Safety worries hit Fibrogen as huge tests approach

It is a sign of these hair-trigger times that even a hint of a misstep can cause a stock to tumble. Take Fibrogen, which dropped 11% yesterday and slipped further today on whispers of safety signals from its late-stage anaemia project, roxadustat. These emerged in presentations over the weekend of two phase III trials conducted in China; both showed roxadustat patients experiencing higher rates of hyperkalemia and metabolic acidosis, while one (n=304) hinted at an imbalance of cardiovascular events. Supportive sellside analysts brushed off the relevance of these findings, pointing out that these were two small trials. This is certainly true although confirmation of any cardiac signal would be a huge blow; much of the hope for roxadustat is that it will show superior cardiovascular safety to existing anaemia treatments, namely the EPO class. A robust answer will come soon: seven pivotal studies are slated to start reporting in the coming weeks, culminating in a pooled analysis early next year that specifically looks at cardiac events. An earlier test could come sooner in China, where regulators are due to rule on approval before the end of the year. Good news all round is needed to lift Fibrogen shares, which are currently trading around 15-month lows.

The global outlook for roxadustat
  Annual sales ($m)  
Company 2019e 2021e 2024e Main markets
Astrazeneca 113 485 1,043 US, China (co-promotion with Fibrogen)
Astellas 51 307 681 Japan, Europe, CIS.
Fibrogen 30 112 265 China co-promotion with Astrazeneca
Total 194 905 1,990  
Source: EvaluatePharma.

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