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Blinatumomab
Blinatumomab, sold under the brand name Blincyto, and known informally as blina,[5] is a biopharmaceutical medication used as a second-line treatment for Philadelphia chromosome-negative relapsed or refractory acute lymphoblastic leukemia. It belongs to a class of constructed monoclonal antibodies, bi-specific T-cell engagers (BiTEs), that exert action selectively and direct the human immune system to act against tumor cells. Blinatumomab specifically targets the CD19 antigen present on B cells.[6] In December 2014, it was approved by the US Food and Drug Administration under the accelerated approval program; marketing authorization depended on the outcome of clinical trials that were ongoing at the time of approval.[7][8] Blinatumomab is given via intravenous infusion.[7] Medical useBlinatumomab was originally approved to treat Philadelphia chromosome-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia in adults and children.[9] It is approved by the US Food and Drug Administration (FDA) for B-cell precursor acute lymphoblastic leukemia (ALL) in first or second complete remission with minimal residual disease greater than or equal to 0.1% as well as relapsed or refractory B-cell precursor ALL.[7] Mechanism of action Blinatumomab is a bispecific T-cell engager (BiTE).[7] It enables a patient's T cells to recognize malignant B cells. A molecule of blinatumomab combines two binding sites: a CD3 site for T cells and a CD19 site for the target B cells. CD3 is part of the T cell receptor. The drug works by linking these two cell types and activating the T cell to exert cytotoxic activity on the target cell.[10] CD3 and CD19 are expressed in both pediatric and adult patients, making blinatumomab a potential therapeutic option for both pediatric and adult populations.[11] HistoryThe drug (originally known as MT103) was developed by a German-American company Micromet, Inc. in cooperation with Lonza; In 2012, Micromet was purchased by Amgen, which furthered the drug's clinical trials. In July 2014, the FDA granted breakthrough therapy status to blinatumomab for the treatment of acute lymphoblastic leukemia (ALL).[12] In October 2014, Amgen's Biologics License Application for blinatumomab was granted priority review designation by the FDA, thus establishing a deadline of 19 May 2015, for completion of the FDA review process.[13] On 3 December 2014, the drug was approved for use in the United States to treat Philadelphia chromosome-negative relapsed or refractory acute lymphoblastic leukemia under the FDA's accelerated approval program; marketing authorization depended on the outcome of clinical trials that were ongoing at the time of approval.[7][14] CostWhen blinatumomab was approved, Amgen announced that the price for the drug would be US$178,000 per year, which made it the most expensive cancer drug on the market. Merck's pembrolizumab was priced at US$150,000 per year when it launched (in September 2014).[15] At the time of initial approval, only about 1,000 patients in the US had an indication for blinatumomab.[15] Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan-Kettering Cancer Center, calculated that according to "value-based pricing," assuming that the value of a year of life is US$121,000 with a 15% "toxicity discount," the market price of blinatumomab should be US$12,612 a month, compared to the market price of US$64,260 a month. A representative of Amgen said, "The price of Blincyto reflects the significant clinical, economic and humanistic value of the product to patients and the health-care system. The price also reflects the complexity of developing, manufacturing and reliably supplying innovative biologic medicines."[16] References
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