Kynamro: Rare cholesterol disease treatment is a win for Sanofi's Genzyme

Kynamro
Project name: mipomersen sodium
Disease: Homozygous familial hypercholesterolemia
Peak sales estimate: $400 million
Approved: Jan. 29
Companies: Sanofi and Isis

The Scoop:
The approval of this drug, one of the first of 2013, was always uncertain, and when it came, it came with limitations. Isis ($ISIS) CEO Stanley Crooke had suggested Kynamro could be a successor to Lipitor, the all-time best-selling drug and the go-to drug for treating high cholesterol. The FDA didn't see it in quite the same light.

The agency approved Kynamro only for treating the very rare but sometimes fatal genetic condition homozygous familial hypercholesterolemia (HoFH). Kynamro lowers the super-high LDL that HoFH presents, but the drug comes with increased risks for cancer and liver side effects. Patients with this condition have limited therapeutic options, but drug reviewers noted a number of deaths and serious adverse events in the clinical studies of mipomersen. With that in mind, the FDA required four postmarketing studies and wants the developers to carefully track the long-term safety of the drug. It also mandated a Risk Evaluation and Mitigation Strategy (REMS), including certification that prescribers and pharmacies that sell it have been trained about those risks. The REMS program is designed to protect the larger hypercholesterolemic patient population from the drug.

It is a win for Sanofi's ($SNY) Genzyme--which Isis brought in several years ago to help with development of the drug--as well as for Isis. When French drugmaker Sanofi paid the handsome price of $20.1 billion for Genzyme in 2011, it said the payoff would come as it provided Sanofi with many of the new drugs it expects to propel future earnings. Given Sanofi's troubled financial picture these days, any new revenue is welcome.

Isis, meanwhile, got a $25 million milestone with approval and legitimacy for the science behind Kynamro. The drug reduces LDL cholesterol by inhibiting the production of apo B, a protein that provides the structural core for atherogenic lipids. The FDA review noted that the average 25% reduction in LDL-C is significant. But it also noted the dropout rate in the study and that there was a wide range of individual responses behind that group figure.

Only about one in a million people have the genetic disorder HoFH, which produces such elevated levels of LDL that they can trigger fatal cardiovascular conditions. That will keep peak sales in check. But its rarity is the reason Sanofi is able to set a six-figure price tag on the treatment, $176,000 before discounts. It is, however, not without competition. Aegerion Pharmaceuticals ($AEGR) treatment, Juxtapid, was approved in December 2012. It runs a steeper $235,000 to $295,000 a year, depending on the patient, but Aegerion's drug also got a more positive response than Kynamro by FDA reviewers. It is too early to see how those competing factors will play out and pay out in the market. -- Eric Palmer (email | Twitter)

For more:
FDA hands Sanofi, Isis an approval for HoFH drug Kynamro
FDA approves Aegerion's lomitapide for rare cases of HoFH
Genzyme's mipomersen wins key FDA panel vote for rare cases of HoFH
FDA frets over safety of Genzyme's rival drug for rare cholesterol disease
Sanofi CEO: Thanks to Genzyme, investors take us seriously

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Kynamro: Rare cholesterol disease treatment is a win for Sanofi's Genzyme