A Chiesi survey has found widespread unmet needs among Fabry disease patients taking drugs such as Sanofi’s Fabrazyme, pointing to how the Italian drugmaker can muscle in on the market.
Chiesi won FDA approval for the Fabry disease drug Elfabrio last year. Patients already had access to Sanofi’s old stager Fabrazyme and Amicus Therapeutics' more recently approved oral challenger Galafold. But Chiesi identified a persistent unmet need, leading it to pay Protalix BioTherapeutics $50 million upfront plus $45 million to cover development costs to secure the rights to a Fabry prospect.
Seeking to understand the unmet need, Chiesi and its collaborators surveyed 280 adults in the U.S. and Canada about their experience of living with Fabry. The researchers recently published the findings in the Orphanet Journal of Rare Diseases.
Most, 84%, of the respondents were taking an enzyme replacement therapy (ERT) such as Fabrazyme or Takeda’s Replagal. Eleven percent of respondents were taking chaperone therapy, namely Galafold. Most of the people had unmet needs despite being on one of the approved treatments.
The most common symptoms were low energy, tingling and pain in the hands or feet. Between 60% and 72% of respondents had those symptoms. More than half of the Fabry patients had ringing in their ears or hearing loss, general body pains or stomach pains. For 51% of respondents, the symptoms were hard to control or bothersome.
Symptoms temporarily worsened between infusions in around half of respondents. However, only 48% of those patients reported the worsening to their physicians. In most cases, the doctor neither changed the patient’s treatment nor prescribed them a medicine to manage the symptoms.
The survey results speak to why Chiesi sees a need for Elfabrio. Chiesi’s ERT performed similarly to Fabrazyme on the primary endpoint in a head-to-head phase 3 clinical trial. Elfabrio has a longer half-life, though, suggesting symptoms may be less likely to worsen between infusions, and its PEGylated design and other elements could improve tolerability and lower the rate of infusion-related reactions.
Chiesi posted sales of 3 billion euros ($3.2 billion) in 2023, supported by 65% growth at the rare disease unit that sells Elfabrio. The statement lacks details of Elfabrio sales. Protalix generated $17.5 million from sales of Elfabrio to Chiesi last year.