Note:
(a) summary underneath the title in print: Some Hong Kong pharmacies sell under-the-counter cancer drugs
(b) "Hong Kong’s Nathan Road is a favorite destination for tourists from the mainland. Li, a visitor from Hebei province who declined to give her first name, came in search of another foreign brand: Herceptin, a breast cancer drug from Roche Holding. Li found a pharmacy in the area that would sell her some without a prescription [which is illegal in HK: ‘The maximum penalty for illegal possession and sale of prescription medicines is a fine of HK$100,000 and two years in prison’], for a cousin back home who’s been diagnosed with the disease. The price she paid—HK$20,000 ($2,580) for a 440-milligram vial—was about 30 percent lower than in some parts of China."
(i) Nathan Road 彌敦道
https://en.wikipedia.org/wiki/Nathan_Road
(the main thoroughfare in Kowloon, Hong Kong that goes in a south-north direction; was the very first road built [in 1861] in Kowloon, after the land was ceded by the Qing Dynasty government to the United Kingdom in 1860 [Hong Kong Island ceded in 1842]; name changed to current name, after Matthew Nathan, HK governor 1904 - 1907)
(ii) For the drug, a trade name is Herceptin, and United States Adopted Name (USAN) is trastuzumab (where mab indicates it is a Monoclonal AntiBody).
(A) A growth factor is produced and exerts its influence locally, whereas a hormone circulates in blood and affect distant targets.
(B) The epidermal growth factor (EGF) binds to its own receptor called EGFR (R for receptor). (In fact, in any species there are a family of EGF and a family of receptors, with members in a family closely related to one another.) HER2 (Human Epidermal growth factor Receptor 2) is one of the EGFR in humans.
(C) Breast cancer cells in some humans overexpress HER2 on their surface (and thus have its growth accelerated by EGF). (Breast cancer of this type has a worse prognosis -- earlier relapse and death -- than breast cancer without HER2.) When Herceptin binds specifically HER2, the cancer cells are marked for destruction, in a phenomenon called antibody dependent cellular cytotoxicity (ADCC).
Proposed Mechanism of Action. Herceptin.com, undated (video).
www.herceptin.com/hcp/treatment/moa
(D) Herceptin received initial US approval (from FDA) in 1998. Administered through intravenous infusion (oral route will result in digestion of the protein: antibody is basically a protein).
(E) Based in South San Francisco, california, Genentech developed Herceptin. Roche acquired Genentech in 2009.
(F) Highlights of Prescribing Information. Genentech, 2015.
www.gene.com/download/pdf/herceptin_prescribing.pdf
Quote:
"A vial contains 440mg herceptin as a lyophilized, sterile powder." page 1
a typical dosage: "Initial dose of 4 mg/kg over 90 minute IV infusion, then 2 mg/kg over 30 minute IV infusion weekly for 52 weeks" page 1
"Reconstitute each 440 mg vial of Herceptin with 20 mL of Bacteriostatic Water for Injection (BWFI), USP, containing 1.1% benzyl alcohol as a preservative to yield a multi-dose solution containing 21 mg/mL trastuzumab. * * * Store reconstituted Herceptin at 2−8○C; discard unused Herceptin after 28 days. If Herceptin is reconstituted with SWFI without preservative, use immediately and discard any unused portion." page 4
(G) "Initial dose of 4 mg/kg over 90 minute IV infusion, then 2 mg/kg over 30 minute IV infusion weekly for 52 weeks."
Namely, a loading dose of 4 mg/kg of body weight. "Patients should be observed for fever and chills or other infusion-associated symptoms." Subsequently weekly maintenance dose of Herceptin is 2 mg/kg body weight.
(H) Hence a vial of 440mg can not last a month.
|
发表于 11-10-2015 19:28:41
收藏
分享
支持
反对
楼主