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>Roche and Novartis compete in Parkinson's
>
>Roche has fired the opening shots in what looks likely to be a direct
>battle between two new Parkinson's
>disease therapies from Roche and Orion/Novartis.
>
>At a Roche symposium during the 7th International Symposium on Parkinson's
>Disease, in London on March
>23rd-26th, the company claimed superiority of tolcapone over Orion's
>entacapone (to be co- marketed with
>Novartis).
>
>Tolcapone and entacapone are the first of a new class of drugs for
>Parkinson's, which inhibit the enzyme,
>catechol-O-methyltransferase (COMT), found in serum and the brain. COMT
>degrades both dopamine and its
>precursor, levodopa, which is the current mainstay of treatment for
>Parkinson's. COMT inhibitors increase brain
>dopamine levels, making them potential adjunct therapies to levodopa.
>Patients who have been taking levodopa
>for several years generally start to experience sharp fluctuations in motor
>ability. COMT inhibitors improve
>symptom control in such patients, and allow the levodopa dose to be reduced.
>
>Tolcapone seems likely to be the first to market, as it was approved in
>Switzerland (as Tasmar) in February for
>fluctuating and non- fluctuating Parkinson's. Roche told Scrip the CPMP had
>given it a positive opinion
>(presumably at its March meeting - Ed; Scrip No 2219 /20, p 4) and is
>aiming for a European launch sometime
>this year. In the US, the company says it is "in the process of filing".
>
>Orion has completed Phase III trials with entacapone, but would not comment
>on when it expects to file for
>approval. Novartis has joint marketing rights in most European countries
>(except for Scandinavia and the Baltic
>Republics) and sole marketing rights in the US (Scrip No 2108, p 7).
>
>Clinical data
>Placebo-controlled studies have shown similar clinical efficacy for
>tolcapone 100mg or 200mg three times daily,
>and entacapone 200mg four to ten times daily (with each levodopa dose), but
>the two drugs have not been
>directly compared. Tolcapone has the advantage of a less frequent dosing
>schedule, although it was noted that the
>higher entacapone dose frequency would presumably not greatly inconvenience
>patients as it is merely added to
>each levodopa dose, and levodopa itself is often taken several times a day.
>
>The companies presented clinical data at the recent Parkinson's meeting.
>Both drugs allowed reductions in
>levodopa dosage, and caused improvements in on/off time ("on time" is when
>symptoms are under control; "off
>time" results in dyskinesias and immobility) and in the United Parkinson's
>Disease Rating Scale. One of Roche's
>trials showed an increase in "on time" of about 25% with tolcapone 200mg
>tid; studies also suggest an
>improvement in quality of life for non- fluctuating patients. In one of
>Orion's studies, patients on entacapone
>200mg four to ten times daily experienced a mean increase in daily "on
>time" from 9.3 hours to 10.7 hours
>(+15%). (Other results with entacapone were reported in Scrip No 2140, p 23.).
>
>At the symposium, Roche devoted a session to comparing pharmacokinetic and
>pharmacodynamic data for both
>drugs, highlighting tolcapone's higher efficacy per unit dose and longer
>half-life. The company claimed that,
>"based on the available data, tolcapone appears to be a more potent COMT
>inhibitor than entacapone at equal
>doses". It also noted that while both drugs inhibit peripheral COMT, only
>tolcapone seems to affect central
>COMT.
>
>Orion rejected these claims, saying that pharmacokinetic data were less
>relevant than clinical trials showing
>similar efficacy for both drugs. The company also suggested to Scrip that
>tolcapone's central effects may have
>"safety implications".
>
>Some delegates thought it erroneous to draw conclusions about the relative
>efficacies before direct comparative
>studies have been performed. "Head-to-head trials are needed before any
>claims can be made, " said Dr Mark
>Guttmann of the University of Toronto, who has had experience with both
>drugs. He thinks that ultimately the
>market leader may be determined by issues such as cost and availability.
>
>Source: Scrip. 9th April 1997.
>
>Tolcapone is licensed in Switzerland.
>
>
>