Over the years since Luke’s diagnosis, our supporters will have seen me post fervently in favour of approval of Exondys 51 (previously Eteplirsen). You’ll have had me ask you to sign petitions, seen me post patient stories and even fly to Washington D.C. to help our fellow American patient advocates campaign the Food & Drug Administration (FDA) for approval. And just a few weeks ago you celebrated with me, when after a delay of 4 months, the FDA finally agreed to grant Accelerated Approval for Exondys51.
But I know that some of you have been wondering why we are so excited over the approval of a drug which is not yet available here and which will not help my son Luke or my cousin Brian Og. And the reasons relate much more to the bigger picture and the doors that approval of Exondys51 has opened both is terms of the drug development process and in providing real hope to families like mine.
In the grand scheme of things FDA approval of Exondys 51 has paved a clear pathway forward for the approval of personalised medicines to treat small subsets of patients with DMD. While Exondys51 itself will only treat around 13% of boys with Duchenne, the technology it uses, exon skipping, can be used to treat around 80% of boys by slightly tweaking the formula to target a different mutation. Sarepta Therapeutics, who make the drug have a pipe line of follow on exons, and the next in line will help Luke and Brian Og, with the trials currently recruiting in the U.S. The hope is that approval of Exondys 51 has created a more effective and efficient pathway to approval for the follow on exons, bringing real and tangible hope to a generation of boys and their families. It has shown that drug regulators are open to the approval of drugs for small patient populations based on smaller than normal trial populations when the drug is safe, and is reasonably likely to have a clinical benefit.
While FDA approval only makes the drug available in the US, patient advocates and clinicians are hopeful that approval by the FDA places the drug in a more favourable position for approval by the European Medicines Agency (EMA), and patients and charities in Europe can now lobby Sarepta Therapeutics to quickly lodge their New Drug Application to the EMA and urge the EMA to follow the FDA’s lead in providing a clearly safe and effective drug to children with a life limiting condition for whom time is of the essence.
The long and turbulent wait for approval of Exondys 51 had captured the attention of investors and Bio Pharma companies across the world and its success will likely lead to new and significant investment in the Duchenne drug development arena, not just for exon skipping technologies but for other promising therapies, which may have the potential to treat all children with Duchenne regardless of their specific Duchenne causing mutation. This can only help to speed up the drug development process and contribute to saving the lives of children and young adults affected by Duchenne.
In my opinion Exondys 51 was approved, in large part, due to the patient voice which was backed up by science and the testimony of expert clinicians, scientists and doctors. Families and parent led organisatons in the States were instrumental in advocating for the drug’s approval and even managed to organise the largest gathering of Duchenne families in history to attend the Advisory Committee Meeting in April. Such successes highlight the importance and power of the patient voice and has motivated families and charities in Europe to follow their example. They have taught us that our voice matters and that when we come together we can create miracles.
For me personally the approval of Exondys 51 is a monumental milestone in the life that has descended over 3 generations of my family. For 50 years we have watched young men in our family succumb to the devastating consequences of Duchenne with no viable treatment options. Now, for the first time ever, we have a drug that has the potential to pave the way forward for my son, my cousin and future generations of our family. It has created the possibility that my son’s life may be spared, that we may keep him on his feet longer delaying the inevitable devastating decline that he will otherwise face.
Approval of Exondys51 represents the first battle that we have won in what has been, and will continue to be, a long war against Duchenne. Neither Exondys51 nor any of the follow on exons will cure Duchenne. They will simply help to delay the progression of the condition, keeping boys on their feet longer – maintaining independence, and staving off further complications like scoliosis, and respiratory & cardiac complications – prolonging life for patients. In reality, it will take a combination of therapies to halt progression in the long term, but approval of Exondys 51 has created the possibility of more efficient drug development and approval processes for other potential therapies and has presented opportunities for greater collaboration among the multitude of pharma companies, who will now feel that the Duchenne drug development industry in worth investing in.
Approval of Exondys51 has heightened the resolve of the Duchenne community to fight tooth and nail to stop Duchenne.