Stephen A Welch

London Health Sciences Centre, London, Ontario, Canada

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Publications (12)45.8 Total impact

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    ABSTRACT: Treatment options remain limited for women with relapsed/metastatic endometrial cancer (EC). Angiogenesis is one of the major components of tumor progression and thus an attractive target. The aim of this phase II trial was to assess the efficacy and tolerability of sunitinib, an oral multitargeted receptor tyrosine-kinase inhibitor with antiangiogenic and antitumor activity in the treatment of recurrent EC.
    Gynecologic oncology. 05/2014;
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    ABSTRACT: Objective The phosphatidylinositol-3 kinase/serine-threonine kinase PI3K/AKT pathway is postulated to be central to cancer cell development. Activation of this pathway is believed to promote angiogenesis, protein translation and cell cycle progression. A large percentage of endometrial carcinomas have demonstrated mutations within this regulation pathway which result in constitutional activation. The downstream effector protein mammalian target of rapamycin (mTOR) acts as a critical checkpoint in cancer cell cycling and is a logical target for drug development. The efficacy and tolerability of the oral mTOR inhibitor Ridaforolimus was evaluated in this study. Methods This phase II study evaluated the single agent tolerability and activity of oral ridaforolimus administered at a dose of 40 mg for 5 consecutive days followed by a 2 day break, in women with recurrent or metastatic endometrial carcinoma who had received no chemotherapy in the metastatic setting. Results 31 of 34 patients were evaluable. Three partial responses (8.8%) were observed with response duration ranging between 7.9-26.5 months. An additional 18 patients showed disease stabilisation (52.9%) for a median duration of 6.6 months. Response rates were not affected by previous chemotherapy exposure. No correlation was found between response and mutation status. Conclusion Oral Ridaforolimus was reasonably tolerated and demonstrated modest activity in women with recurrent or metastatic endometrial cancers. Potential synergy between mTOR inhibition, angiogenesis and hormonal pathways warrants ongoing evaluation.
    Gynecologic Oncology. 01/2014;
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    ABSTRACT: Developments in genomics, including next-generation sequencing technologies, are expected to enable a more personalized approach to clinical care, with improved risk stratification and treatment selection. In oncology, personalized medicine is particularly advanced and increasingly used to identify oncogenic variants in tumor tissue that predict responsiveness to specific drugs. Yet, the translational research needed to validate these technologies will be conducted in patients with late-stage cancer and is expected to produce results of variable clinical significance and incidentally identify genetic risks. To explore the experiential context in which much of personalized cancer care will be developed and evaluated, we conducted a qualitative interview study alongside a pilot feasibility study of targeted DNA sequencing of metastatic tumor biopsies in adult patients with advanced solid malignancies. We recruited 29/73 patients and 14/17 physicians; transcripts from semi-structured interviews were analyzed for thematic patterns using an interpretive descriptive approach. Patient hopes of benefit from research participation were enhanced by the promise of novel and targeted treatment but challenged by non-findings or by limited access to relevant trials. Family obligations informed a willingness to receive genetic information, which was perceived as burdensome given disease stage or as inconsequential given faced challenges. Physicians were optimistic about long-term potential but conservative about immediate benefits and mindful of elevated patient expectations; consent and counseling processes were expected to mitigate challenges from incidental findings. These findings suggest the need for information and decision tools to support physicians in communicating realistic prospects of benefit, and for cautious approaches to the generation of incidental genetic information.European Journal of Human Genetics advance online publication, 17 July 2013; doi:10.1038/ejhg.2013.158.
    European journal of human genetics: EJHG 07/2013; · 3.56 Impact Factor
