Frank A. Scappaticci

Mechanisms and Future Directions for Angiogenesis-Based Cancer Therapies

Targeting angiogenesis represents a new strategy for the development of anticancer therapies. New targets derived from proliferating endothelial cells may be useful in developing anticancer drugs that prolong or stabilize the progression of tumors with minimal systemic toxicities. These drugs may also be used as novel imaging and radiommunotherapeutic agents in cancer therapy. In this review, the mechanisms and control of angiogenesis are discussed. Genetic and proteomic approaches to defining new potential targets on tumor vasculature are then summarized, followed by discussion of possible antiangiogenic treatments that may be derived from these targets and current clinical trials. Such strategies involve the use of endogenous antiangiogenic agents, chemotherapy, gene therapy, antiangiogenic radioligands, immunotherapy, and endothelial cell-based therapies. The potential biologic end points, toxicities, and resistance mechanisms to antiangiogenic agents must be considered as these therapies enter clinical trials.

Randomized Phase II Study of Bevacizumab in Combination With Chemotherapy in Previously Untreated Extensive-Stage Small-Cell Lung Cancer: Results From the SALUTE Trial

PURPOSE Because of promising efficacy signals in single-arm studies, a placebo-controlled, double-blind, randomized phase II trial was designed to assess the efficacy and safety of adding bevacizumab to first-line standard chemotherapy for treatment of extensive-stage small-cell lung cancer (SCLC). PATIENTS AND METHODS Patients with SCLC were randomly assigned to receive bevacizumab or placebo, with cisplatin or carboplatin plus etoposide, for four cycles followed by single-agent bevacizumab or placebo until progression or unacceptable toxicity. The primary end point was progression-free survival (PFS). RESULTS Fifty-two patients were randomly assigned to the bevacizumab group and 50 to the placebo group; 69% versus 66%, respectively, completed four cycles of therapy. Median PFS was higher in the bevacizumab group (5.5 months) than in the placebo group (4.4 months; hazard ratio [HR], 0.53; 95% CI, 0.32 to 0.86). Median overall survival (OS) was similar for both groups (9.4 v 10.9 months for bevacizumab and placebo groups, respectively), with an HR of 1.16 (95% CI, 0.66 to 2.04). Overall response rates were 58% (95% CI, 43% to 71%) for the bevacizumab group and 48% (95% CI, 34% to 62%) for the placebo group. Median duration of response was 4.7 months for the bevacizumab group and 3.2 months for the placebo group. In the bevacizumab and placebo groups, 75% versus 60% of patients, respectively, experienced one or more grade 3 or higher adverse events. No new or unexpected safety signals for bevacizumab were observed. CONCLUSION The addition of bevacizumab to cisplatin or carboplatin plus etoposide for treatment of extensive-stage SCLC improved PFS, with an acceptable toxicity profile. However, no improvement in OS was observed.

Phase 2 trial of linifanib (ABT-869) in patients with unresectable or metastatic hepatocellular carcinoma

The efficacy and safety of linifanib (ABT‐869), a selective inhibitor of vascular endothelial growth factor and platelet‐derived growth factor receptor tyrosine kinases, were assessed in this phase 2, single‐arm, open‐label, multicenter trial.

Phase 2 Trial of Linifanib (ABT-869) in Patients with Advanced Non-small Cell Lung Cancer

Introduction: This study assessed activity and safety of linifanib (ABT-869), a selective inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptors, in patients with locally advanced or metastatic non-small cell lung cancer. Methods: In this open-label trial (NCT00517790), patients who received one to two prior lines of systemic therapy were randomized to oral linifanib 0.10 mg/kg (low dose) or 0.25 mg/kg (high dose) once daily. Tumor responses were assessed by independent central imaging review every 8 weeks. The primary end point was progression-free rate at 16 weeks. Secondary end points included objective response rate, time to progression, progression-free survival, and overall survival. Safety was also assessed. Results: Between August 2007 and October 2008, 139 patients were enrolled; 60% had two or more prior regimens, and 88% had nonsquamous cell carcinoma. The objective response rate (low dose and high dose) was 5.0% (3.1 and 6.8%), progression-free rate at 16 weeks was 33.1% (32.3 and 33.8%), median time to progression was 3.6 months (3.6 and 3.7 months), median progression-free survival was 3.6 months (3.5 and 3.6 months), and median overall survival was 9.0 months (10.0 and 8.3 months). The most common linifanib-related adverse events were fatigue (42%), decreased appetite (38%), hypertension (37%), diarrhea (32%), nausea (27%), palmar-plantar erythrodysesthesia (24%), and proteinuria (22%). These events were more common in the high-dose group. The most common linifanib-related grade 3 or 4 adverse event was hypertension (14%). Conclusions: Linifanib is active in advanced non-small cell lung cancer as second- or third-line therapy. Increased adverse event rates were observed at the high dose of linifanib.

