For the first time, the FDA has approved a treatment for recurrent respiratory papillomatosis (RRP), a rare, chronic disease that causes benign tumors, most commonly in the voice box, and can force some patients to endure hundreds of surgeries to remove the growths.

Making the grade is Precigen’s Papzimeos (zopapogene imadenovec-drba), a first-of-its-kind non-replicating adenoviral vector-based immunotherapy, which can eliminate the need for repeated surgical interventions.

Papzimeos, which is administered by a subcutaneous injection, triggers an immune response against cells infected with human papillomavirus (HPV) types 6 and 11, which cause RRP. Four shots are administered over the course of three months, providing patients with what is expected to be long-term protection against the emergence of the tumors, also called papillomas.

The approval brings relief to patients long resigned to a lifetime of surgeries—for some, as many as a dozen per year.

That was the case with Kim McClellan, the 59-year-old president of the RRP Foundation, who has withstood more than 250 surgeries since she was diagnosed with the disorder at age 5.

“It cannot be underscored enough what an historic moment it is with the approval of Papzimeos for this patient population,” Precigen CEO Helen Sabzevari, Ph.D., said in an interview with Fierce. “It has changed the paradigm for treatment of these patients.”

The FDA nod, which came nearly two weeks ahead of the agency's target decision date, applies to adult patients with RRP. Despite the agency signing off on Precigen’s submission under an accelerated pathway nine months ago, this is a full approval and does not require a confirmatory trial. 

“Randomized trials are not always needed to approve medical products and this approval is proof of that philosophy,” Vinay Prasad, M.D., the director of the FDA’s Center for Biologics Evaluation and Research, said in a release. “The FDA will always demand the correct clinical study for the specific medical product and disease. Our requirements for products given to tens of millions of healthy people will be different than products given to at most hundreds or thousands of patients with unique diseases.”

The virus is spread through sexual contact or when a mother passes it on to her baby during childbirth. RRP symptoms, which include voice changes, breathing difficulties and airway obstruction, are often more severe in children. Although rare, the condition can transform into malignant cancer and be fatal.

The disorder was identified more than a century ago, with roughly 1,000 new pediatric patients diagnosed annually. The incidence of RRP is roughly two in every 100,000 people.

Doctors who have performed the RRP surgeries have described it to Sabzevari as like tending to a lawn.

“It’s like grass, you mow it and then it returns,” Sabzevari said. “When patients start having problems speaking or breathing, that’s when they go back to their physicians and ask for treatment.”

Sabzevari added that a recent study showed that 70% of patients have already sustained irreversible damage to their vocal cords or trachea by their fifth surgery.

The approval was backed by a trial of adult patients with RRP who require at least three surgeries per year. Of the 35 patients in the study, 51% achieved a complete response, which was defined as not needing a surgical procedure in the 12 months following treatment.

Follow-up data showed that 15 of the 18 patients who achieved a complete response maintained it through two years. Patients in the trial averaged 0.5 surgeries in the year following treatment.

In a Monday conference call, Precigen will reveal what it will charge for the treatment.

Through claims data and electronic health records, the company has identified 27,000 adult RRP patients in the U.S., according to Chief Commercial Officer Phil Tennant, a veteran of Astellas, Bristol Myers Squibb and AstraZeneca, who was hired a year ago to lead the launch of Papzimeos. Precigen also has enlisted Chicago-based Eversana to support its commercialization.

Precigen originally formed as a subsidiary of Intrexon, which was founded in 1998. Intrexon debuted on the public markets in 2013 and changed its name to Precigen in 2020.

The company touts its AdenoVerse immunotherapy platform, which employs gorilla adenovectors, as enabling the biotech to "engineer cutting-edge therapies to treat complex diseases."

Precigen's stock price jumped nearly 50% early Friday in the wake of the approval.