Tyrosine Kinase Inhibitors and Acute Pancreatitis

Abstract

In 2007, Badalov et al. [1] revised the data in the literature on drug-induced acute pancreatitis on the basis of a new classification system; they suggested the following classification: Class Ia drugs having at least one case report with positive rechallenge, excluding all other causes, such as alcohol, hypertriglyceridemia, gallstones and other drugs; Class Ib those drugs having at least one case report with positive rechallenge in whom other causes, such as alcohol, hypertriglyceridemia, gallstones and other drugs were not ruled out; Class II those drugs with at least four cases in the literature and consistent latency (75% of cases or more); Class III drugs with at least two cases in the literature, no consistent latency among cases and no rechallenge and, finally, Class IV the drugs not fitting into the above-mentioned classes, having a single case report published in the medical literature, without rechallenge. The advent of new drugs can rapidly increase the number of substances causing acute pancreatitis. One example is the family of the drugs called “tyrosine kinase inhibitors” which are drugs used for gastrointestinal stromal tumors (imatinib and sunitinib), unresectable hepatocellular carcinomas (sorafenib) and advanced renal cell carcinomas (sorafenib and sunitinib). These drugs are capable of inhibiting VEGF receptors 2 and 3, the platelet-derived growth factor receptor, fms-related tyrosine kinase 3 (FLT3), c-Kit and ret proto-oncogene (RET) [2]. In addition, they inhibit the breakpoint cluster regionAbelson proto-oncogene (BCR-ABL) chimeric protein which is thought to play a central role in the pathogenesis of Philadelphia (Ph) chromosomepositive leukemias, notably chronic myeloid leukemia [3]. Imatinib mesylate represented a major therapeutic advance over conventional chronic myeloid leukemia therapy, with more than 90% of patients obtaining complete hematologic response and 70-80% of patients achieving a complete cytogenetic response. Resistance to imatinib represents a clinical challenge and is often the result of point mutations causing a conformation change in BCR-ABL which impairs imatinib binding. Novel targeted agents designed to overcome imatinib resistance include dasatinib, nilotinib, bosutinib and others [4]. One of the adverse effects of all these drugs is the increase in serum amylase and/or lipase levels [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17], sometimes with very high serum activity levels evaluated according to the Common Terminology Criteria for Adverse Events Version 3.0 (Table 1) [18]. The frequency of the increase in amylase and lipase was high in patients treated with sorafenib and was low for those treated with nilotinib. There are several hypotheses regarding the increase of serum pancreatic enzyme activities and they especially regard nilotinib: 1) nilotinib is able to inhibit the nonreceptor tyrosine kinase c-abl with high affinity; other than the kinase domain, the c-abl protein interacts with signaling proteins, nucleo-cytoplasmic shuttling, DNA and actin binding sites, thus integrating information from multiple pathways in various cellular compartments. Therefore, it is possible that c-abl inhibition might interfere with the molecular mechanisms regulating pancreatic cell death, inducing pancreatic damage; 2) nilotinib may also act on unknown intracellular pathways involved in calcium release from the intracellular acinar stores, which regulate exocrine pancreatic secretion, or may promote the accumulation of fatty acid inside the pancreatic acinar cells, which disturbs exocytosis; however, we should also point out that an increase in the serum concentration of pancreatic enzymes may be an expression of pancreatic involvement during the diseases studied or that elevated amylase and/or lipase levels may also be a non-specific phenomenon without any clinical implication.