Lazard Capital Markets raised its rating on Vivus Inc to "buy" from "neutral," saying the drugmaker's weight-loss pill was set to a big launch despite a potential patent dispute with Johnson & Johnson.

Vivus shares rose 8 percent in early morning trade.

Lazard's Joshua Schimmer became the second analyst -- after Cowen & Co's Simos Simeonidis -- to defend sales prospects of Qsymia, after short-seller Citron Research cast doubts on Vivus's ability to protect its weight-loss pill's patents.

Schimmer noted no threat to the launch of the weight-loss pill from a Johnson & Johnson patent on the use of one of its key ingredients, topiramate.

The analyst said the most likely scenario was a royalty stream payment to Johnson & Johnson to resolve the patent issue.

The brokerage also set a price target of $36 on the stock, citing the large patient population and the drug's safety profile.

Schimmer said he does not expect any hold-up in sales of the product from lack of reimbursement.

"More plans will reimburse for obesity drugs to manage the downstream costs associated with diabetes and other co-morbidities of obesity," he said in a note to clients.

Vivus shares, which fell as much as 15 percent the day Citron published its report, were up 6 percent at $22.61 on the Nasdaq.

(Reporting by Vidya P L Nathan in Bangalore; Editing by Don Sebastian)

(The story was filed to clarify that Lazard raised its rating, not price target)