A goal of personalized medicine as applied to oncology is to identify compounds that exploit a defined molecular defect in a cancerous cell. A compound called procaspase-activating compound 1 (PAC-1) was reported that enhances the activity of procaspase-3 in vitro and induces apoptotic death in cancer cells in culture and in mouse xenograft models. Experimental evidence indicates that PAC-1 activates procaspase-3 in vitro through chelation of inhibitory zinc ions. Described herein is the synthesis and biological activity of a family of PAC-1 derivatives where key functional groups have been systematically altered. Analysis of these compounds reveals a strong correlation between the in vitro procaspase-3 activating effect and their ability to induce death in cancer cells in culture. Importantly, we also show that a fluorescently-labeled version of PAC-1 co-localizes with sites of caspase-3 activity in cancer cells. The data presented herein further bolster the hypothesis that PAC-1 induces apoptosis in cancer cells through the direct activation of procaspase-3, has implications for the design and discovery of next-generation procaspase-3 activating compounds, and sheds light on the anti-apoptotic role of cellular zinc.
A critical event in the apoptotic cascade is the proteolytic activation of procaspases to active caspases. The caspase autoactivating compound PAC-1 induces cancer cell apoptosis and exhibits antitumor activity in murine xenograft models when administered orally as a lipid-based formulation or implanted s.c. as a cholesterol pellet. However, high doses of PAC-1 were found to induce neurotoxicity, prompting us to design and assess a novel PAC-1 derivative called S-PAC-1. Similar to PAC-1, S-PAC-1 activated procaspase-3 and induced cancer cell apoptosis. However, S-PAC-1 did not induce neurotoxicity in mice or dogs. Continuous i.v. infusion of S-PAC-1 in dogs led to a steady-state plasma concentration of ∼10 μmol/L for 24 to 72 hours. In a small efficacy trial of S-PAC-1, evaluation of six pet dogs with lymphoma revealed that S-PAC-1 was well tolerated and that the treatments induced partial tumor regression or stable disease in four of six subjects. Our results support this canine setting for further evaluation of small-molecule procaspase-3 activators, including S-PAC-1, a compound that is an excellent candidate for further clinical evaluation as a novel cancer chemotherapeutic. Cancer Res; 70(18); 7232-41. ©2010 AACR.
For Abstract see ChemInform Abstract in Full Text.
Background Pembrolizumab, a monoclonal antibody against programmed death ligand 1 (PD-L1), is approved by several regulatory agencies for first-line treatment of metastatic non-small-cell lung cancer (NSCLC) with a PD-L1 tumor proportion score (TPS) ≥ 50% and no epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase genomic tumor aberrations. This study was conducted from the perspective of the Hospital Authority in Hong Kong and aimed to evaluate the cost effectiveness of a biomarker (PD-L1) test-and-treat strategy (BTS), in which patients with a TPS ≥ 50% received pembrolizumab and other patients received platinum doublet chemotherapy versus all patients receiving platinum doublet chemotherapy. Methods The model used a partitioned survival approach to estimate the incremental cost-effectiveness ratio (ICER) expressed as the cost per quality-adjusted life-year (QALY) gained. The clinical efficacy, utility and safety data were derived from the KN024 trial. Costs and health outcomes were projected over a 10-year time horizon and discounted at 3% per year. Costs for drug acquisition, PD-L1 testing, drug administration and disease management were used. Sensitivity analyses were conducted to evaluate the robustness of results. Results The BTS approach led to an increase of 0.29 QALYs at an additional cost of Hong Kong dollars (HK$) 249,077 (US$31,933) compared with platinum doublet chemotherapy, resulting in an ICER of HK$865,189 (US$110,922) per QALY gained. This is lower than the World Health Organization cost-effectiveness threshold of three times the 2016 gross domestic product (GDP) per capita for Hong Kong of HK$1017,819 (US$130,490). Probabilistic sensitivity analyses showed a 59.4% chance that the ICER would be below this threshold. Conclusion First-line treatment with pembrolizumab in a BTS to identify patients with NSCLC with PD-L1 TPS ≥ 50% can be considered cost effective in Hong Kong compared with platinum doublet chemotherapy based on a three-times GDP per capita threshold. However, local data on clinical efficacy and safety were not available to estimate overall survival (OS) and progression-free survival (PFS) specific to patients with NSCLC in Hong Kong. Further, uncertainty is inherent in the survival projections/extrapolation of PFS and OS beyond the trial period, and future research may help to further inform these parameters.A programmed death ligand 1 (PD-L1) test-and-treat strategy for the use of pembrolizumab in patients undergoing first-line treatment for non-small-cell lung cancer (NSCLC) with PD-L1 expression ≥ 50% is associated with a gain of 0.29 quality-adjusted life-years (QALYs), at an additional total cost of Hong Kong dollars (HK$) 249,077 per patient compared with platinum doublet chemotherapy (incremental cost-effectiveness ratio [ICER] of HK$865,189 per QALY gained) (year 2016 values).Key cost-effectiveness drivers were the drug acquisition costs and projections of improved survival.The ICER was below the threshold of three times gross domestic product per capita fo...
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