Fibrogen and Carpmaels defend anaemia drug in UK appeal

US pharmaceutical manufacturer Fibrogen has partially won an appeal in a dispute with Akebia concerning an anaemia drug. The six patents in question all relate to a medication used in the treatment of anaemia, with the patents forming two families. Family A consists of EP 14 63 823, EP 2 289 531 and EP 22 98 301, while Family B consists of EP 16 33 333, EP 23 22 153 and EP 23 22 155.

Family A patents’ claims all concern a class of compounds defined for use in the treatment of chronic kidney disease (CKD). The claims of family B patents concern the same compounds, but for the treatment of anaemia of chronic disease (ACD).

At the end of August, Fibrogen received approval from the European Medical Agency (EMA) for the drug Evrenzo. Its active ingredient roxadustat is an HIF-prolyl hydroxylase inhibitor intended for the treatment of CKD. Now the UK Court of Appeal has released a judgment in favour of Fibrogen.

Fear of infringement

Akebia aims to launch its own anaemia drug containing the HIF-prolyl hydroxylase inhibitor vadadustat. In 2018, Akebia and its licence partner Otsuka filed revocation proceedings against Fibrogen in order to pave the way for their product. The parties argued Fibrogen’s family A patents, and most of its family B patents, were invalid. This is due to lack of inventive step and insufficiency.

Astellas, the Fibrogen licensee in the UK, counter-claimed for infringement regarding the family A patents. In addition, Fibrogen brought a ‘quia timet’ infringement case concerning the family B patents.

Currently, the clinical trials for Akebia’s vadadustat and its draft marketing authorisation are aimed at treating CKD. Nevertheless, Fibrogen fears Akebia could market its compound in a way that infringes the family B patents and their use for treating ACD.

UK High Court rulings partially overturned

In April 2020, the UK High Court found EP 823, EP 301, EP 333, EP 153 and EP 155 invalid for insufficiency. The court also ruled one patent, EP 531, valid on the grounds of obviousness, but not infringed if Akebia launches its own product.

The UK Court of Appeal has now partially overturned the first-instance decision handed down by Richard Arnold (case IDs: A3/2020/0895 and A3/2020/0893). Here, Colin Birss ruled the family A patents, namely EP 823, as valid. According to the court, if Akebia were to launch an anaemia drug containing vadadustat for the treatment of CKD, this would infringe Fibrogen’s patents.

The court also dismissed the appeal on obviousness of the family B patents. Therefore, although the conclusion on sufficiency also applies to those patents, they remain invalid for obviousness.

Pharma specialists

Akebia and Otsuka, Fibrogen and Astellas are all innovators. Thus, all parties turned to firms well-versed in litigation for innovators in complex pharmaceutical cases. Their legal teams have advised on the dispute from the beginning.

For Fibrogen
3 New Square: Thomas Mitcheson, Joe Delaney, Thomas Lunt
Carpmaels & Ransford (London): David Wilson, Jennifer Antcliff (partners); Richard Newell, Paul Kaufman (patent attorneys); associates: Craig Lumb, Aled Richards-Jones

For Akebia and Otsuka
11 South Square: Piers Acland, Iain Purvis, Anna Edwards-Stuart
Hogan Lovells (London): Stephen Bennett, Dan Brook (partners); associates: Stella Wong, Helen Poulson

For Astellas
3 New Square: Justin Turner, Michael Conway, Kathryn Pickard
Potter Clarkson: Nick McDonald, Oliver Laing (solicitors); Tony Proctor, David Carling (patent attorneys) (all partners)

Court of Appeal, London
Colin Birss (presiding judge), Stephen Phillips, Christopher Floyd