This week, Arena Pharmaceuticals
In the EU, companies have had a much easier time gaining approval for drugs; the two agencies are usually looking at the exact same data, so the only logical explanation is that the European Medicines Agency has a lower threshold for risk-benefit analysis than the FDA.
Even with the seemingly easier pathway to approval, there's still a big risk that the EMA doesn't approve lorcaserin or the other obesity drugs. The EMA seems to be taking just as hard a stance as the FDA when it comes to heart issues with obesity drugs. In fact, Abbott Labs'
If the obesity drugs were able to get on the market, they could have an easier time getting to patients, though. Obesity is a long-term health concern, which means helping someone shed pounds now only helps a U.S. insurer if the patient keeps the same insurance for an extended period of time. Since people switch insurance frequently, there's less incentive to cover obesity drugs or assign them a low-tier co-pay to encourage their use.
The European health-care system, on the other hand, is fairly holistic since there's often only one government insurer covering most of the patients. The European health-care systems tend to be fairly price conscious, but they're also forward-thinking; spending money now on obesity drugs could save a lifetime of diabetes or heart drugs in the future.
If you're going to include potential EU sales in your valuation model, I'd suggest applying a high risk adjustment, and discount them by at least 50% (more if you're trying to be more conservative). Without an advisory panel system like in the U.S., investors won't get much insight into what the agency is thinking until the decision is made.