cbp-501 and Lung-Neoplasms

CBP501, a synthetic duodecapeptide, increases cisplatin influx into tumor cells through an interaction with calmodulin enhancing cisplatin cytotoxicity, and effects cell cycle progression by abrogating DNA repair at the G2 checkpoint. In phase I clinical trials of CBP501 alone or in combination with cisplatin, the most common toxicity was infusion-related urticaria. Activity of CBP501 plus cisplatin was observed in patients with ovarian cancer and mesothelioma, including some patients previously treated with cisplatin.. Chemotherapy naïve patients with unresectable MPM were stratified by histology and performance status, and randomized 2:1 to pemetrexed/cisplatin plus CBP501 25mg/m(2) IV (Arm A) or pemetrexed/cisplatin alone (Arm B). The primary endpoint was progression free survival (PFS) at 4 months.. 65 patients were randomized, and 63 were treated. Patient characteristics in the two arms were balanced. Based on independent radiology review of the treated population, 25/40 patients (63%) in Arm A and 9/23 (39%) in Arm B had PFS≥4mo; the median PFS was 5.1mo (95% CI, 3.9, 6.5) vs 3.4mo (2.5, 6.7). Median OS was 13.3mo (9.2, 16.3) in Arm A and 12.8 (6.5, 16.1) in Arm B. Adverse events were not different than expected from standard chemotherapy, and comparable in the two arms, aside from infusion reactions which occurred in 70% of patients treated with CBP501.. While this randomized phase II trial met its primary endpoint of PFS at 4 months, other parameters such as response rate and overall survival suggest that the addition of CBP501 does not improve the efficacy of standard chemotherapy for MPM.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; cdc25 Phosphatases; Cisplatin; Female; Glutamates; Guanine; Humans; Lung Neoplasms; Male; Mesothelioma; Mesothelioma, Malignant; Middle Aged; Neoplasm Staging; Pemetrexed; Peptide Fragments; Treatment Outcome

CBP501 is an anticancer drug candidate that was investigated in two randomized phase II clinical trials for patients with nonsquamous non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma (MPM). CBP501 has been shown to have two mechanisms of action, namely calmodulin modulation and G2 checkpoint abrogation. Here, we searched for a biomarker to predict sensitivity to CBP501. Twenty-eight NSCLC cell lines were classified into two subgroups, CBP501-sensitive and -insensitive, by quantitatively analyzing the cis-diamminedichloro-platinum (II) (CDDP)-enhancing activity of CBP501 through treatments with short-term (1 hour) coexposure to CDDP and CBP501 or to either alone. Microarray analysis was performed on these cell lines to identify gene expression patterns that correlated with CBP501 sensitivity. We found that multiple nuclear factor erythroid-2-related factor 2 (Nrf2) target genes showed high expression in CBP501-insensitive cell lines. Western blot and immunocytochemical analysis for Nrf2 in NSCLC cell lines also indicated higher protein level in CBP501-insensitive cell lines. Moreover, CBP501 sensitivity is modulated by silencing or sulforaphane-induced overexpression of Nrf2. These results indicate that Nrf2 transcription factor is a potential candidate as a biomarker for resistance to CBP501. This study might help to identify those subpopulations of patients who would respond well to the CBP501 and CDDP combination treatment of NSCLC.

Topics: Biomarkers, Tumor; Calmodulin; Carcinoma, Non-Small-Cell Lung; cdc25 Phosphatases; Cell Cycle; Cell Line, Tumor; Drug Resistance, Neoplasm; G2 Phase; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Lentivirus; Lung Neoplasms; Microscopy, Fluorescence; NF-E2-Related Factor 2; Oligonucleotide Array Sequence Analysis; Peptide Fragments; RNA, Messenger; RNA, Small Interfering