Imatinib dose escalation versus sunitinib as a second line treatment in KIT exon 11 mutated GIST: A retrospective analysis

none14noWe retrospectively reviewed data from 123 patients (KIT exon 11 mutated) who received sunitinib or dose-escalated imatinib as second line. All patients progressed on imatinib (400 mg/die) and received a second line treatment with imatinib (800 mg/die) or sunitinib (50 mg/die 4 weeks on/2 offor 37.5 mg/day). Deletion versus other KIT 11 mutation was recorded, correlated with clinical benefits. 64% received imatinib, 36% sunitinib. KIT exon 11 mutation was available in 94 patients. With a median follow-up of 61 months, median time to progression (TTP) in patients receiving sunitinib and imatinib was 10 (95% CI 9.7-10.9) and 5 months (95% CI 3.6-6.7) respectively (P = 0.012). No difference was found in overall survival (OS) (P = 0.883). In imatinib arm, KIT exon 11 deletions was associated with a shorter TTP (7 vs 17 months; P = 0.02), with a trend in OS (54 vs 71 months P = 0.063). No difference was found in patients treated with sunitinib (P = 0.370). A second line with sunitinib was associated with an improved TTP in KIT exon 11 mutated patients progressing on imatinib 400 mg/die. Deletions in exon 11 seemed to be correlated with worse outcome in patients receiving imatinib-based second line.openVincenzi B.; Nannini M.; Fumagalli E.; Bronte G.; Frezza A.M.; De Lisi D.; Ceruso M.S.; Santini D.; Badalamenti G.; Pantaleo M.A.; Russo A.; Dei Tos A.P.; Casali P.; Tonini G.Vincenzi, B.; Nannini, M.; Fumagalli, E.; Bronte, G.; Frezza, A. M.; De Lisi, D.; Ceruso, M. S.; Santini, D.; Badalamenti, G.; Pantaleo, M. A.; Russo, A.; Dei Tos, A. P.; Casali, P.; Tonini, G

GoLoco motif proteins binding to Gαi1: insights from molecular simulations

Molecular dynamics simulations, computational alanine scanning and sequence analysis were used to investigate the structural properties of the Gαi1/GoLoco peptide complex. Using these methodologies, binding of the GoLoco motif peptide to the Gαi1 subunit was found to restrict the relative movement of the helical and catalytic domains in the Gαi1 subunit, which is in agreement with a proposed mechanism of GDP dissociation inhibition by GoLoco motif proteins. In addition, the results provide further insights into the role of the “Switch IV” region located within the helical domain of Gα, the conformation of which might be important for interactions with various Gα partners

A kinetic model for the internal motions of proteins: Diffusion between multiple harmonic wells

The dynamics of collective protein motions derived from Molecular Dynamics simulations have been studied for two small model proteins: initiation factor I and the B1 domain of Protein G. First, we compared the structural fluctuations, obtained by local harmonic approximations in different energy minima, with the ones revealed by large scale molecular dynamics (MD) simulations. It was found that a limited set of harmonic wells can be used to approximate the configurational fluctuations of these proteins, although any single harmonic approximation cannot properly describe their dynamics. Subsequently, the kinetics of the main (essential) collective protein motions were characterized. A dual-diffusion behavior was observed in which a fast type of diffusion switches to a much slower type in a typical time of about 1-3 ps, From these results, the large backbone conformational fluctuations of a protein may be considered as "hopping" between multiple harmonic wells on a basically flat free energy surface. (C) 1999 Wiley-Liss, Inc

Imatinib dose escalation versus sunitinib as a second line treatment in KIT exon 11 mutated GIST: a retrospective analysis

We retrospectively reviewed data from 123 patients (KIT exon 11 mutated) who received sunitinib or dose-escalated imatinib as second line.All patients progressed on imatinib (400 mg/die) and received a second line treatment with imatinib (800 mg/die) or sunitinib (50 mg/die 4 weeks on/2 off or 37.5 mg/day). Deletion versus other KIT 11 mutation was recorded, correlated with clinical benefits.64% received imatinib, 36% sunitinib. KIT exon 11 mutation was available in 94 patients. With a median follow-up of 61 months, median time to progression (TTP) in patients receiving sunitinib and imatinib was 10 (95% CI 9.7-10.9) and 5 months (95% CI 3.6-6.7) respectively (P = 0.012). No difference was found in overall survival (OS) (P = 0.883). In imatinib arm, KIT exon 11 deletions was associated with a shorter TTP (7 vs 17 months; P = 0.02), with a trend in OS (54 vs 71 months P = 0.063). No difference was found in patients treated with sunitinib (P = 0.370).A second line with sunitinib was associated with an improved TTP in KIT exon 11 mutated patients progressing on imatinib 400 mg/die. Deletions in exon 11 seemed to be correlated with worse outcome in patients receiving imatinib-based second line