Laura Quan Man Chow

Sunitinib: From Rational Design to Clinical Efficacy

Sunitinib (SU011248) is an oral small molecular tyrosine kinase inhibitor that exhibits potent antiangiogenic and antitumor activity. Tyrosine kinase inhibitors such as SU6668 and SU5416 (semaxanib) demonstrated poor pharmacologic properties and limited efficacy; therefore, sunitinib was rationally designed and chosen for its high bioavailability and its nanomolar-range potency against the antiangiogenic receptor tyrosine kinases (RTKs)--vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). Sunitinib inhibits other tyrosine kinases including, KIT, FLT3, colony-stimulating factor 1 (CSF-1), and RET, which are involved in a number of malignancies including small-cell lung cancer, GI stromal tumors (GISTs), breast cancer, acute myelogenous leukemia, multiple endocrine neoplasia types 2A and 2B, and familial medullary thyroid carcinoma. Sunitinib demonstrated robust antitumor activity in preclinical studies resulting not only in tumor growth inhibition, but tumor regression in models of colon cancer, non-small-cell lung cancer, melanoma, renal carcinoma, and squamous cell carcinoma, which were associated with inhibition of VEGFR and PDGFR phosphorylation. Clinical activity was demonstrated in neuroendocrine, colon, and breast cancers in phase II studies, whereas definitive efficacy has been demonstrated in advanced renal cell carcinoma and in imatinib-refractory GISTs, leading to US Food and Drug Administration approval of sunitinib for treatment of these two diseases. Studies investigating sunitinib alone in various tumor types and in combination with chemotherapy are ongoing. The clinical benchmarking of this small-molecule inhibitor of members of the split-kinase domain family of RTKs will lead to additional insights regarding the biology, potential biomarkers, and clinical utility of agents that target multiple signaling pathways in tumor, stromal, and endothelial compartments.

Intravenous delivery of a multi-mechanistic cancer-targeted oncolytic poxvirus in humans

The efficacy and safety of biological molecules in cancer therapy, such as peptides and small interfering RNAs (siRNAs), could be markedly increased if high concentrations could be achieved and amplified selectively in tumour tissues versus normal tissues after intravenous administration. This has not been achievable so far in humans. We hypothesized that a poxvirus, which evolved for blood-borne systemic spread in mammals, could be engineered for cancer-selective replication and used as a vehicle for the intravenous delivery and expression of transgenes in tumours. JX-594 is an oncolytic poxvirus engineered for replication, transgene expression and amplification in cancer cells harbouring activation of the epidermal growth factor receptor (EGFR)/Ras pathway, followed by cell lysis and anticancer immunity. Here we show in a clinical trial that JX-594 selectively infects, replicates and expresses transgene products in cancer tissue after intravenous infusion, in a dose-related fashion. Normal tissues were not affected clinically. This platform technology opens up the possibility of multifunctional products that selectively express high concentrations of several complementary therapeutic and imaging molecules in metastatic solid tumours in humans.

Mapatumumab, an Antibody Targeting TRAIL-R1, in Combination With Paclitaxel and Carboplatin in Patients With Advanced Solid Malignancies: Results of a Phase I and Pharmacokinetic Study

