J&J shares fall after court refuses to block Zytiga generics

Johnson & Johnson’s share price took a beating this week after the US appeals court declined its bid to stop sales of cheap generic versions of its blockbuster prostate cancer drug Zytiga.

The company's shares fell around 3% because of the court decision relating to Zytiga (abiraterone), which is the biggest-selling oncology drug from J&J’s pharma unit Janssen.

In the third quarter alone Zytiga generated US sales of $527 million and the company is fighting hard to prevent generic rivals reaching the market and disrupting revenues.

Thanks to an approval in early metastatic prostate cancer earlier this year, sales have been growing and were up 43% compared with the same quarter last year.

But Zytiga’s composition patent expired in 2016 and Reuters reported that a US appeals court on Wednesday declined a request by J&J for a temporary restraining order blocking sales of generics.

The US Court of Appeals for the Federal Circuit said it would not block Mylan and other companies from selling Zytiga generics while J&J seeks emergency relief at the US Supreme Court.

J&J is seeking to undo a lower court ruling from October that overturned a patent relating to Zytiga, which opened the door for generics.

The Federal Circuit court is due to hear J&J’s appeal of the lower court ruling on January 24.

J&J’s main rival in prostate cancer is Pfizer/Astellas Xtandi (enzalutamide), and unlike many other forms of tumour there is little trial evidence to show that checkpoint inhibitor immunotherapy drugs work in these tumours.

So far only one major trial has shown that an immunotherapy, Merck & Co.’s Keytruda, can work in metastatic prostate cancer, but the trial only tested patients who had previously been treated with Zytiga or Xtandi.

Other than generics the main threat to Zytiga and Xtandi looks to be from poly (ADP-ribose) polymerase, or PARP inhibitor class drugs.

At this year’s ESMO conference Clovis Oncology unveiled phase II data showing patients with BRCA1/2 mutated castration-resistant prostate cancer, responded to its Rubraca (rucaparib) PARP drug in second line.

The company is also trialling Rubraca in first line use, with Xtandi or Zytiga as a comparator.