally, many brain tumors express potent stimulators of angiogenesis. Several inhibitors of immunomodulators are currently being evaluated in in clinical trials for the treatment of recurrent or refractory pediatric central nervous system (CNS) tumors. In summary, combinations of these targeted inhibitors with radiation are currently under investigation in both translational bench research and early clinical trials. We summarize the molecular rationale for, and the pre-clinical data supporting the combinations of these targeted agents with other anti-cancer agents and XRT in pediatric gliomas. Parallels are drawn to adult gliomas, and the molecular mechanisms underlying the efficacy of these agents is discussed
    Frontiers in Oncology 05/2013; 3:110. DOI:10.3389/fonc.2013.00110
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