Archives du mot-clé Avastin

« Anti-VEGF et DMLA » au DU « Angiographie et Pathologie Rétinienne 2008 »

Petite mise à jour des diapositives concernant les anti-VEGF et leur utilisation en traitement de la DMLA exsudative, pour le DU « Angiographie et Pathologie Rétinienne » 2008 (18 juin 2008) :

Ces fichiers sont à votre disposition pour une utilisation personnelle (consultation) :
aucun élément ne peut être diffusé sans mon autorisation.
N’hésitez pas à me contacter pour toutes questions.

NB : Vous trouverez quelques détails sur l’étude VERITAS, dont je n’avais pas connaissance en préparant ce diaporama, dans le billet d’hier…

Disponibilité de l’Avastin : accord entre Genentech et ophtalmologistes américains

En cette période de « trêve des confiseurs« , un accord semble avoir été trouvé entre Genentech (le fabriquant de Lucentis et Avastin) et ophtalmologistes américains, qui permettra donc à ces derniers de continuer à s’approvisionner en Avastin.

Les ophtalmologistes pourront en effet le commander directement auprès de grossistes, qui livreront le médicament, au choix, soit à une pharmacie hospitalière, soit à une « compounding » pharmacie, soit au praticien lui même.

Bien que la mise en place de cette « filière » puisse varier selon les états, cette décision marque donc un signe de bonne volonté du laboratoire pour permettre l’accès à l’Avastin.

Source : OSN, New York Times.

En savoir plus :

Avastin vs. Lucentis : l’étude CATT sur le point de démarrer

Nous avons parlé à plusieurs reprises de la nécessité de comparer les traitements de la DMLA par médicaments anti-VEGF entre eux : l’étude américaine « Avastin vs. Lucentis » semble enfin être sur le point de démarrer, si l’on en croit le billet de Irv Arons sur son blog.

L’étude CATT (pour « Comparison of Age-related macular degeneration Treatments Trials »), multicentrique (40 centres aux USA) randomisée, prévoit d’inclure 1200 patients atteints de DMLA, répartis en 4 groupes thérapeutiques :
(1) Injections mensuelles de Lucentis;
(2) Injections mensuelles d’Avastin;
(3) Trois injections de Lucentis, puis réinjections « à la demande »;
(4) Trois injections d’Avastin, puis réinjections « à la demande ».
Le critère de jugement principal sera l’acuité visuelle, mais seront aussi évalués la taille et l’aspect en OCT des lésions néovasculaires.

Les inclusions devraient débuter d’ici fin 2007, avec un suivi de 2 ans : les premiers résultats (suivi à un an) sont espérés courant 2009.

Il nous faut donc attendre encore 2 ans pour avoir les premiers éléments objectifs de comparaison d’Avastin et Lucentis; outre des conséquences médico-économiques majeures, cette étude pourrait également nous apporter de précieux renseignements sur le rythme d’administration optimal de ces nouveaux traitements…

Lien : http://www.med.upenn.edu/cpob/studies/CATT.shtml

Avastin vs. Lucentis dans Wall Street Journal

Lecture utile en complément de l’article du Figaro du 19 février, ce long article du Wall Street Journal du 22 février expose l’histoire de la « guerre » Lucentis vs. Avastin, repris sur HealthDecisions.org ou sur le blog de I. Arons.
Cet article revient notamment sur :

  • l’impact financier de l’utilisation de l’un ou l’autre des traitements, pour les patients ou la collectivité d’une part, et le laboratoire d’autre part :
  • Over the recommended two-year course of monthly injections into the eye, the bill for Lucentis reaches nearly $50,000. While Medicare covers 80% of the treatment cost for the elderly, some patients must pay the rest themselves.

    Officials at the center, which administers Medicare, project that Lucentis could over time cost taxpayers more than $1 billion a year and possibly as much as $3 billion annually.

    The Lucentis-Avastin showdown has thrown the pharmaceutical world into a tizzy. Genentech, fearful that a potential billion-dollar-a-year product could be headed down the tubes, is urging doctors to stick to Lucentis and its proven efficacy in treating age-related macular degeneration. Doctors are weighing benefit and cost — and often choosing to roll the dice with Avastin, although it is approved only as a cancer treatment, to ensure that less well-off patients get treatment.

    Now the federal government is hoping to settle the dispute by funding a head-to-head comparison of the two biotechnology drugs, the first such trial by the National Institutes of Health. If Avastin works as well as Lucentis, the government’s Medicare program for the elderly could save $1 billion or more a year, officials say.

