Fernández, Cristian

7029 Background: CBP501, a synthetic duodecapeptide, enhances the cytotoxicity of cisplatin in cell lines and xenografts, including NCI-H226 human mesothelioma. CBP501 increases cisplatin influx into tumor cells through an interaction with calmodulin, and inhibits cell cycle progression by abrogating DNA repair at the G2 checkpoint. Phase I clinical trials combining CBP501 with cisplatin alone or with pemetrexed showed acceptable safety profiles and suggested activity. The most common toxicity of CBP501 is infusion-related urticaria, which is easily managed with diphenhydramine. Methods: Chemotherapy-naive patients with unresectable MPM were stratified by histology (epithelioid vs other) and performance status (PS 0-1 vs 2) and randomized 2:1 to Arm A: pemetrexed/cisplatin plus CBP501 25 mg/m2 IV (42 pts planned), or Arm B: pemetrexed/cisplatin alone at standard doses (21 pts planned). Patients continued on treatment until progression or intolerance; no maintenance therapy was delivered. The primary endpoint is progression free survival (PFS) in Arm A; if > 23 of the 42 patients remain free of progression more than 4 months, the combination will be deemed worthy of further study. In addition to standard CT imaging to assess response and PFS, PET scans, pulmonary function tests, and mesothelin levels were performed. Results: Enrollment was completed in October 2011. 65 pts from 14 institutions were randomized, and 63 were treated. Patient characteristics in the two arms were similar and as follows: median age 65, 82% male, 71% epithelioid histology, 8% PS2. Grade 3/4 treatment-related toxicities were uncommon, no different than expected from standard chemotherapy, and comparable in the two arms. 70% of patients treated with CBP501 had infusion reactions, all grade 1-2. The best overall response rate in evaluable patients (modified RECIST, investigator assessed) was 12/37 (32%) (95% CI 18-50) in Arm A, and 3/22 (14%) (95% CI 3-35) in Arm B. The median number of chemotherapy cycles was 5.5 in Arm A, 5 in Arm B. Conclusions: Data on the primary endpoint of PFS in Arm A are maturing and will be presented at the meeting.

Purpose To compare the progression-free survival (PFS) using a treatment regimen selected by molecular profiling (MP) of a patient's tumor with the PFS for the most recent regimen on which the patient had experienced progression (ie, patient as his own control). Patients and Methods Patients with refractory metastatic cancer had tissue samples submitted for MP in two formats including formalin-fixed tissue for immunohistochemistry and fluorescent in situ hybridization assays and immediately frozen tissue for oligonucleotide microarray (MA) gene expression assays (all performed in a Clinical Laboratory Improvement Amendments [ CLIA ] –certified laboratory). The MP approach was deemed of clinical benefit for the individual patient who had a PFS ratio (PFS on MP-selected therapy/PFS on prior therapy) of ≥ 1.3. Results In 86 patients who had MP attempted, there was a molecular target detected in 84 (98%). Sixty-six of the 84 patients were treated according to MP results. Eighteen (27%) of 66 patients had a PFS ratio of ≥ 1.3 (95% CI, 17% to 38%; one-sided, one-sample P = .007). Therefore, the null hypothesis (that ≤ 15% of this patient population would have a PFS ratio of ≥ 1.3) was rejected. Conclusion It is possible to identify molecular targets in patients' tumors from nine different centers across the United States. In 27% of patients, the MP approach resulted in a longer PFS on an MP-suggested regimen than on the regimen on which the patient had just experienced progression. Issues to be considered in interpretation of this study include limited prior experience with patients as their own controls as a study end point and overall patient attrition.