Functional Characteristics of C-Terminal Lysine to Cysteine Mutant Form of CTLA-4Ig.

Functional Characteristics of C-terminal Lysine to Cysteine Mutant Form of CTLA-4Ig.

Immune Netw. 2013 Feb; 13(1): 16-24
Kim B, Shin JS, Park CG

CTLA-4Ig is regarded as an inhibitory agent of the T cell proliferation via blocking the costimulatory signal which is essential for full T cell activation. To improve applicability, we developed the CTLA-4Ig-CTKC in which the c-terminal lysine had been replaced by cysteine through single amino acid change. The single amino acid mutation of c-terminus of CTLA-4Ig was performed by PCR and was checked by in vitro transcription and translation. DNA construct of mutant form was transfected to Chinese hamster ovary (CHO) cells by electroporation. The purified proteins were confirmed by Western blot and B7-1 binding assay for their binding ability. The suppressive capacity of CTLA-4Ig-CTKC was evaluated by the mixed lymphocyte reaction (MLR) and in the allogeneic pancreatic islet transplantation model. CTLA-4Ig-CTKC maintained binding ability to B7-1 molecule and effectively inhibits T cell proliferation in MLR. In the murine allogeneic pancreatic islet transplantation, short-term treatment of CTLA-4Ig-CTKC prolonged the graft survival over 100 days. CTLA-4Ig-CTKC effectively inhibits immune response both in MLR and in allogeneic islet transplantation model, indicating that single amino acid mutation does not affect the inhibitory function of CTLA-4Ig. CTLA-4Ig-CTKC can be used in vehicle-mediated drug delivery system such as liposome conjugation. HubMed – drug

Cost-effectiveness of systemic therapies for metastatic pancreatic cancer.

Curr Oncol. 2013 Apr; 20(2): e90-e106
Tam VC, Ko YJ, Mittmann N, Cheung MC, Kumar K, Hassan S, Chan KK

Gemcitabine and capecitabine (gem-cap), gemcitabine and erlotinib (gem-e), and folfirinox (5-fluorouracil-leucovorin-irinotecan-oxaliplatin) are new treatment options for metastatic pancreatic cancer, but they are also more expensive and potentially more toxic than gemcitabine alone (gem). We conducted a cost-effectiveness analysis of these treatment options compared with gem.A Markov model was constructed to examine costs and outcomes of gem-cap, gem-e, folfirinox, and gem in patients with metastatic pancreatic cancer from the perspective of a government health care plan. Ontario health economic and costing data (2010 Canadian dollars) were used. Efficacy data for the treatments were obtained from the published literature. Resource utilization data were derived from a chart review of consecutive metastatic patients treated for pancreatic cancer at Princess Margaret Hospital, Toronto, Ontario, 2008-2009, and supplemented with data from the literature. Utilities were obtained by surveying medical oncologists across Canada using the EQ-5D. Incremental cost-effectiveness ratios (icers) were calculated.The icers for gem-cap, gem-e, and folfirinox compared with gem were, respectively, CA$ 84,299, CA$ 153,631, and CA$ 133,184 per quality-adjusted life year (qaly). The model was driven mostly by drug acquisition costs. Given a willingness-to-pay (wtp) threshold greater than CA$ 130,000/qaly, folfirinox was most cost-effective treatment. When the wtp threshold was less than CA$ 80,000/qaly, gem alone was most cost-effective. The gem-e option was dominated by the other treatments.The most cost-effective treatment for metastatic pancreatic cancer depends on the societal wtp threshold. If the societal wtp threshold were to be relatively high or if drug costs were to be substantially reduced, folfirinox might be cost-effective. HubMed – drug

Immune toxicities and long remission duration after ipilimumab therapy for metastatic melanoma: two illustrative cases.

Curr Oncol. 2013 Apr; 20(2): e165-9
Assi H, Wilson KS

New antitumour immunotherapy strategies for stage iv metastatic melanoma include ipilimumab, a monoclonal antibody against ctla-4. Patterns of response with cancer immunotherapy differ from those with cytotoxic chemotherapy. We present two cases of long-duration immune-related responses with ipilimumab in a phase ii trial. A 66-year-old woman with multiple lung metastases from a scalp primary melanoma received 4 doses of ipilimumab with mixed clinical response. However, after the first maintenance dose, she developed severe ileitis and colitis that responded to steroid therapy. Four months later, she had surgery and radiotherapy for a single brain metastasis. Radiologically, stable disease continued for 36 months after the last ipilimumab dose, and partial response for 5 years after ipilimumab start. A 54-year-old man with cervical lymph node and pulmonary metastases from a scalp primary melanoma received three induction doses of ipilimumab. He developed alopecia universalis and widespread vitiligo, and he discontinued treatment because of hypophysitis. Maintenance ipilimumab was started after a 6-month drug-free interval, with no further adverse events over 15 cycles. At week 12, computed tomography imaging showed no lung metastases and partial response in a supraclavicular lymph node, which was positive on positron-emission tomography. Five years after starting ipilimumab, the supraclavicular lymph node was calcified, and the patient was off steroid therapy and asymptomatic. The foregoing patients demonstrate long responses with ipilimumab (in association with delayed severe colitis in one case, and a constellation of immune events, including alopecia universalis in another). Re-treatment with ipilimumab may be possible even after significant immune adverse events. HubMed – drug