Regulators in the USA have made it easier for Vivus to sell its diet pill Qsymia but the firm is again being urged to sign a partnering deal with big pharma if the drug is to be a blockbuster.

In September, Qsymia (phentermine/topiramate) became the first new medication to be approved in the USA in 13 years for obesity but its uptake has been slow not least because it has only been sold through home delivery pharmacy. That was part of the risk evaluation and mitigation strategy linked to approval by the US Food and Drug Administration but now the REMS has been modified, which will make Qsymia available through certified retail pharmacies.

Vivus president Peter Tam said the move will simplify prescribing and dispensing, thus "resolving the challenges associated with the mail-order-only system". He added that "our goal over the next three months is to ensure availability of Qsymia in thousands of certified retail pharmacies nationwide", noting that the REMS modification "is a key accomplishment in removing a major barrier that has hindered the initial acceptance of Qsymia into everyday medical practice".

Good news then for Vivus but analysts are still concerned. Simos Simeonidis at Cowen & Co issued a research note saying the REMS modification is a long-term positive but "we don't expect to see a near or medium-term impact on the stock, since it will be a minimum of two quarters before a significant impact of this change is felt on scripts".

Furthermore, he believes that "it is not by itself enough to make up for the biggest issue for Qsymia, which is…the lack of a significant sales and marketing detail effort targeting primary care prescribers". __Mr Simeonidis argues that "Qsymia can become a significant drug,  however, we have assumed that this only happens with the help of a big pharma partner". He added that "we don't believe that this level of sales is achievable by any small biotech/spec pharma company's salesforce". Vivus has about 150 reps.

The analyst concluded by saying that "we view this as simply a matter of scale". Vivus is also under pressure from shareholders, notably First Manhattan, which owns 9.1% which last week unveiled plans to get six nominees onto the board at the firm's annual meeting in June and Mr Simeonidis said such moves  "should help guide the company in that direction".