Developer of the recently-approved Qsymia weight-loss drug, Vivus, (NASDAQ:VVUS) is down 7% this morning after a downgrade from Jefferies; the analyst gave Vivus a new price target of $16, much lower than the Street’s average rating of $30. Jefferies cited generic competition as a major deterrent to Qsymia revenue and slashed peak sales expectations from $3.2B to $1.2B. Doctors may be unwilling to prescribe the higher-cost Qsymia when two generic drugs – Qsymia is a more complex combination of the two – could be prescribed in tandem for significantly less. Insurance companies may resist the more expensive branded product with an alternative option available. Vivus argues that a combination prescription will be a liability for providers, while Jefferies says that the liability risk is overstated. Investors will have little information on which to base analysis until sales figures emerge.