PURPOSE A phase I study assessed the safety, tolerability, pharmacokinetics, and preliminary antitumor effect of mapatumumab, a fully-human agonist monoclonal antibody to the tumor necrosis factor-related apoptosis-inducing ligand receptor 1 (TRAIL-R1, DR4), in combination with paclitaxel and carboplatin. PATIENTS AND METHODS Patients with advanced solid malignancies received 3, 10, or 20 mg/kg of mapatumumab with standard doses of paclitaxel and carboplatin every 21 days for up to six cycles in the absence of disease progression. Additional cycles of paclitaxel and/or mapatumumab were permissible in selected cases. RESULTS Twenty-seven patients (21 males), with a median age of 54 years, received mapatumumab in the following three cohorts: 3 mg/kg (n = 4), 10 mg/kg (n = 11), and 20 mg/kg (n = 12). The median number of cycles was four. Dose-limiting toxicities (DLTs) were grade 3 hypersensitivity reaction (n = 1) and neutropenic fever (n = 1), both at 10 mg/kg. Non-DLT treatment-related adverse events occurring in more than 10% of administered doses included alopecia, neutropenia, fatigue, nausea, anemia, thrombocytopenia, anorexia, and neuropathy. Paclitaxel and carboplatin exposures were similar in the presence or absence of mapatumumab. Plasma mapatumumab concentrations seemed similar to data from previous phase I monotherapy studies. Five patients (19%) achieved a confirmed radiologic partial response (including one pathologic complete response), and 12 patients (44%) had stable disease as their best response. CONCLUSION Mapatumumab is well-tolerated up to 20 mg/kg in combination with paclitaxel and carboplatin. There are no apparent pharmacokinetic interactions among the drugs. Preliminary anticancer activity demonstrated clinical benefit for the majority of these patients.

Antitumor activity and safety of pembrolizumab in patients (pts) with advanced squamous cell carcinoma of the head and neck (SCCHN): Preliminary results from KEYNOTE-012 expansion cohort.

LBA6008 Background: Pembrolizumab (MK-3475) is a humanized monoclonal antibody that blocks interaction of PD-1 with its ligands, PD-L1 and PD-L2, thereby promoting activity of tumor-specific effector T cells. KEYNOTE 012 (NCT01848834) had previously demonstrated clinical activity of pembrolizumab 10 mg/kg every 2 weeks in patients (pts) with recurrent/metastatic SCCHN enriched for PD-L1-positive tumors with a response rate of 20%. We now report on the larger SCCHN expansion cohort of KEYNOTE 012, irrespective of biomarker status using a 3-weekly fixed dose. METHODS Pts with advanced SCCHN irrespective of PD-L1 expression or HPV status received a fixed dose of 200 mg pembrolizumab, intravenously, every 3 weeks. Pts were evaluated every 8 weeks with radiographic imaging. The primary end point was overall response rate (ORR) per investigator assessment (RECIST 1.1). Secondary objectives included progression-free survival (PFS) and overall survival (OS). Adverse events (AEs) were assessed according to CTCAE v4. PD-L1 was assessed retrospectively by immunohistochemistry. RESULTS 132 pts with recurrent/metastatic SCCHN were enrolled. Mean (SD) age was 58.9 (9.7) years; 83.3% were male; 56.8% had ≥ 2 lines of therapy for recurrent disease. 73/132 pts (55.3%) remain on treatment. Out of 132 treated pts, 99 pts were available for this preliminary efficacy analysis with a post-baseline scan or discontinued therapy prior to the scan due to clinical progression or AE. ORR (confirmed and unconfirmed) per RECIST 1.1 was 18.2% (95% CI, 11.1-27.2) with 18 partial responses and 31.3% with stable disease. Biomarker analysis is ongoing and results will be presented. Drug-related AEs of any grade occurred in 47% of all enrolled pts, and drug-related grade ≥ 3 AEs occurred in 7.6%. The most common drug-related AEs ( ≥ 5%) of any grade were fatigue (12.1%), decreased appetite (6.8%), pyrexia (6.1%), and rash (5.3%). CONCLUSIONS Pembrolizumab given at a fixed dose of 200 mg every 3 weeks was well tolerated and demonstrated a clinically meaningful ORR of 18.2% in pts with recurrent/metastatic SCCHN. CLINICAL TRIAL INFORMATION NCT01848834.

Phase III, randomized trial (CheckMate 057) of nivolumab (NIVO) versus docetaxel (DOC) in advanced non-squamous cell (non-SQ) non-small cell lung cancer (NSCLC).

