sjg-136 and Colonic-Neoplasms

SJG-136 is a pyrrolobenzodiazepine dimer that forms DNA crosslinks and has demonstrated broad antitumor activity. We undertook this trial to determine the maximum-tolerated dose (MTD), toxicities and pharmacokinetic (PK) profile of SJG-136 in patients with an advanced solid tumor.. In this phase I study, patients were treated with SJG-136 on days 1, 8 and 15 of a 28-day cycle. Dose levels studied were 10, 20, 40 and 60 microg/m2. PK parameters of SJG-136 were assessed following the intravenous administration of SJG-136 on days 1 and 15 of cycle 1.. Twenty-one patients with advanced solid tumors were treated. Patients had a median of two prior chemotherapy regimens. Fatigue was dose-limiting with SJG-136 60 microg/m2/day administered on days 1, 8 and 15 of a 28-day cycle. Grade 3 thrombocytopenia and delayed onset liver toxicity were seen in one patient each. PK parameters of SJG-136 indicated dose-proportional increases in systemic exposure with increasing doses. No objective responses were seen.. For patients with advanced solid tumors, the MTD of SJG-136 is 40 microg/m2/day administered on days 1, 8 and 15 of a 28-day cycle. The major dose limiting toxicity was fatigue. Alternative dosing strategies are now being evaluated.

Topics: Aged; Antineoplastic Agents; Benzodiazepinones; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Tolerance; Female; Humans; Lung Neoplasms; Male; Maximum Tolerated Dose; Melanoma; Middle Aged; Ovarian Neoplasms; Pyrroles; Urinary Bladder Neoplasms

SJG-136 is a novel pyrrolobenzodiazepine dimer analogue that acts as a minor-groove interstrand DNA cross-linking agent. The present study investigated the impact of ABCB1 (mdr-1) expression on the activity of SJG-136 using both in vitro and in vivo systems. SJG-136 was highly potent in the colon cancer cell lines HCT-116, HT-29 and SW620 (IC50 0.1-0.3 nM). However, HCT-8 and HCT-15 cells expressing significant levels of mdr-1 were less sensitive (IC50 2.3 and 3.7 nM, respectively) using a SRB assay. The cytotoxicity was increased in HCT-15 and A2780(AD) in presence of 5 microg/ml verapamil. Mdr-1 mRNA expression was determined by qRT-PCR and correlated to SJG-136 IC50s (r2=0.86, P=0.0001). Isogenic 3T3 cells expressing mdr-1 cDNA (3T3 pHamdr-1) were less sensitive to SJG-136 than the parental 3T3 cells (IC50 208 and 6.3 nM, respectively). Finally, SJG-136 (120 microg/kg/d dx5) was highly active against A2780 xenografts (SGD=275) but not A2780(AD) xenografts (SGD=67).

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Benzodiazepinones; Cell Line, Tumor; Colonic Neoplasms; Drug Combinations; Humans; Immunoblotting; Inhibitory Concentration 50; Mice; Mice, Inbred C57BL; Pyrroles; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transplantation, Heterologous; Verapamil