Jackman DM, Kindler HL, Yeap BY, Fidias P, Salgia R, Lucca J, Morse LK, Ostler PA, Johnson BE, Jänne PA.

Dana‐Farber Cancer Institute, Boston, Massachusetts.

Abstract

Background: We conducted a phase 2, multicenter, open-label study of erlotinib plus bevacizumab in patients with malignant pleural mesothelioma who had previously received 1 prior chemotherapy regimen. These agents have activity in non-small cell lung cancer, but their role in mesothelioma is unclear. The primary endpoint is response rate. Secondary endpoints include time to progression, survival, and toxicity.

Methods: Eligible patients with mesothelioma who had previously received 1 chemotherapy regimen were treated with erlotinib 150 mg per os daily and bevacizumab 15 mg/kg administered intravenously on Day 1 of a 21-day cycle. Treatment continued until disease progression or development of significant toxicity. Tumor response was assessed after every 2 cycles using previously established mesothelioma response criteria from Byrne and Nowak.

Results: Twenty-four eligible patients initiated therapy with erlotinib and bevacizumab between February 2004 and October 2006. There were no complete or partial responses, although 12 patients achieved stable disease for at least 2 cycles of treatment. The median time to progression was 2.2 months (95% confidence interval [CI], 1.4 months-5.9 months). The median survival was 5.8 months (95% CI, 2.8 months-10.1 months). The most common toxicities were rash and diarrhea. There were no treatment-related deaths, intracranial bleeding, or hemoptysis.

Conclusions: The combination of erlotinib and bevacizumab was tolerated reasonably well, but there was no evidence of radiographic response. This study demonstrates the feasibility of conducting trials in mesothelioma patients who have failed first-line therapy. More therapeutic studies with effective agents are needed for these patients.

Garland LL, Rankin C, Gandara DR, Rivkin SE, Scott KM, Nagle RB, Klein-Szanto AJ, Testa JR, Altomare DA, Borden EC.

University of Arizona Cancer Center, Tucson, AZ, USA.

Abstract

Purpose:Malignant pleural mesothelioma (MPM) expresses high levels of epidermal growth factor receptor (EGFR), and preclinical studies have identified antitumor activity of EGFR tyrosine kinase inhibitors (TKIs) in MPM. We conducted a phase II trial of the EGFR TKI erlotinib in previously untreated patients with MPM.

Patients and Methods: Patients with measurable and nonmeasurable disease were treated with erlotinib 150 mg/d on days 1 through 28 of each 28-day dosing cycle. Archived patient tumors were analyzed for immunohistochemical expression of EGFR, phospho-EGFR, human epidermal growth factor receptor 2 (HER2), phospho-extracellular signal-regulated kinase (ERK), and phosphatase and tensin homolog (PTEN) and phosphorylation of members of the phosphatidylinositol 3-kinase/Akt signaling pathway.

Results: Sixty-three patients were treated on the study. EGFR was highly expressed in 75% of patient tumors, as was phospho-ERK (82%), phospho-Akt (84%), phospho-mammalian target of rapamycin (74%), and phospho-forkhead (74%). HER2 was rarely expressed, and loss of PTEN was rare. For 33 patients with measurable disease, there were no objective responses; 14 patients (42%) had stable disease, 15 patients (45%) had disease progression, and four patients had inadequate assessments to determine response. Toxicities were mainly constitutional (51%), dermatologic (82%), and GI (52%); there was one death on trial, which was related to dyspnea. Median overall survival time was 10 months; 1-year survival rate was 43%; and median progression-free survival time was 2 months.

Conclusion: Single-agent erlotinib was not effective in MPM, despite high expression of EGFR. Activation of the ERK and phosphatidylinositol 3-kinase/Akt downstream pathways are possible resistance mechanisms to EGFR TKI. The activated phosphatidylinositol 3-kinase/Akt pathway is a potential therapeutic target for MPM.

Paolo A. Zucali^{1, a} and Giuseppe Giaccone^a

^aDepartment of Medical Oncology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands

Received 18 July 2006;  accepted 19 July 2006.  Available online 20 September 2006.

Abstract

Malignant mesothelioma is an aggressive tumour, with a poor prognosis and an increasing incidence as a result of widespread exposure to asbestos. The results of the treatments available are poor. Surgery and radiotherapy have a limited role in highly selected patients and systemic therapy is the only potential treatment option for the majority of patients. Despite some definite activity of the novel antifolates such as pemetrexed and raltitrexed, the results, even in combination with platinating agents, are still modest, with a median survival of approximately one year. The better understanding of the biology of mesothelioma makes the assessment of a number of targeted agents particularly interesting. Unfortunately, the targeted agents imatinib, gefitinib, erlotinib and thalidomide have been shown to be ineffective in unselected patients. Studies with anti-angiogenesis agents are ongoing. An improvement of the knowledge of major molecular pathways involved in malignant mesothelioma is needed in order to define proper targets for the systemic treatment of this disease.

Keywords: Malignant pleural mesothelioma; Biology; Management; Pemetrexed; Targeted therapy