set analysis showed that tumor EGFR e x pres sion doesn't predic t benef it towards the cetuximab containing regimen. A phase II trial with cetuximab +/ gemcitabine and cisplatin showed similar AG-1478 negative results . The objective response rate was 17. 5% for the combination arm versus 12. 2% in control, and median progression absolutely free and overall survivals had been 4. 2 months vs 3. 4 months, and 7. 8 months vs 7. 5 months respectively. Anti angiogenesis Pancreas cancer was thought to thrive on neovascularization and dependent on a rich blood supply as the tumors grow . The significance of vascular endothelial growth factor pathway was shown in preclinical pancreas cancer studies .
Although the exact mechanism in patients is unclear, anti angiogenic therapies are thought to interrupt tumor neovascularization and normalize existing inefficient tumor vasculature, thereby enhancing drug AG-1478 delivery and synergize the effects of cytotoxic agents. Bevacizumab, a MoAb to VEGF ligand was studied in multiple trials. Recently published CALGB 80303 treated 535 patients and overall response rates, median OS and PFS had been 13%, 5. 8 months, and 3. 8 months for the gemcitabine/ bevacizumab arm and 10%, 5. 9 months, and 2. 9 months for the gemcitabine/placebo arm, respectively . When bevacizumab was eva luated in combinat ion with gemcitabine and erlotinib, the phase I I I tr ia l failed to demonstrate significant improvement by the bevacizumab conta ining arm compared to control . Bevacizumab failed to improve survival when evaluated in combination with gemcitabine and capecitabine in a phase II trial .
Despite the intial excitement, bevacizumab Lapatinib failed to improve survival in advanced pancreas cancer patients when evaluated in combination with normal of care. Quite a few smaller molecular tyrosine kinase inhibitors against VEGFR2, which includes sorafenib, sunitinib and vatalatinib, have being evaluated within the disease but none showed optimistic efficacy signal so far . Combination therapies targeting VEGFRs along with other signaling pathways are under investigation. Insulin like growth factor pathway The IGF axis comprises multiple circulating ligands, for example IGF 1, IGF II and insulin, interacting with membrane bound receptors, for example type I IGF receptor . The PI3k Akt pathway is a single key downstream mediator of IGF 1R signaling and plays a potentially important role in anticancer drug resistance .
IGF 1R has been shown in preclinical studies to mediate resistance to EGFR inhibition, and co targeting of both receptors enhances the abrogation of PI3k Akt activity and reduces survivin expression . Transgeneic mouse models of pancreas cancer expressing high levels of IGF 1R showed increased invasive carcinomas and lymph node metastases . Targeting of IGF 1R expression by siRNAs achieved growth inhibition in several gastrointestinal malignancies, suggesting potential significance of the pathway in pancreas cancer . In concert, changing IGF 1R copy number by cDNA plasmid augmented mitogenic response in mouse embryo. Remedies with MoAb seemed to bring about IGF 1R internalization and degradation, and enhanced cytotoxic chemotherapy effects .
DNA repair pathways are other downstream effectors of IGF 1R axis and supply the rationale for combining IGF 1R inhibitors with cytotoxics . Quite a few agents targeting IGF 1R, both MoAbs and TKIs, are been evaluated clinically and we are just starting to realize their clinical role and potential mechanisms of resistance to this class of drugs . Anti IGF 1R monoclonal antibodies AMG 479 is really a totally humanized MoAb that blocks the binding of IGF I and IGF II to IGF 1R , and doesn't cross react with all the insulin receptor . AMG 479 totally inhibited l igandinduced dimerization and activation of IGF 1R/IGF 1R and IGF 1R/IR in two pancreas cancer cell lines. The antibody decreased IGF 1R mediated downstream Akt phosphorylation with pro apoptotic and anti proliferative effects within the cancer cell lines.
The agent demonstrated additive effects with gemcitabine in preclinical studies . In a randomized phase II trial, AMG 479 in combination with gemcitabine demonstrated a trend to improvement in median survival when compared to the placebo/gemcitabine control arm in previously untreated metastatic pancreas cancer patients. The median PFS was 5. 1 months and 2. 1 months respectively . The investigators conclude that there was adequate efficacy signal to warrant further evaluation in a phase III trial. IMC A12 a nd MK 0 6 4 6 are other anti IGF 1R MoAb which are being evaluated in untreated metastatic pancreas cancer patients. MK 0646 enhanced gemcitabine induced apoptosis in preclinical studies and is being evaluated clinically. This phase I/II trial is enrolling patients to 3 therapy arms; A: gemcitabine 1000mg/m2 weekly × 3 with MK 0646 weekly × 4, Arm B: gemcitabine MK 0646 erlotinib 100mg daily, Arm C: gemcitabine 10 0 0mg /m2 week ly × 3 erlot inib 10 0mg da i ly. MK 0646 achieved 6 partial responses , 1 hepatic total response a
Friday, October 18, 2013
Advanced Bit By Bit Map For AG-1478Lapatinib
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