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    ABSTRACT: OBJECTIVE: HPV infection has been associated with deregulation of the PI3K-Akt-mTOR pathway in invasive cervical carcinomas. This 2-stage phase II study assessed the activity of the mTOR inhibitor, temsirolimus, in patients with measurable metastatic and/or locally advanced, recurrent carcinoma of the cervix. METHODS: Temsirolimus 25 mg i.v. was administered weekly in 4 week cycles. One response amongst the first 18 patients was required to proceed to the second stage of accrual. Correlative molecular studies were performed on archival tumour tissue. RESULTS: Thirty-eight patients were enrolled. Thirty-seven patients were evaluable for toxicity and 33 for response. One patient experienced a partial response (3.0%). Nineteen patients had stable disease (57.6%) [median duration 6.5 months (range 2.4-12.0 mo)]. The 6-month progression free survival rate was 28% (95% CI: 14-43%). The median progression free survival was 3.52 months [95% CI (1.81-4.70)]. Adverse effects were mild-moderate in most cases and similar to other temsirolimus studies. No toxicity > grade 3 was observed. Assessment of PTEN and PIK3CA by IHC, copy number analyses and PTEN promoter methylation status did not reveal subsets associated with disease stability. CONCLUSION: Single agent temsirolimus has modest activity in cervical carcinoma with about two-thirds of patients exhibiting stable disease. Molecular markers for treatment benefit remain to be identified.
    Gynecologic Oncology 05/2013; · 3.93 Impact Factor
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    ABSTRACT: The successes of targeted drugs with companion predictive biomarkers and the technological advances in gene sequencing have generated enthusiasm for evaluating personalized cancer medicine strategies using genomic profiling. We assessed the feasibility of incorporating real-time analysis of somatic mutations within exons of 19 genes into patient management. Blood, tumor biopsy and archived tumor samples were collected from 50 patients recruited from four cancer centers. Samples were analyzed using three technologies: targeted exon sequencing using Pacific Biosciences PacBio RS, multiplex somatic mutation genotyping using Sequenom MassARRAY and Sanger sequencing. An expert panel reviewed results prior to reporting to clinicians. A clinical laboratory verified actionable mutations. Fifty patients were recruited. Nineteen actionable mutations were identified in 16 (32%) patients. Across technologies, results were in agreement in 100% of biopsy specimens and 95% of archival specimens. Profiling results from paired archival/biopsy specimens were concordant in 30/34 (88%) patients. We demonstrated that the use of next generation sequencing for real-time genomic profiling in advanced cancer patients is feasible. Additionally, actionable mutations identified in this study were relatively stable between archival and biopsy samples, implying that cancer mutations that are good predictors of drug response may remain constant across clinical stages.
    International Journal of Cancer 09/2012; · 6.20 Impact Factor
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    ABSTRACT: Previous phase III studies raised concern about the safety of the combination of capecitabine and irinotecan in patients with metastatic colorectal cancer (mCRC). We conducted a single arm phase II study to evaluate the safety and efficacy of bevacizumab in combination with dose-reduced capecitabine and irinotecan in patients with previously untreated mCRC. Patients with previously untreated mCRC were eligible. Capecitabine was given at 1,000 mg/m2 orally twice daily for 14 days and dose was reduced to 750 mg/m2 for patients over 65. Irinotecan was given at 200 mg/m2 and bevacizumab was given at 7.5 mg/kg intravenously on day 1. The treatment cycle was repeated every 21 days. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival, response rate, and toxicity. Fifty patients were enrolled, the median age was 58, and 54% were ECOG 0. The most common grade 3/4 adverse events included hand-foot syndrome (14%), neutropenia (12%), and diarrhea (10%). Response rate was 51% and disease control rate (response and stable disease) was 98%. Median PFS was 11.5 months (95% CI: 9.2-13.7), and 6 month PFS was 90% (95% CI: 77-98%). With modest dose reductions, the combination of capecitabine, irinotecan, and bevacizumab was well tolerated and resulted in favorable outcomes for patients with previously untreated mCRC.
