Seagen delivers a triple blow

A painful cut to guidance by one of the sector’s success stories is far from what biotech needs right now. But this is exactly what Seagen delivered, yesterday taking the axe to sales forecasts for all three of its top cancer drugs. The best the sellside could muster was that the company tends to guide conservatively, but this provided little comfort: Seagen's stock tanked 15% at the open today, slicing more than $3bn from its valuation. The biggest disappointment came with the Her2 kinase inhibitor Tukysa; guidance implies that sales might have already peaked after a mere two years on the market. The breast cancer drug is struggling to compete against astonishingly good data from Daiichi and Astrazeneca’s Enhertu, and the bull case for Tukysa – that strong CNS activity would continue to drive use in patients with brain metastases – is starting to feel like sheer optimism. Investors will have to hope that Seagen is laying out the worst-case scenario for 2022, but there are more risks to long-term numbers on the horizon. Several clinical readouts are looming that have the potential to take the company's products into new markets, and positive outcomes could not be more crucial.