Not even a full month since first being approved by the FDA for treatment of atopic dermatitis (AD), Sanofi and Regeneron’s burgeoning blockbuster dupilumab (Dupixent) is already being dragged to court again.
 
Sanofi and Regeneron pre-emptively sued Amgen back in March in an attempt to protect the drug, hoping a court decision would be a bulwark against a potential claim from Amgen that the mechanisms behind dupilumab were a violation of their intellectual property rights.
 
In previous efforts to develop an asthma medication, Amgen’s Immunex subsidiary received a ‘487 patent protecting the development of anti-interleukin-4 receptor antibodies. Dupilumab is a fully human monoclonal antibody directed against the body’s interleukin (IL)-4 and IL-13 receptors. Both are cytokines believed to play a major role in the manifestation of allergic diseases, and dupilumab is also undergoing trials in an ongoing effort to see it approved for the treatment of asthma as well.
 
The newest suit comes from Amgen, claiming patent infringement against Sanofi and Regeneron based on those biological mechanisms.
 
There is little argument against dupilumab's efficacy, with countless trials showing it to be a potent drug for those with moderate to severe AD. In the SOLO 1 and 2 trials, which tested more than 1300 patients whose AD was rated 3 (moderate) or 4 (severe) on the Investigator’s Global Assessment (IGA; 0-4 scale), scores dropped to 0 or 1 after 16 weeks in over 35% of all patients compared to 10% or less in placebo groups. Three-fourths of those studied saw reductions on the Eczema Area and Severity Index, with minimal side effects reported.
 
The drug was released with high expectations, projecting annual sales in the billions of dollars and believed to have the potential to “revolutionize” the treatment of AD. Dupilumab carries a hefty price tag of about $37,000 per year for treatment.

“There will be cheaper options to treat atopic dermatitis systemically,” the lead author of the SOLO studies told MD Magazine in a previous interview, “but they do not show the same level of effectiveness and are limited by significant side effects.”
 
“Not only has it shown efficacy in atopic dermatitis, but dupilumab also has shown efficacy in related atopic conditions such as asthma and nasal polyps," Regeneron’s Executive Director Bola Akinlade, MD, MBA, told MD Magazine.
 
Sanofi and Regeneron already find themselves in another patent battle with the complainant, Amgen, over PCSK9 inhibitors. In early January, a federal judge ruled that their alirocumab (Praluent) violated Amgen’s patents on evolocumab (Repatha). The decision is currently under review by a federal appeals court, but if upheld it would effectively leave Repatha as the only PCSK9 inhibitor legally authorized for domestic sale. Both drugs are cholesterol-lowering agents administered by injection.

That PCSK9 fight extends beyond the 3 companies involved: fellow pharma giants Pfizer, Ipsen, and Eli Lilly all filed amicus briefs siding with Sanofi and Regeneron, while AbbVie weighed in with one that vouched for strong patent protection, seemingly aligned with Amgen’s position. The squabble has been ongoing since 2014.
  
There is little indication that the fight will be over any time soon. Given that Sanofi and Regeneron are also pursuing the drug as a potential asthma treatment (and it has performed well already for that condition in trials), and Amgen initially received the IL-4 inhibitor patent in respect to asthma medications, the litigious tale of dupilumab seems to be at the very beginning.

It remains to be seen how it will intertwine with the fight over PCSK9 inhibitors, and to what end it may deprive patients access to effective new treatments.