The study consists of 2 phases. In part 1 (potential dose de-escalation phase) subjects will be enrolled at a fixed dose of CMC544. In case of occurrence of dose limiting toxicity (DLT), cohorts of 3 to 6 subjects will evaluate a de-escalating dose of CMC544 in combination with set doses of rituximab, gemcitabine and oxaliplatin in order to obtain the MTD or recommended dose of CMC544 in this regimen. In part 2 (dose expansion phase) further safety and preliminary efficacy data of the proposed combination will be analyzed.