FDA Approval of Voxzogo – An Unmet Medical Need?

Last week, the U.S. Food and Drug Administration announced approval of Voxzogo (vosoritide), a drug developed by BioMarin for the purpose of increasing growth in children with achondroplasia. The drug is approved for children five years of age and older who have achondroplasia and open epiphyses, and is administered by daily injection. Voxzogo was approved by the European Commission (EC) in August of this year and marketing authorization reviews are currently in process in Japan, Brazil, and Australia.

This drug was developed specifically to target the effects of the FGFR3 mutation that causes the fibroblast growth factor receptor 3 to be overly active in people with achondroplasia, which prevents normal bone growth. The FDA cited this trial as the reason for the approval: a year-long, double-blind randomized trial (RTC) that showed an increase in growth (a mean of 1.57cm per year) in participants who received the drug. While some suggest that other health complications may be ameliorated by the use of vosoritide, that is purely speculation at this point. The FDA approval was based on the trial’s primary endpoint, “change from baseline of annualized growth velocity.”

The study reports:

“This study is limited in that direct evaluation of the effect of vosoritide treatment on final adult height and how this relates to functionality, quality of life, and activities of daily living in people with achondroplasia cannot be evaluated at this time. In addition, whether treatment with vosoritide will ameliorate the medical complications associated with achondroplasia and decrease the need for surgical interventions is unknown.”

Vosoritide was given the Priority Review designation by the FDA meaning that the review will be completed within 6 months. According to the FDA website, the priority review designation exists to “direct overall attention and resources to the evaluation of applications for drugs that, if approved, would be significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious conditions when compared to standard applications.”

While a spokesperson from the FDA proclaims that this approval “fulfills an unmet medical need for more than 10,000 children in the United States”, this drug is controversial among people living with achondroplasia and other types of dwarfism. Many believe that the approval of this drug based on the ability to only increase growth is centered on corporate interests to bring a high-cost commercial drug to market without evidence that health outcomes are improved and that this approval represents deep prejudice against people of short stature. 

Vosoritide was approved under the Accelerated Approval Program, which arose from the 21st Century Cures Act, signed into law in 2016. This accelerated approval program lowers the bar for what evidence is required for FDA to approve drugs that treat serious conditions, and that fill an unmet medical need based on a surrogate endpoint. Proponents of this accelerated program say that it will help bring important treatments to patients faster. Many have expressed concern though, that these speedy approvals are putting patients at greater risk of harm given that the long term safety of these drugs is not known. With the accelerated approval process, the FDA can require additional post-approval studies. In the case of vosoritide, the approval is conditional on post-marketing study that will assess final adult height. This means that the primary justification for the drugs approval has always been increased height (not reduction in health concerns associated with achondroplasia) and that BioMarin will be able to profit off the sale of vosoritide for many years before we are certain that the drug actually increases final adult height.  

An important question up for debate here is whether a drug’s ability to increase the height of people with achondroplasia by 6-8 inches is meeting an unmet medical need. Considering the potential health effects secondary to the bone growth changes in achondroplasia such as sleep apnea and spinal compression, we won’t likely have the answer to that for some time.

Is short stature in and of itself a “serious condition” or “unmet medical need”? Maybe the answer to that question depends on whether you are viewing it through a medical model of disability lens or a social model. The medical model would hold that the condition of the person causes disability and that medicine should aim to “fix” the condition of the person. The social model would hold that it is systemic barriers in society and discriminatory views that cause disability – it is the condition of our society that needs fixing.

There is reasonable concern that the FDA’s enthusiastic support to celebrate the approval of this expensive drug to increase height can only further support discriminatory views that medical providers have had towards people with disabilities by validating that short stature in and of itself is a medical problem that needs a cure. 

The CEO of BioMarin, Jean-Jacques Bienaimé, seems to have a medical model perspective on achondroplasia judging by this quote: “It’s the difference between being able to drive a car or not, reaching stuff in closets, being able to take care of your hygiene. It would make a huge difference for those patients. There’s no question about it.”  

Daily injection of this drug is not necessary to allow people with achondroplasia to drive a car, reach the items they need, or take care of their own hygiene. Of course people with achondroplasia perform these activities all the time with assistive devices and inclusive design. This statement from BioMarin’s CEO may represent ignorance about the capabilities of someone with achondroplasia or, perhaps more likely, may be a misrepresentation to hype the importance of vosoritide.  

The stakes are high for BioMarin here. The drug is priced at $320,000 per year for the treatment, and the stock value surged with news of the FDA approval of what is being called the company’s new blockbuster product. FDA approval is linked to insurance coverage for drugs. Medicaid and Medicaid have very limited ability to decline drug coverage for FDA-approved drugs. Private insurers also must cover FDA approved drugs, although there may be more financial burden put on patients with cost-sharing arrangements. 

I have been thinking a lot about this FDA approval and the bigger system we are now in with so much interest (and money) in drug development for rare disease. There is a lot to be hopeful about for people living with rare conditions, but pervasive discriminatory views against disability in combination with massive corporate interest to rush therapeutics to market is of great concern. 