    For Genentech, the world’s second-largest biotechnology company by revenue after Amgen Inc., the stakes are high. Lucentis was a surprise hit after its June 30 launch, logging $10 million in sales on its first day and $371 million in the second half of 2006. Eric Schmidt, an analyst at Cowen & Co., estimates the figure could reach $900 million this year and rise to $1.3 billion by 2011.

  • le développement du Lucentis, dérivé de l’Avastin :
  • « This isn’t Avastin Jr., » insists Dr. Semba, the Lucentis development leader.

    Genentech, in justifying the cost of Lucentis, says its trials of the drug included more than 6,000 patients who received vision tests, retinal scans and monthly doctor checkups. It was « one of the more expensive clinical trials we’ve run, » says Ronald Park, team leader for pricing. He notes that older drugs for AMD cost nearly $1,000 a dose without improving vision. Lucentis « is a breakthrough drug for a very bad disease, » says Dr. Park.

    Joining Genentech in 1989, Dr. Ferrara and colleagues reported they had isolated the vessel stimulant VEGF, or vascular endothelial growth factor. Later they sequenced the gene for VEGF and worked on protein molecules called monoclonal antibodies that block it. That led to Avastin.

    In addition to the monkey studies that suggested Avastin molecules couldn’t reach the retina, there were other reasons Genentech didn’t push the drug hard as an eye treatment. Avastin was designed for cancer patients who need the drug to stick around in their bodies to do its work. Although that could raise the risk of cardiovascular problems associated with Avastin, it was worth it for cancer patients facing a terminal disease.

    For elderly people with eye disease, Genentech wanted a drug that would home in on the retina, do its work and quickly get eliminated from the body. The drug it found, Lucentis, binds 20 times better to VEGF in retinal cells and is safer, Dr. Ferrara says.

  • l’origine de l’utilisation de l’Avastin « off-label » en ophtalmologie :
  • In July 2005, Genentech reported the results of a big Phase III study of Lucentis before a hushed crowd of 2,000 at a medical meeting in Montreal. The studies showed it halted blindness in 90% of people with AMD and improved vision in 30%.[…] The only problem: Approval would take another year.

    Then came an apparent solution: At the same meeting, Philip Rosenfeld, a professor at the Bascom Palmer Eye Institute of the University of Miami Medical School, presented a case of a patient who had been going blind and was injected with Avastin. The patient’s retinal scans dramatically improved a week after treatment and vision began to regain sharpness over six months. […] Rather than wait until Lucentis was approved by the FDA, many doctors grasped at the next best thing. With the help of compounding pharmacists who siphoned tiny doses of Avastin into small syringes, eye doctors tried it in thousands of patients. In large doses for cancer, Avastin costs $55,000 a year. The dose used in the eye costs just $20 to $100.

  • l’équivalence apparente entre les deux traitements, tant sur le plan de l’efficacité qu’en terme de tolérance :
  • But some specialists say the two drugs, despite their differences, might be equally effective. Dr. Avery, who has a research appointment at the University of California, Santa Barbara, decided in 2005 to do the kind of study Genentech had long ago lost interest in performing. He and Israeli colleague Anat Loewenstein injected Avastin into rabbits’ eyes. The conclusion, says Dr. Avery: « Hey, this does get through the retina. » They published the findings in the journal Retina in February 2006.

    Moreover, in a safety challenge to Genentech, Dr. Fung in San Francisco teamed up with Dr. Rosenfeld in Miami, devising an Internet survey to seek swift reports of serious side effects from Avastin.

    In a snapshot of more than 5,200 eye patients on Avastin, their survey found four strokes including one death in a person with risk factors, an unsurprising rate for older people, the doctors reported in the British Journal of Ophthalmology in November 2006.

    Lucentis itself may raise stroke risk. In late January, Genentech sent out a « Dear Doctor » letter noting that patients taking the recommended dose of Lucentis had a higher rate of strokes (1.2%) than patients taking a smaller dose (0.3%).

  • la nécessité d’une étude comparative… et la difficulté de son financement, auquel on ne peut attendre aucune aide des firmes pharmaceutiques :
  • With billions of dollars at stake and medical questions unanswered, the National Eye Institute plans to start a two-year trial in May or June to compare safety and efficacy of Avastin versus Lucentis. While the NIH has previously run tests comparing newer brand-name drugs against older and cheaper generics, this is the first time it is pitting two brand-name biotech drugs against each other, says Dr. Ferris, the eye institute’s clinical director. He says the government must conduct the study because it needs to ensure that the widespread use of Avastin is safe.

    However, funding for the trial remains uncertain. In part because the government has to purchase all of its Lucentis and Avastin supplies, the eye institute says it can’t afford to fund the trial on its own and is seeking help from Medicare.