    Cancer Chemotherapy and Pharmacology 02/2012; 69(5):1339-44. · 2.80 Impact Factor
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    ABSTRACT: Antiangiogenic strategies have demonstrated efficacy in epithelial ovarian cancer (EOC). Sorafenib is a novel multitargeted kinase inhibitor with antiangiogenic activity. Gemcitabine has known activity against EOC. A phase 1 clinical trial of this combination suggested activity in ovarian cancer with no dose-limiting toxicity. This phase 2 study was designed to examine the safety and efficacy of gemcitabine and sorafenib in patients with recurrent EOC. Patients with recurrent EOC after platinum-based chemotherapy and who had subsequently received up to 3 prior chemotherapy regimens were eligible. Gemcitabine (1000 mg/m intravenous [IV]) was administered weekly for 7 of 8 weeks in the first cycle, then weekly for 3 weeks of each subsequent 4-week cycle. Sorafenib (400 mg p.o. bid) was given continuously. The primary end point for this trial was objective response rate by the Response Evaluation Criteria in Solid Tumors. Secondary endpoints included Gynecologic Cancer Intergroup (GCIG) CA-125 response, time to progression, overall survival, and toxicity. Forty-three patients were enrolled, and 33 completed at least 1 cycle. Two patients had a partial response (Response Evaluation Criteria in Solid Tumors objective response rate = 4.7%). Ten patients (23.3%) maintained response or stable disease for at least 6 months. GCIG CA-125 response was 27.9%. The median time to progression was 5.4 months, and the median overall survival was 13.0 months. Hematologic toxicity was common but manageable. The most common nonhematologic adverse events were hand-foot syndrome, fatigue, hypokalemia, and diarrhea. This trial of gemcitabine and sorafenib in recurrent EOC did not meet its primary efficacy end point, but the combination was associated with encouraging rates of prolonged stable disease and CA-125 response.
    International Journal of Gynecological Cancer 07/2010; 20(5):787-93. · 1.94 Impact Factor
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    ABSTRACT: Dynamic allocation (DA) methods which attempt to balance baseline prognostic factors between treatment arms, can be used in multi-arm clinical trials to sequentially allocate patients to treatment. Although some experts express concern regarding the validity of inference from trials using DA, others believe DA methods produce more credible results. A review of published multi-arm cancer clinical trials was conducted to explore the frequency of DA use in oncology. Multi-arm phase III clinical trials of at least 100 patients per arm, published in 13 major oncology journals from 1995-2005 were manually reviewed. Information about reported use of DA methods, or randomization via random permuted blocks (PB), was extracted along with trial characteristics. Of 476 published clinical trials, 112 (23.5%) reported using some form of DA method, while 103 (21.6%) reported using PB methods. Most trials (403 or 84.7%) reported stratifying on at least one baseline factor. The mean number of stratification factors was 2.70 per trial, and 78.6% of DA trials reported 3 or more stratification factors compared with 30.2% of non-DA trials (p < 0.001). The frequency of DA use increased over time, with 20.2%, 21.3%, 25.8%, 28.8% and 38.9% of trials reported use in 1995-2001, 2002, 2003, 2004, and 2005, respectively. Use of DA methods was more frequently reported in trials involving an academic co-operative group (28.4% vs. 13.8%), however, no difference was observed between industry-funded and other-funded trials (24.0% vs. 23.2%) or geographical region (19.7% of North American trials, 26.2% of European trials and 21.7% of multinational/other trials). As a retrospective analysis, the true frequency of DA use is likely underreported. Few trials gave complete details of the allocation method used, thus it is possible some manuscripts reported incorrect allocation methods. Journals were selected which were assumed to publish most large, multi-arm clinical trials in cancer from 1995-2005, however, some trials were likely reported in journals other than what was reviewed. DA methods are frequently used in multi-arm cancer clinical trials. The use of DA appears to becoming more common over time and are used more frequently when an academic cooperative group is involved. No relationship between industry funded trials or geographic region and allocation method was observed. Clinical Trials 2010; 7: 227-234. http://ctj.sagepub.com.