Safety and Efficacy of Combining Sunitinib with Bevacizumab + Paclitaxel/Carboplatin in Non-small Cell Lung Cancer

Introduction: Bevacizumab (B) improves survival of patients with metastatic, nonsquamous non-small cell lung cancer. Based on encouraging results from preclinical studies combining B with sunitinib (S), a phase II, randomized, open-label study (Study Assessing the Blockade of both VEGF Receptor and ligand to enhance Efficacy in Lung) was initiated to assess clinical outcomes of adding S to paclitaxel (P)/carboplatin (C) + B (PCB) for first-line treatment of locally advanced, metastatic, or recurrent nonsquamous non-small cell lung cancer. Methods: Study enrollment was to occur in three phases. In the first phase, patients received PC + B (15 mg/kg every 3 weeks), ±S (25 mg daily, 2 weeks on, 1 week off). If tolerated, the second phase would include a third cohort receiving 37.5 mg S. The third phase would consist of PCB ± highest tolerable dose S. Results: Between March 2007 and January 2008, 26 patients were randomized to receive PCB and 30 to PCB + S 25 mg. Because of poor tolerability, none of the patients were escalated to 37.5 mg S. Median treatment duration was 10.3 weeks for PCB and 6.0 weeks for PCB + S. Thirty-five percent of patients on PCB + S required S dose reduction, 52% required S treatment interruption, and 59% discontinued S because of adverse events, most frequently hematologic events (neutropenia, thrombocytopenia, and leukopenia) and fatigue. Patients receiving PCB + S required more B interruptions (38% versus 19% for PCB) and discontinuation (52% versus 35%) because of adverse events. Survival data were limited by small sample sizes and limited treatment duration. Overall survival was not mature at time of analysis: median 6.6 months for PCB + S and not reached for PCB. Two out of 25 efficacy-evaluable patients randomized to the PCB + S cohort had confirmed partial responses, compared with 5 of 19 randomized to the PCB cohort. Conclusions: The addition of S to PCB was not well tolerated because of toxicities. This combination should not be studied further at these doses and schedules.

Phase 2 trial of linifanib (ABT-869) in patients with advanced renal cell cancer after sunitinib failure.

PURPOSE This study assessed the efficacy and safety of linifanib in patients with advanced renal cell carcinoma (RCC) who were previously treated with sunitinib. MATERIALS AND METHODS This open-label, multicentre, phase 2 trial of oral linifanib 0.25 mg/kg/day enrolled patients who had prior nephrectomy and adequate organ function. The primary end-point was objective response rate (ORR) per response evaluation criteria in solid tumors (RECIST) by central imaging. Secondary end-points were progression-free survival (PFS), overall survival (OS) and time to progression (TTP). Safety was also assessed. RESULTS Fifty-three patients, median age 61 years (range 40-80) were enrolled (August 2007 to October 2008) across 12 North-American centres. Median number of prior therapies was 2 (range 1-4); 43 patients (81%) had clear-cell histology. ORR was 13.2%, median PFS was 5.4 months (95% Confidence Interval (CI): 3.6, 6.0) and TTP was the same; median OS was 14.5 months (95% CI: 10.8, 24.1). The most common treatment-related adverse events (AEs) were diarrhoea (74%), fatigue (74%) and hypertension (66%), and the most common treatment-related Grade 3/4 AE was hypertension (40%). CONCLUSIONS Linifanib demonstrated clinically meaningful activity in patients with advanced RCC after sunitinib failure. At 0.25 mg/kg/day, significant dose modifications were required. An alternative, fixed-dosing strategy is being evaluated in other trials.

