Dyax finally wins US approval for HAE treatment Kalbitor

Dyax’s share price this morning no doubt reflected the jumping for joy that must have been going on at the company’s headquarters last night when news of FDA approval for Kalbitor (ecallantide or DX-88) arrived.

The company has been struggling to win approval for several years now and once thought the drug could be on the market in 2007; requests for further trials delayed progress and the company lost a partner in the shape of Genzyme along the way. However, Kalbitor will still be the first small molecule drug approved to treat acute attacks of hereditary angiodema (HAE) in the US, and as such the 22% leap in Dyax’s share price this morning, to a 14-month high, certainly looks justified.

CSL’s Berinert P and ViroPharma’s Cinryze are both already on the market in the US, approved respectively to treat and prevent attacks of the swelling disorder. However, these are transfusion products, and as such Dyax’s subcutaneous injection should be able to compete effectively.

The market is certainly small, there are only thought to be 6,500 sufferers in the US, so competition will certainly be intense. However, as well as convenience another aspect that should help Dyax is that Kalbitor is the only drug approved to treat all symptoms of HAE, which can cause swelling in the throat, face, neck and abdomen. Importantly the label specified laryngeal attacks, which are life threatening.

Premium price

All this should mean Dyax can command a premium price to the CSL and ViroPharma products. Consensus for sales in 2014 currently sits at $128m, with analysts now awaiting news on the pricing of the product to adjust their models.

The table below shows how forecasts stand for the for main HAE products at the moment. Analysts covering CSL do not break out Berinert P, as the product is fairly insignificant for the company as a whole, and it remains to be seen if CSL itself will disclose sales figures.

Dyax is still looking for a European partner for Kalbitor, where it will come up against another small molecule, Firazyr, sold by Shire. The identity of the partner will be revealing in terms of how these two products will compete with each other.

Still, Firazyr is has not yet been filed in the US, so Kalbitor will have this market to itself for a while yet.

Hereditary angioedema market Annual Sales WW - Sales
Product Company Pharmacological Class 2009 2010 2011 2012 2013 2014
Cinryze ViroPharma C1 esterase inhibitor  96  162  205  244  274  303
Firazyr Shire Bradykinin B2 antagonist  10  37  81  131  177  220
Kalbitor Dyax Kallikrein inhibitor  -  27  62  87  108  128
Berinert P CSL C1 esterase inhibitor  -  -  -  -  -  -
Total  107  226  348  462  558  651

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