    Clinical Trials 06/2010; 7(3):227-34. · 2.20 Impact Factor
  • Stephen A Welch, Amit M Oza
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    ABSTRACT: Effective agents with a favorable toxicity profile are needed for women with advanced ovarian cancer. PEGylated liposomal doxorubicin (PLD) is safe and effective as monotherapy for advanced ovarian cancer. It was compared with topotecan in a large Phase III trial in this patient population and was found to be associated with less severe adverse events. In platinum-sensitive patients, PLD was associated with a statistically significant survival advantage over topotecan. PLD is currently under further investigation to expand its role in the treatment of ovarian cancer into combination regimens with carboplatin as first-line treatment, as maintenance therapy as a single-agent, and in combination with molecularly targeted agents in the salvage setting.
    Expert Review of Obstetrics &amp Gynecology 12/2007; 3(1):21-31.
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    ABSTRACT: UCN-01 is a staurosporine analogue shown to abrogate the G2 checkpoint through inhibition of cyclin-dependent kinases. Preclinical evidence suggests synergy between UCN-01 and cytotoxic chemotherapy. Topotecan is an active agent in ovarian cancer. This phase II study was conducted to investigate the safety and efficacy of topotecan and UCN-01 in patients with advanced ovarian cancer. A two-stage phase II trial was designed for patients with advanced ovarian cancer with progressive disease despite prior treatment with platinum and paclitaxel. Patients with advanced ovarian cancer were treated with topotecan, 1 mg/m(2) IV, days 1 to 5, and UCN-01 70 mg/m(2) on day 1 of the first cycle, and 35 mg/m(2) on day 1 of all subsequent cycles. Treatment was repeated on a 3-week cycle. The primary objective of this study was objective response rate while secondary objectives included rates of stable disease, duration of response, progression-free and overall survival, as well as toxicity. Tumor biopsy specimens were also collected where possible for molecular correlative studies. Twenty-nine patients are evaluable for toxicity and efficacy. Three patients (10%) achieved a partial response. The median time to progression was 3.3 months (95% CI 1.5-NA), and the median overall survival was 9.7 months (95% CI: 7.5-15.3). The most common grade 3-4 toxicities were neutropenia (79%), anemia (41%), thrombocytopenia (14%), hyperglycemia (10%), and pain (10%). The combination of UCN-01 and topotecan is generally well tolerated, however, this combination is not considered to have significant antitumor activity against advanced ovarian cancer.
    Gynecologic Oncology 09/2007; 106(2):305-10. · 3.93 Impact Factor
  • Stephen A Welch, Malcolm J Moore
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    ABSTRACT: Epidermal growth factor receptor (EGFR) is overexpressed by several solid tumors, including pancreatic cancer, and has become an important target for novel anticancer pharmacotherapy. Erlotinib (Tarceva, OSI-774) is an orally available small-molecule inhibitor of the EGFR tyrosine kinase. The addition of erlotinib to gemcitabine has been shown to prolong survival of patients treated for advanced pancreatic cancer in the National Cancer Institute of Canada PA.3 trial. This survival advantage is small yet noteworthy, in that numerous gemcitabine-containing combinations have failed to show a statistically significant survival advantage over gemcitabine alone. The most frequent toxicities associated with the addition of erlotinib are diarrhea and rash. Erlotinib-induced rash appears to be predictive of outcome. Further clinical studies of erlotinib in the treatment of pancreatic cancer are ongoing.
    Future Oncology 07/2007; 3(3):247-54. · 3.20 Impact Factor
  • Stephen A Welch, Malcolm J Moore
    Journal of Clinical Oncology 07/2007; 25(16):2159-61. · 18.04 Impact Factor

Publication Stats

103 Citations
45.80 Total Impact Points

Institutions

  • 2012–2014
    • London Health Sciences Centre
      London, Ontario, Canada
    • Regional Integration Cancer Center
      Мендоса, Mendoza, Argentina
  • 2010
    • University of Toronto
      Toronto, Ontario, Canada
  • 2007
    • The Princess Margaret Hospital
      Toronto, Ontario, Canada