sábado, 27 de janeiro de 2007

Tratamento da degeneração macular: marcha a ré importante.

Esse blog é sempre crítico quanto às novidades. No entanto, em 8/10/07 destacou a importância dos resultados do novo tratamento para da degeneração macular, uma causa cada vez mais importante de cegueira por que associada à idade. No entanto, salvei-me pelo parágrafo onde afirmei que:
Os primeiros ensaios clínicos foram “excitantes”. Vamos aguardar o que virá, porque se confirmar esses resultados a longo prazo com pouco risco haverá um tratamento efetivo para a doença.
Ontem, a Genentech informou que o medicamento em questão aumentou a incidência de acidente vascular cerebral. Em outras palavras, para cada 110 tratamentos, um poderá provocar um caso de doença cerebrovascular. Várias revistas americanas e, uma cópia brasileira, afirmaram que esse foi o maior avanço da medicina em 2006. Infelizmente, não foi o caso. Abaixo a reportagem do The New York Times.
Eye Drug Might Raise Risk of Stroke, Genentech Says By ANDREW POLLACK Published: January 27, 2007 LOS ANGELES, Jan. 26 — Use of Genentech’s new eye drug, Lucentis, might raise the risk of stroke, the company said Friday. The company posted on its Web site a letter it sent to retina specialists this week. According to the letter, 1.2 percent of patients treated with a high dose of Lucentis in a clinical trial suffered a stroke, compared with only 0.3 percent of those treated with a low dose. The difference was statistically significant. The new findings could conceivably damp some demand for Lucentis, because the high dose, 0.5 milligrams per injection, is the one that is marketed. Shares of Genentech fell 89 cents, or 1 percent, to $86.57. Dawn Kalmar, a spokeswoman for Genentech, said Friday that the company wanted to move quickly to communicate the information. But she said the company did not expect the new data to prompt a change in the drug’s label, which already contains a warning about risks of blood-clotting events like strokes. Lucentis, also called ranibizumab, is approved to treat age-related macular degeneration, the leading cause of blindness in the elderly. It is the first drug shown in clinical trials to improve eyesight for a significant number of patients, as opposed to merely slowing the rate of vision loss. Approved in June, the drug had sales of $380 million for the rest of 2006, an amount that greatly exceeded some analysts’ expectations. Genentech executives have cautioned, though, that sales growth may moderate as patients on the drug are treated less frequently. The new data was preliminary, from 2,400 patients who had been followed for an average of 230 days since beginning treatment. The full study will continue and will follow them for a year. Dr. Philip J. Rosenfeld, a retina specialist, said the preliminary data would not influence him because it could later change. “Right now, it will have no impact on my use of Lucentis,” Dr. Rosenfeld, who is at the Bascom Palmer Eye Institute of the University of Miami, said in an e-mail message. “When given a choice between a high likelihood of blindness or a 1 percent risk of stroke, I think most patients will choose their vision.” The label for Lucentis notes a theoretical risk of blood-clotting events like strokes and heart attacks, though it says the rate seen in studies was “low,” at less than 4 percent. In the new study, the rate of heart attacks and deaths from cardiovascular incidents did not differ significantly between the dosages, the company said. The new findings could also raise questions about the risks of Avastin, a cancer drug sold by Genentech. It is being used off-label to treat macular degeneration because it is far cheaper than Lucentis, which costs about $2,000 per monthly injection. Both drugs work by a similar mechanism, although Lucentis was specifically designed to be injected into the eye. Doctors who use Avastin say they have experienced few if any safety problems. But Avastin has not been tested in extensive controlled clinical trials as Lucentis has.

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