This is free market research on the Parkinson's disease treatment industry and can include information on the background, market structure, definitions, competitors, trends and developments of Parkinson's disease treatment and is related to other topics such as drugs and health.

Kyowa Hakko: non-approvable letter for Parkinson's treatment

The FDA has issued a non-approvable letter for Kyowa Hakko's new treatment for Parkinson's disease.

The FDA's non-approvable letter for istradefylline (KW-6002) represents a major setback for Kyowa Hakko. The company had intended for the novel drug to gain approval as an adjunctive treatment in advanced Parkinson's disease. However, the FDA's decision is good news for Eisai, as it will reduce competition to its late-stage Parkinson's disease compound, E2007.

In the non-approvable letter, the FDA expressed concern as to whether the efficacy findings supported the clinical utility of KW-6002 (istradefylline) for the treatment of Parkinson's disease (PD). The agency requested an overall summary of non-clinical mineralization findings, as well as clinical pharmacology follow-up information as a Phase IV commitment. Kyowa Hakko has reported that it will work closely with the FDA and conduct a comprehensive discussion to determine a path forward for the drug.

Istradefylline (KW-6002), a selective adenosine A2a receptor antagonist, was intended to be used as an adjunctive therapy to levodopa/carbidopa for the treatment of idiopathic PD, in order to improve motor function in patients who experience 'wearing-off' effects. While most current drugs are unable to provide adequate improvement of OFF times (the premature loss benefit from a given dose of levodopa), KW-6002 appeared to have the potential to satisfy this key unmet need. The market for the treatment of 'wearing off' in advanced PD is considerably less competitive than that for the improvement of early PD. Furthermore, with a novel mechanism of action, KW-6002 would have benefited from first-to-market status of adenosine A2a receptor antagonists.

However, in view of disappointing clinical trial results, which include primary endpoint failures in two out of three Phase III trials, the FDA's issuing of a non-approvable letter for KW-6002 comes as little surprise to Datamonitor. These issues were raised in Datamonitor's conservative sales forecast for KW-6002 (prior to the FDA's decision), in which the drug was predicted to garner sales of only $58m in the seven major markets by 2016.

The non-approval letter issued by the FDA has opened a new window of opportunity for companies such as Eisai. Like Kyowa, Eisai is developing a drug for the potential treatment of OFF times in advanced PD, namely E-2007, an AMPA receptor antagonist. Since both products would have been targeting the same patient niche, the FDA's decision regarding Kyowa Hakko represents good news for Eisai in terms of reducing competition. With clinical trials to date suggesting impressive efficacy with few side effects, Datamonitor predicts E2007 to become the treatment of choice for prescribers when exploring options beyond the established PD treatment classes, with sales now expected to reach around $180m by 2016.

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Datamonitor's Stakeholder Insight: Parkinson's Disease

[edit] Sources

• Datamonitor