The use of vosoritide and similar drugs is likely to expand in the years to come. Studies are currently underway looking at vosoritide use in infants, and also the use of vosoritide for children with other genetic conditions that cause short stature. I would imagine fetal therapy trials may not be long in the future. The increase in therapeutics for genetic conditions will of course also fuel the diagnostic industry. I predict that as the approval of vosoritide therapies expands to younger ages, genetic testing companies will use this as a selling point for testing. Companies such as Natera and Baylor Genetics have been promoting a prenatal cfDNA test that screens for achondroplasia and other single gene conditions, and the companies have been trying to make the case that this test could result in better outcomes for families by learning about a diagnosis earlier. Having a treatment that could be started in infancy or even earlier could help make this case. 

When news of this FDA approval broke, I first learned about it on this twitter thread by Dr. Joseph Stromondo, professor of Bioethics and Disability Studies at San Diego State University. In it he says, “Did anyone ever doubt this outcome, though? There is never a moment any of us leaves our house that we aren’t greeted with ridicule and hostility. Our bodies are regarded as public spectacle just for existing in the world. How could this outcome be any different? Of course someone would find a way to profit off of these stigmas and the fears they produce in average height parents. This was inevitable. I think the more critical questions surround our response to the drug, as a community of dwarf adults and allies. What do we do now?” He concludes, “we need to find new ways to live with dwarf pride and help families see what is possible for their LP [Little People] kids. We need to come together and focus on creating a space that celebrates our lives and bodies in an otherwise hostile world.”

The development of the drug, and now the FDA approval of vosoritide has been controversial among people with achondroplasia. While some see the development of these drugs as an attack on their very existence, others are celebrating the approval with hope of the possibility of health benefits that result from use of the drug. 

Little People of America (LPA), a nonprofit support organization for people with dwarfism and their families, seems to be trying to navigate the differing viewpoints on drug development. From this FAQ on LPA and Pharmaceutical Company Engagement they state, “We have long celebrated dwarfism as a valuable contribution to human diversity. LPA also values diversity within our own community and respects the choices of its members regarding medical intervention. While LPA has never actively promoted medical research aimed at treating or curing dwarfism, LPA is not opposed to medical research if it holds the potential to improve quality of life by treating symptoms that can range from uncomfortable to lethal.” More recently in a position statement on the FDA approval of vosoritide, the LPA states that “they strongly believe that a focus on growth velocity is a search for a pharmaceutical solution for a societal problem. We want to reframe priorities in research to the most meaningful ones for our members, such as reducing spinal stenosis, sleep apnea, and the need for corrective surgeries, as well as supporting other improvements in quality of life.”

The availability of vosoritide will present parents with a decision that will be difficult for many. How do you make a choice about treatment when the potential for health benefit and the possibility of risk are impossible to quantify? While people who themselves have achondroplasia have differing views on vosoritide, it is fair to say that people with lived experience will likely have more background information from which to draw on to make a decision about whether to consent to treatment for their children with achondroplasia. While I can imagine there will be enormous pressure towards use of the treatment by healthcare providers, with most babies with achondroplasia being born to parents of typical stature, they may not even be presented with the consideration that declining the treatment as a reasonable option.

Pharmaceutical companies that profit from drug sales (and also those companies that make the tests that diagnose the conditions) have an interest in selling their products. That is the role of a company, and their primary duty is to their shareholders: to profit on products they produce. These priorities are not unexpected, and the current regulatory framework encourages it. It is expected that the information coming from BioMarin and their partners (who will also profit from this endeavor) will highlight the positive, hopeful aspects of the drug and downplay the uncertainty and potential risks. We can expect to see mass marketing of this drug that promises hope of more healthy futures for people with achondroplasia, even though we don’t yet have proof that this is the case. BioMarin projects $1 billion per year at its commercial peak in sales from vosoritide. Their chief commercial officer, Jeff Ajer recently stated that the company has teams “in place and well-prepared for what could be BioMarin’s largest brand yet.” It is likely that the perspectives and voices of those with concerns about vosoritide will be drowned out by the mountains of money that will be used to promote these drugs. 

As genetic counselors we are often the ones who will be sharing information about what life with a genetic condition could look like for a family who is hearing of a diagnosis for the first time. As new medications targeting genetic conditions are developed, we will be at the forefront of supporting our patients in navigating information about new treatments. With this privilege, we also have a tremendous responsibility. It is crucial that we are clear and honest about the limitations and unknowns. I hope all of us will take great care in evaluating the complexities of new and emerging treatments. I hope we will critically evaluate the sources of the information we are sharing with our patients. I hope we will listen to the critiques and concerns from people with lived experiences with the conditions that we are counseling our patients about. We will better serve all of our patients when we are prepared for discussions about the ethical debates surrounding treatment and people with disabilities as a historically marginalized population. 

As we consider the growing options families will have to face when considering whether or not to treat their children with new pharmaceuticals, for which the long term outcomes are still unknown, I hope that we will check our own biases and do our best to provide a nuanced assessment of the options and the concerns. And in balancing the messaging that may be coming from the big money that drives so much of this, I hope we will also seek out and share perspectives from people whose voices may be harder to hear amongst the hype.