JP Morgan 2019 – Alnylam turns Onpattro frown upside-down

Alnylam appears to have turned its Onpattro launch around, but is adamant that investors should have been more patient all along.

Launching a drug can be difficult; just ask Alnylam. The company has been hammered on the stock markets since the approval of its amyloidosis therapy Onpattro, as disappointing initial sales figures compounded fears of commercial misstep. 

But much improved fourth-quarter revenues, pre-announced at the JP Morgan conference on Monday, have put the group on more solid ground just as it prepares to face its next test – competition from Pfizer’s tafamidis.

Alnylam investors sent the group’s stock up 9% on the back of the announcement, which put fourth-quarter Onpattro sales at $11-12m, well ahead of analyst expectations. The new figures are also a far cry from the $0.5m that Onpattro registered in the third quarter, a sum that spurred another exodus from the stock.

However, Alnylam’s president, Barry Greene, told Vantage: “The Onpattro sales were never disappointing, there was just some confusion.” He noted that the third quarter had only included seven weeks of Onpattro sales.

He would not give any guidance for 2019 Onpattro revenues, saying it was too early in the launch; Stifel analysts noted that sell-side expectations currently range from $85m to $120m.

Fearsome competitor

Competition will soon come in the form of Pfizer's tafamidis, due an FDA approval decision by July in patients with transthyretin amyloid cardiomyopathy; the project has shown promise in both inherited and wild-type disease.

Onpattro is indicated for a different disease subtype, polyneuropathy in adults with hereditary transthyretin amyloidosis.

Mr Greene was upbeat about Onpattro’s chances, even with such a fearsome competitor looming. He said: “If it’s a wild-type patient tafamidis is the perfect drug for them. For a hereditary patient with polyneuropathy Onpattro is clearly the best choice.”

If it seems likely that Onpattro will dominate the polyneuropathy segment, with tafamidis picking up cardiomyopathy patients, how the market will split in those with a mixed phenotype is less clear.

Pfizer today refused to give any details about tafamidis’s potential price, which could be a factor in doctors’ decision-making.

Son of Onpattro

Alnylam has a subcutaneous Onpattro follow-on, ALN-TTRsc02 – also known as vutrisiran – which it might choose to test head-to-head against tafamidis in patients with cardiomyopathy.

The company is still weighing up the design of that trial, Helios-B, Mr Greene said: “We need to understand what Pfizer is doing with dose and formulation.” Tafamidis is approved in Europe for polyneuropathy at a 20mg dose, but the recent Attr-act trial in cardiomyopathy tested both 20mg and 80mg (ESC 2018 – Pfizer impresses with tafamidis, but amyloidosis battle goes on, August 27, 2018).

The situation should become clearer once Alnylam starts Helios-B later this year. The group has a big year ahead, with pivotal data due from three more projects: givosiran, lumasiran and the Medicines Company-partnered asset inclisiran.

Success is far from guaranteed, but at least Alnylam has started to improve confidence in its ability to launch these projects, if any get that far.

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