Nearly two-thirds of patients with Crohn’s perianal fistulas treated with the novel stem cell–based drug darvadstrocel achieved clinical remission and had significantly improved quality of life, according to new six-month data presented at the 2022 meeting of the European Crohn’s and Colitis Organisation.
Of the patients who received darvadstrocel (Takeda), which is not yet approved for use in the United States, 65% showed clinical remission at six months in both treatment cohorts, and 73% and 74% showed a clinical response.
As for safety, 9.3% of patients who received at least one vial of the drug experienced a serious adverse event, but there were no reports of ectopic tissue formation and no deaths.
These results offer hope to a group of patients who may suffer serious effects due to fistulas, experts said.
“Patients who experience perianal Crohn’s disease have significant impairment of their quality of life, as achieving closure of these fistulas is demanding,” said colorectal surgeon David Schwartzberg, MD, an assistant professor of surgery at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell Health, in Hempstead, N.Y.
“It’s a challenging group to treat, so for this patient population, a 65% remission with darvadstrocel is an encouraging outcome,” said Dr. Schwartzberg, who was not involved in the study.
Shrinivas Bishu, MD, an assistant professor at the Crohn’s and Colitis Program at the University of Michigan, in Ann Arbor, called this six-month response rate “highly promising,” especially when you consider that most patients had no change in Crohn’s disease activity from baseline. “This product is essentially able to improve fistulas and response rates, even while patients had internal active IBD,” Dr. Bishu, who was also not involved in the research, told Gastroenterology & Endoscopy News.
In the past, fistulas only healed after the luminal disease was resolved. But darvadstrocel appears to work by an independent mechanism; it effectively de-links IBD activity and complex Crohn’s perianal fistulas, he said.
Hope for a Complex Problem
Most of the patients included in this analysis, an observational post-marketing registry called INSPIRE (poster 603), had complex Crohn’s perianal fistulas for which other standard treatments had failed.
“There are plenty of treatments, but nothing so far has been very successful. That’s why we are pretty happy with these results,” said lead investigator Oded Zmora, MD, a colorectal surgeon and professor in the Department of Surgery at Shamir Medical Center, in Tel Aviv, Israel. Plus, “stem cells are pretty easy to install. It’s a pretty simple surgery, with low risk.”
The researchers compared outcomes in two groups. All were from countries where darvadstrocel is approved, and their data were entered prospectively into a database over at least six months.
The first group included only patients who received four vials of the drug according to a specific surgical protocol:
- They had no abscesses and had well-identified internal and external openings.
- Patients had a vigorous curettage performed and internal opening closed, with no superficial fistula tract.
- Four vials of darvadstrocel were injected: two vials of the drug at the internal orifice and two vials alongside the fistula tract.
The second group they analyzed included everyone who received at least one vial of the treatment. “Because it’s an already approved treatment, the surgeon can use stem cells and perform the procedure in the way he or she judges to be best,” Dr. Zmora said. And based on the results, “the protocol did not matter,” Dr. Zmora said. “They had the same success rate.” Both achieved a 65% clinical remission rate, so Dr. Zmora advises providers to use their best judgment in the application of this treatment.
Although this study looked at a short follow-up period in a small group of patients, Dr. Zmora and his colleagues plan to follow these patients for three years after treatment. More data over a longer time period are critical to better “understand the role of stem cells in these patients who are really suffering,” he said.
To providers using darvadstrocel—the drug is approved in Japan, Israel and Europe—Dr. Zmora urges them to include their patients’ data in the database. “That’s the only way to figure out what we are doing right, what we are doing wrong and to define the best way to treat these patients.”
Dr. Zmora reported financial relationships with Takeda, including acting as steering committee member on the INSPIRE registry.
Drs. Bishu and Schwartzberg reported no relevant financial disclosures.