LBA109 Background: Options for advanced non-SQ NSCLC patients (pts) who progress after platinum-based doublet chemotherapy (PT-DC) are limited, with minimal improvement in overall survival (OS). We report results from a randomized, global phase III study of NIVO, a fully human IgG4 programmed death-1 (PD-1) immune checkpoint inhibitor antibody, vs DOC in pts with advanced non-SQ NSCLC after failure of PT-DC and tyrosine kinase inhibitor, if eligible. METHODS Pts were randomized to NIVO 3 mg/kg Q2W (n=292) or DOC 75 mg/m2 Q3W (n=290) until progression or discontinuation due to toxicity/other reasons. Primary objective was OS; Secondary objectives were investigator-assessed objective response rate (ORR; per RECIST v1.1), progression-free survival (PFS), efficacy by PD-L1 expression, quality of life, and safety. RESULTS NIVO demonstrated superior OS (HR=0.73; 96% CI: 0.59, 0.89; P=0.00155) and improved ORR (19.2% vs 12.4%; P=0.0235). HR for PFS was 0.92 (95% CI: 0.77, 1.11; P=0.393). PD-L1 expression was associated with benefit from NIVO (Table). In PD-L1+ pts, NIVO showed improved efficacy across all endpoints at predefined 1%, 5%, and 10% cut- points. Grade 3-5 drug-related AEs occurred in 10.5% (30/287) of NIVO and 53.7% (144/268) of DOC pts. No deaths were related to NIVO vs 1 DOC-related death. After discontinuation, 42.1% of NIVO and 49.7% of DOC pts received subsequent systemic therapy. CONCLUSIONS NIVO demonstrated superior OS vs DOC in pts with advanced non-SQ NSCLC after failure of PT-DC. The safety profile of NIVO 3 mg/kg Q2W was favorable vs DOC. NIVO demonstrated survival benefit across histologies in two randomized phase III trials. CLINICAL TRIAL INFORMATION NCT01673867. [Table: see text].

Systemic therapy of brain metastases: non-small cell lung cancer, breast cancer, and melanoma.

Brain metastases (BM) occur frequently in many cancers, particularly non-small cell lung cancer (NSCLC), breast cancer, and melanoma. The development of BM is associated with poor prognosis and has an adverse impact on survival and quality of life. Commonly used therapies for BM such as surgery or radiotherapy are associated with only modest benefits. However, recent advances in systemic therapy of many cancers have generated considerable interest in exploration of those therapies for treatment of intracranial metastases.This review discusses the epidemiology of BM from the aforementioned primary tumors and the challenges of using systemic therapies for metastatic disease located within the central nervous system. Cumulative data from several retrospective and small prospective studies suggest that molecularly targeted systemic therapies may be an effective option for the treatment of BM from NSCLC, breast cancer, and melanoma, either as monotherapy or in conjunction with other therapies. Larger prospective studies are warranted to further characterize the efficacy and safety profiles of these targeted agents for the treatment of BM.

BLP-25 liposomal vaccine: a promising potential therapy in non-small-cell lung cancer

Despite marginal improvements in survival gained from multimodality treatment, long-term survival rates remain low for lung cancer, which remains the leading cause of cancer-related mortality in North America. BLP25 liposomal (L-BLP25) vaccine (Stimuvax™) is a promising liposomal vaccine designed to generate an immune response against MUC1, a glycoprotein expressed on the cell surface of many normal epithelial tissues and over or aberrantly expressed on many carcinoma cells, including non-small-cell lung cancer (NSCLC). MUC1 is potentially a good target for immunotherapy, as evidenced by preclinical data and in Phase I and II clinical trials demonstrating the potential early activity of L-BLP25 with minimal toxicity in NSCLC. A Phase III randomized, placebo-controlled trial of L-BLP25 is currently being conducted in stage III NSCLC patients.

Autologous transplantation for primary systemic AL amyloidosis is feasible outside a major amyloidosis referral centre: the Calgary BMT Program experience.

