Regorafenib in metastatic colorectal cancer: more data for clinical decisions

Regorafenib is a multiple kinase inhibitor. It influences/blocks angiogenesis (VEGFR1-3, TIE2), proliferation (KIT, RET, RAF-1, BRAF), metastatic activity (VEGFR2-3, PDGFR), tumor immunogenicity (CSF1R), tumor microenvironment (PDGFR-, PDGFR-, FGFR1-2). Regorafenib has several indications including metastatic colorectal cancer. Efficacy and safety of regorafenib data from clinical trials (CORRECT, CONCUR, CONSIGN) and observational trials from real world (REBECCA, CORRELATE, RECORA, PMS, REGOTAS) are summarized and presented in this issue. State of the matter of molecular-biologic predictors (KRAS, PIK3CA ANG-2, VEGF-A, LDH, CCL5/CCR5, CA 19-9) and radiological predictors (RadioCORRECT and other trials) is highlighted. Regimens with dose modification and its influence on effectiveness and tolerability of regorafenib are described according to the data from ReDOS, RESET, REARRANGE trials. The results from retrospective trials comparing regorafenib and another approved for refractory metastatic colorectal cancer drug trifluridine/tipiracil are presented.

Development of New Meridianin/Leucettine-Derived Hybrid Small Molecules as Nanomolar Multi-Kinase Inhibitors with Antitumor Activity

Although the sea ecosystem offers a broad range of bioactivities including anticancer, none of the FDA-approved antiproliferative protein kinase inhibitors are derived from a marine source. In a step to develop new marine-inspired potent kinase inhibitors with antiproliferative activities, a new series of hybrid small molecules (5a–5g) was designed and synthesized based on chemical moieties derived from two marine natural products (Meridianin E and Leucettamine B). Over a panel of 14 cancer-related kinases, a single dose of 10 µM of the parent hybrid 5a possessing the benzo[d][1,3]dioxole moiety of Leucettamine B was able to inhibit the activity of FMS, LCK, LYN, and DAPK1 kinases with 82.5 ± 0.6, 81.4 ± 0.6, 75.2 ± 0.0, and 55 ± 1.1%, respectively. Further optimization revealed the most potent multiple kinase inhibitor of this new series (5g) with IC50 values of 110, 87.7, and 169 nM against FMS, LCK, and LYN kinases, respectively. Compared to imatinib (FDA-approved multiple kinase inhibitor), compound 5g was found to be ~ 9- and 2-fold more potent than imatinib over both FMS and LCK kinases, respectively. In silico docking simulation models of the synthesized compounds within the active site of FMS, LCK, LYN, and DAPK1 kinases offered reasonable explanations of the elicited biological activities. In an in vitro anticancer assay using a library of 60 cancer cell lines that include blood, lung, colon, CNS, skin, ovarian, renal, prostate, and breast cancers, it was found that compound 5g was able to suppress 60 and 70% of tumor growth in leukemia SR and renal RXF 393 cell lines, respectively. Moreover, an ADME study indicated a suitable profile of compound 5g concerning cell permeability and blood-brain barrier (BBB) impermeability, avoiding possible CNS side effects. Accordingly, compound 5g is reported as a potential lead towards novel antiproliferative marine-derived kinase modulators.