Paliperidone: Cost Effective (?)

This is a peculiar article: href="http://www.annals-general-psychiatry.com/content/7/1/16/abstract">Costs
and effects of paliperidone extended release compared with alternative
oral antipsychotic agents in patients with schizophrenia in Greece: A
cost effectiveness study.  It's a
open-access article in the Annals of General Psychiatry, dated 28
August, 2008. (Annals of General Psychiatry 2008, 7:16
doi:10.1186/1744-859X-7-16)

Background To compare the costs
and effects of paliperidone extended release (ER), a new pharmaceutical
treatment for the management of schizophrenia, with the most frequently
prescribed oral treatments in Greece (namely risperidone, olanzapine,
quetiapine, aripiprazole and ziprasidone) over a 1-year time period.



Methods A decision tree was developed and tailored
to the specific circumstances of the Greek healthcare system.
Therapeutic effectiveness was defined as the annual number of stable
days and the clinical data was collected from international clinical
trials and published sources. The study population was patients who
suffer from schizophrenia with acute exacerbation. During a consensus
panel of 10 psychiatrists and 6 health economists, data were collected
on the clinical practice and medical resource utilisation. Unit costs
were derived from public sources and official reimbursement tariffs.
For the comparators official retail prices were used. Since a price had
not yet been granted for paliperidone ER at the time of the study, the
conservative assumption of including the average of the highest
targeted European prices was used, overestimating the price of
paliperidone ER in Greece. The study was conducted from the perspective
of the National Healthcare System.



Results The data indicate that paliperidone ER
might offer an increased number of stable days (272.5 compared to 272.2
for olanzapine, 265.5 for risperidone, 260.7 for quetiapine, 260.5 for
ziprasidone and 258.6 for aripiprazole) with a lower cost compared to
the other therapies examined (€7,030 compared to
€7,034 for olanzapine, €7,082 for risperidone,
€8,321 for quetiapine, €7,713 for ziprasidone and
€7,807 for aripiprazole). During the sensitivity analysis, a
± 10% change in the duration and frequency of relapses and
the economic parameters did not lead to significant changes in the
results.



Conclusion Treatment with paliperidone ER can lead
to lower total cost and higher number of stable days in most of the
cases examined.

At first glance, it seems fairly straightforward.
 Second-generation antipsychotics are expensive.
 There have been many studies on the cost-effectiveness.
 This one is fairly typical.  Except for the timing.

You see, generic risperidone has just recently
become available, at least in the USA.  Paliperidone is the
active metabolite of risperidone.  Paliperidone does have some
advantages, but in general it is fairly comparable to risperidone.
 



The study shows that paliperidone may have a slight advantage in
efficacy.  Given that the cost cited for paliperidone is
slightly lower than the cost cited for risperidone, it would follow
paliperidone would be more cost-effective.



But what if they used today's costs?



At this moment, Drugstore.com lists Invega 9mg capsules, #100 for
$1,638.95.  (Invega in the brand name for paliperidone ER.)
They list generic risperidone, #180, for $869.98.  Typically a
person would take one Invega 9mg capsule per day, or two 3mg
risperidone per day.  Using those figures, the treatment with
Invega would cost $16.39 per day.  Generic risperidone would
cost $9.67 per day.



Usually, when a generic drug is first marketed, it comes out at a
relatively small discount compared to the branded product.
 After about six months, the price tends to decline even more.
 So the price differential is going to increase pretty soon.



I suspect that the authors would arrive at a very different conclusion
about the cost-effectiveness, if they were to run their models using
updated cost figures.



Oh, and one of the authors of the paper works for Janssen, the maker of
Invega.  They also make Risperdal (the branded version of
risperidone.)  Janssen stands to lose market share, as
Risperdal was one of the flagship products, and there is now a generic
version.  The generic risperidone will compete with their new
product, Invega.  It sure would be nice, for them, if they
could show a convincing reason to prescribe the new product.
 Unfortunately, the study that showed an economic advantage
was out of date almost as soon as it was published.