Summary:Recent reports from large amyloidosis referral centers suggest that primary systemic AL amyloidosis patients treated with high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT) survive longer than historical controls treated with less intensive chemotherapy, despite high transplant-related mortality (TRM) rates of >10%. A retrospective review was conducted to determine if the outcome of ASCT for AL amyloidosis at our institution was similar to that reported at major amyloidosis referral centers. Over a 7 year period, we treated a total of 15 AL amyloidosis patients with ASCT, including four with poor prognosis cardiac or multisystem involvement. No TRM was observed. Overall, 10 patients (67%) achieved a complete hematological response and four patients (27%) achieved a complete organ response. The 4-year event-free and overall survival rates were 60% (95% CI 32–89%) and 75% (95% CI 50–100%), respectively. One patient, who presented with cardiac failure and multiorgan involvement with colonic bleeding currently remains in complete remission 62 months post-ASCT. In conclusion, ASCT for primary AL amyloidosis can safely be performed at experienced transplant centers that are not associated with major amyloidosis referral centers, and is feasible for patients who have multisystem involvement, particularly for motivated patients with good performance status.

Analysis of human equilibrative nucleoside transporter 1 (hENT1) protein in non-Hodgkin's lymphoma by immunohistochemistry

The human equilibrative nucleoside transporter 1 (hENT1) is a member of the equilibrative nucleoside transporter family that mediates cellular entry of gemcitabine, cytarabine, and fludarabine. Deficiency in hENT1 confers resistance to toxicity of these drugs in a variety of model systems. Since some nucleoside analogs have a role in treating patients with non-Hodgkins lymphoma (NHL), this study was undertaken to assess hENT1 abundance in NHL. A total of 115 cases of NHL of various subtypes and 15 reactive lymph nodes were evaluated for the presence of hENT1 protein using immunohistochemistry applied to frozen tissues. Samples were considered positive when ≥50% of neoplastic cells showed immunostaining. In reactive lymph nodes, hENT1 was confined to the germinal centers, whereas mantle zone B-cells and interfollicular T-cells were negative. In NHL, a relatively high frequency of hENT1 positivity was found in Burkitt lymphoma/leukemia (63%), diffuse large B-cell lymphoma (DLCL; 45%), and follicular lymphoma (40%). In DLCL, 26% of cases were positive for CD10, and CD10-positive DLCL cases were more likely to be hENT1 positive than CD10-negative cases (P=0.025). A lower frequency of hENT1 positivity was found in mantle cell lymphoma (13%) and peripheral T-cell lymphomas (37%). All marginal zone lymphomas (n=5), chronic lymphocytic leukemia small lymphocytic lymphomas (n=10), plasmacytoma (n=3), acute lymphoblastic lymphoma/leukemia, and anaplastic large-cell lymphomas (n=5) were negative. In conclusion, hENT1 was most frequently found in benign and malignant follicular center cells. Prospective studies to assess the value of hENT1 immunostaining in predicting resistance to nucleoside chemotherapy for NHL are warranted.

Adjuvant Radiotherapy for Stages II and III Resected Thymoma: A Single-institutional Experience.

Introduction:The role of adjuvant radiation for Masaoka stages II and III thymoma remains controversial. The aim of this study was to evaluate the clinical benefit of radiation therapy for resected stages II and III thymoma patients. Methods:We retrospectively reviewed the medical records of 175 thymoma patients treated from July 1996 to January 2013 at University of Washington Medical Center; 88 patients with adequate follow-up and who met histologic criteria were included. We evaluated progression-free survival (PFS) and overall survival (OS), and compared these outcomes in patients treated by surgery (S) alone versus surgery plus radiotherapy (S+RT). Cox regression models and log-rank tests were used to compare PFS and OS for S versus S+RT, and they were further assessed by margin-positive versus margin-negative subgroups using Kaplan-Meier curves. Results:Among the 88 thymoma patients, 22 were stage II and 18 were stage III. For all stages II and III patients, adjuvant radiation was not identified as a significant predictor for PFS (P=0.95) or OS (P=0.63). A positive surgical margin predicted for a worse OS (hazard ratio=7.1; P=0.004). Further investigation revealed for resection margin-positive patients; S+RT had higher OS than S alone (P=0.006). Conclusions:For stages II and III thymoma, postoperative adjuvant radiation was not associated with statistically significant differences in PFS or OS in this study. Our results indicated a potential OS benefit of adjuvant RT in patients with positive resection margins, and therefore may be considered in this patient population.