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Uno studio interessante a proposito della equivalenza terapeutica tra farmaci generici e farmaci di marca; gli Autori che dichiarano la loro assenza di conflitti di interesse, (Dr. Kaplan and Dr. McVary have disclosed no relevant financial relationships) fanno notare come in questo studio l'utilizzo dei generici rispetto ai farmaci di marca abbia portato ad un incremento dei valori di PSA, che a loro volta hanno causato numerose biopsie inutili.e se questo avviene in ambito urologico (sottolineano gli autori) figuriamoci se dovesse accadere nei farmaci cardiovascolari, dove le conseguenze negative potrebbero essere enormi (.and urology is just a small piece of the healthcare world. If this is true with cardiovascular drugs, for example, the implications are huge," Dr. McVary said.). I generici, concludono gli autori, rappresentano una fascia importante nel mercato
dei farmaci ma senza dubbio la loro qualità deve essere verificata sin dall’inizio del
processo di registrazione e quindi sorvegliata (."Generics are an important part of
our healthcare system, but the generic houses are under scrutiny," Dr. McVary
pointed out.) .
Di seguito tutto l’articolo in originale Medscape Conference Coverage, based on selected sessions at the: American Urological Association (AUA) 104th Annual Scientific Meeting
• AUA 2009: Generics Not Equal to Brand-Name Drugs for Overactive Bladder May 3, 2009 (Chicago, Illinois) — A comparison of brand-name oxybutynin with generic substitutes for overactive bladder shows that the bioequivalence in generic formulations can vary from 80% to 125% of the branded drug, investigators announced here at the 2009 annual meeting of the American Urological Association. Steven A. Kaplan, MD, from the Department of Urology at Weill Cornell Medical
Center in New York, and colleagues evaluated 156 consecutive patients with
overactive bladder, 87 women and 69 men. Subjects were switched from brand-
name Detrol LA, Vesicare, Enablex, or Sanctura XR to generic oxybutynin, either by
their primary care physician or because of insurance reasons.
Patients completed 3-day diaries prior to the switch and after 8 weeks of treatment
with the generic drug. Treatment-related changes were assessed by 24-hour
daytime and nocturnal micturitions, development of urge and urge incontinence and
International Prostate Symptom Score (IPSS) in men. Safety was assessed by
changes in postvoid residual urine and adverse events.
In women, there was a doubling of daytime frequency of urination, a slight 20%
increase in nocturia, and a 46.3% increase in urge incontinence.
In men, there was a 2.4-fold increase in daytime frequency, a 40% increase in
nocturia, and a 40.6% increase in urge incontinence. In addition, there was a 3.7-
point increase in IPSS.
Postvoid residual volume increased 14.7 mL in women and 19.7 mL in men. In
addition, there were increased adverse effects in both sexes. Incidence of dry
mouth increased 23.1% in women and 14.3% increase in men, and incidence of
constipation increased 32.1% in women and 34.6% in men.
"Switching from Detrol LA and Vesicare to generic oxybutinin resulted in the
greatest changes in safety and efficacy" (P < .01), Dr. Kaplan told Medscape Urology
after his presentation.
"In 1984, 12% of prescriptions were generic. In 2007, 65% were generic, and it's
been growing about 12% per year compared with branded prescriptions," he
commented.
"Bioequivalence can vary from 80% to 125% of the brand-name drug.
Bioequivalence does not equal therapeutic equivalence," he warned. "The approval
process is much different for generic drugs.
"When we looked at changes in [prostate specific antigen] (PSA) levels among men
on Avodart switched to the generic formulation, we saw a greater than 0.75 ng/mL
increase at 3 months in 34% of men. That is an increase that would ordinarily trigger
a biopsy, but I put them back on the brand-name drug. The PSA came down in all
cases, and none of them needed a biopsy."
"This is a much more serious problem than I was aware of," AUA spokesman Kevin
T. McVary, MD, professor of urology at Northwestern University Feinberg School of
Medicine in Chicago, Illinois, commented in an interview with Medscape after
listening to Dr. Kaplan's findings. "Cost drives the process of generic prescriptions
over brand-name dispensation, so I don't see the situation changing unless the
word gets out.
"Generics are an important part of our healthcare system, but the generic houses
are under scrutiny," Dr. McVary pointed out.
"The findings on increasing PSA level, especially as a trigger for unnecessary
biopsy, is particularly compelling. I am going to have to review my prescribing
habits. And urology is just a small piece of the healthcare world. If this is true with
cardiovascular drugs, for example, the implications are huge," Dr. McVary said.
"I always sign my prescriptions 'dispense as written,' which we can opt to do in New
York," Dr. Kaplan said. "When the insurance companies call me on it, I just tell them
that the science supports it."
In the meantime, "looking at how generic drugs are approved is a start," Dr. Kaplan
said.
Dr. Kaplan and Dr. McVary have disclosed no relevant financial relationships.
American Urological Association (AUA) 104th Annual Scientific Meeting: Abstract
1870. Presented April 28, 2009

Source: http://www.snamipa.it/Farmaci%20Generici%20in%20urologia.pdf