Lack of effect of bevacizumab on wound healing/bleeding complications when given 28–60 days following primary cancer surgery

3530 Background: Bevacizumab [Avastin (BV)] is a humanized monoclonal antibody directed against vascular endothelial growth factor. A recent randomized, double-blinded, Phase III trial showed that addition of Avastin to chemotherapy (bolus irinotecan, 5-FU, leucovorin -IFL) increased survival compared with IFL alone. Antiangiogenic therapy has previously shown delay in wound healing in preclinical models. Therefore, we undertook an analysis of wound healing in subjects receiving BV plus bolus IFL and BV plus 5-FU/LV versus those that received bolus IFL alone. METHODS Wound healing and bleeding complications were analyzed in subjects who underwent primary cancer surgery (i.e., colonic or rectal resection to remove tumor) within 28-60 days of starting study treatment. Sixty-day post-operative adverse events reported as abnormal healing, wound dehiscence, delayed wound healing, bowel perforation, fistula, abscess, and hemorrhage were studied. RESULTS A total of 150 subjects receiving BV plus bolus IFL and 37 subjects receiving BV plus 5-FU/LV underwent prior cancer surgery before initial use of BV plus chemotherapy compared with 155 subjects who received bolus IFL alone. The incidence of Grade 3 / 4 wound healing / bleeding in subjects was 1 subject (0.65 %) in the bolus IFL arm alone, 3 subjects (2.0 %) in the BV + bolus IFL arm, and no subjects (0 %) in the BV + 5-FU/LV arm. CONCLUSIONS These results suggest that surgery in subjects within 28-60 days before the initial use of Avastin does not lead to a significantly increased incidence of wound healing / bleeding complications. These results are encouraging for the planned evaluation of Avastin in adjuvant colorectal trials. [Table: see text].

MAVERICC, a randomized, biomarker-stratified, phase 2 study of mFOLFOX6-bevacizumab vs FOLFIRI-bevacizumab as first-line chemotherapy in metastatic colorectal cancer

Purpose: MAVERICC compared the efficacy and safety of modified leucovorin/5-fluorouracil/oxaliplatin plus bevacizumab (mFOLFOX6-BV) with leucovorin/5-fluorouracil/irinotecan plus bevacizumab (FOLFIRI-BV) in patients with previously untreated metastatic colorectal cancer (mCRC). Patients and Methods: MAVERICC was a global, randomized, open-label, phase II study. Primary objectives were to assess associations between (i) excision repair cross-complementing 1 (ERCC1) expression with progression-free survival (PFS), and (ii) plasma VEGF A (VEGF-A) with PFS in patients with previously untreated mCRC receiving mFOLFOX6-BV or FOLFIRI-BV. Before randomization, patients were stratified by tumoral ERCC1/β-actin mRNA expression level and region. Results: Of 376 enrolled patients, 188 each received mFOLFOX6-BV and FOLFIRI-BV. PFS and overall survival (OS) were comparable between FOLFIRI-BV and mFOLFOX6-BV, with numerically higher PFS [HR = 0.79; 95% CI (confidence interval): 0.61–1.01; P = 0.06] and OS (HR = 0.76; 95% CI: 0.56–1.04; P = 0.09) observed for FOLFIRI-BV. In the high ERCC1 subgroup, PFS and OS were comparable between treatment groups (PFS, HR = 0.84; 95% CI: 0.56–1.26; P = 0.40; OS, HR = 0.80; 95% CI: 0.51–1.26; P = 0.33). Across treatment groups, high plasma VEGF-A levels (>5.1 pg/mL) were observed with shorter PFS (HR = 1.19; 95% CI: 0.93–1.53; P = 0.17) and significantly shorter OS (HR = 1.64; 95% CI: 1.20–2.24; P < 0.01) versus low levels (≤5.1 pg/mL). Safety findings for FOLFIRI-BV or mFOLFOX6-BV were comparable with those reported previously. Conclusions: First-line FOLFIRI-BV and mFOLFOX6-BV had comparable PFS and OS, similar to results in patients with high baseline tumor ERCC1 levels. There were no new safety signals with these bevacizumab-containing regimens.

Targeting the VEGF/VEGFR Axis for Cancer Therapy

Promising new antiangiogenic strategies are emerging for the treatment of cancer. Numerous candidate drugs that target vascular endothelial growth factor (VEGF), VEGF receptors (VEGFR), integrins, matrix metalloproteinases, and other blood vessel targets are being developed and tested in clinical trials. Many approaches have been taken to interfere or completely block angiogenesis. These include antibodies, small molecules, gene therapy, vaccine strategies, and antiangiogenic radioligands. New insight has been gained from completed phase III trials with antiangiogenic drugs, including trial design, dosing, toxicities, and resistance. This chapter will focus on the VEGF/VEGFR axis and the clinical trial results of interfering with this axis by the VEGF-targeting agent Avastin™ (bevacizumab, rhuMAb VEGF).