Astrazeneca Scales Back Motavizumab

December 21, 2010 AstraZeneca scales back motavizumab

AstraZeneca scrapping motavizumab will not go down as the biggest surprise of the year, considering the product was twice rebuffed by US regulators as a new treatment to prevent respiratory syncytial virus (RSV). Although coming mere days after the FDA’s complete response to blood-thinner Brilinta, the Anglo-Swedish group is not having the happiest Christmas.

Astra will take a charge of $445m tied to the programme, which had very little expectation or market value attached. All is not completely lost, as a phase II study to show therapeutic, rather than preventative, benefit in very young, previously-healthy children hospitalised by RSV will complete early next year. There is no specific therapeutic available in this setting, according to Astra, but it now seems certain that motavizumab will not be inheriting the $1bn Synagis franchise.

Concerns

Motivizumab, previously known as Numax, and predecessor Synagis (palivizumab), were both acquired through Astra’s $15.6bn takeover of MedImmune. The acquisition has long been considered pricey, a view that will only be reinforced with this news. Synagis is likely to lose patent protection in 2015, and motavizumab was intended to take over and extend the franchise.

The FDA has issued two complete response letters to motavizumab’s application for approval, on safety grounds (Second motavizumab complete response could make AstraZeneca think twice, September 1, 2010). In the first instance it was found to induce severe and anaphylactic allergic reactions, particularly bad for a disease mainly affecting very young or premature children. The second response raised concerns about not testing the drug in a US demographic, while motavizumab failed to show significant non-inferiority to Synagis in reducing hospitalisations, and inducing more serious side effects than Synagis.

Non-prophylactic

A placebo-controlled phase II trial is still ongoing with motavizumab, due to complete in January. It is observing single doses given to previously-healthy children younger than one year old, currently in hospital due to RSV. As RSV normally induces only cold-like symptoms, this would be a group that had suffered a severe reaction to the infection, but had no underlying medical condition that would classify them as an “at-risk” population.

Synagis is not indicated for non-prophylactic use. AstraZeneca says it is not aware of any other RSV treatment that is purely therapeutic and thinks further study for motavizumab in this setting is therefore warranted.

Limited financial impact

However, this is a small population of probably quite pronounced cases, and the financial impact of any positive developments in this setting is likely to be fairly limited.

That Astra’s share price barely reacted to the news shows little market value for motavizumab remained. EvaluatePharma’s archived sales forecasts paints a stark picture of diminishing confidence. Pursuant to the FDA’s second rejection, consensus for 2016 global sales was $930m; a figure that has since been reduced to just $112m and will now be scrubbed completely.

Synagis sold nearly $800m worldwide last year. Although Astra reported for the first nine months this year a 29% decline in US sales on last year, the product remains its eighth biggest seller.

The end of motavizumab in RSV prevention may have come as no surprise, but setbacks like these, particularly ones that hurt the bottom line, are never welcome.