The first clinical results in ALS from the private biotech QurAlis arrived Monday with a handful of questions.
The startup believes the biomarker data from the Phase 1/2 study are strong enough to move the drug, QRL-201, to a pivotal trial. But the experiment failed to reach a statistically significant improvement over placebo on a clinical measurement that has been the standard for ALS trials.
Any path to approval — which the company thinks it can pursue with a pivotal trial it’s planning — will need to answer more definitively whether QRL-201’s impact on patient biology can translate to helping patients on real-world measures.
In the data released Monday, the experimental drug increased by two-fold the levels of a target protein called STMN2 that’s thought to be involved in the vast majority of ALS cases. But in a rating scale of ALS symptoms typically used as a primary endpoint in pivotal studies, the difference between QRL-201 and placebo wasn’t significant.
Due to the nuances of how ALS progresses in different individuals, and the disease’s universally fatal nature, those data may be enough to widen testing and make another try at the clinical endpoints. ALS can start with swallowing problems in some patients, and with muscle weakness in others. It can progress quickly, or take months for patients to decline. These factors make clinical assessments more difficult.
QurAlis hopes to start that study next year and enroll somewhere between 150 and 300 patients, CEO Kasper Roet told
Endpoints News
in an interview.
“It’s pretty exciting,” Merit Cudkowicz, director of the Healey Center for ALS at Massachusetts General Hospital and an advisor to the company, told Endpoints. “I don’t think it’s enough for approval right now, and that’s for the FDA. But you certainly want to go to the next trial as fast as you can.”
Finding a cure for ALS has long been seen as a holy grail of drug development. The disease was discovered in the 1860s, then thrust into the American public’s awareness in 1939, when baseball star Lou Gehrig — who was famous for his durability, earning the nickname “The Iron Horse” — discussed his diagnosis in his retirement speech.
Since then, only a handful of drugs have been approved for the disease, and they only modestly help patients. Most recently, in 2023, Biogen and Ionis got approval for Qalsody, a drug for patients with a specific genetic version of ALS representing about 1% to 2% of patients. Roet said QurAlis used Biogen’s development plan as a starting point, since both drugs are antisense oligonucleotides that target the underlying disease biology.
But QRL-201 is designed for “sporadic” ALS, which doesn’t have a known genetic cause. About 90% of all ALS patients have sporadic disease. The drug goes after STMN2, which is involved in the buildup of another protein, TDP-43. In ALS, about 97% of patients have toxic buildups of TDP-43, and QurAlis hopes that by targeting STMN2, patients won’t progress as quickly.
“Measuring STMN2 levels is measuring something that we think is really able to counteract the disease itself,” Roet said.
The clinical measurement for ALS trials is called the revised ALS functional rating scale, or ALSFRS-R. It is considered a gold standard for such studies, though some — including the scale’s creator — have
called for an upgrade
.
Patients are evaluated on 12 different functional measurements, each on a five-point scale from 0 to 4. A healthy individual would receive a 4, for a maximum total of 48 points. As ALS patients lose the ability to walk, breathe and eat independently, their scores fall.
In QurAlis’ study, QRL-201 showed an “encouraging trend” in slowing patients’ declines on the scale. After 28 weeks, patients on QRL-201 saw their ALSFRS-R scores decline by 3.5 points, compared with 6.3 points in the placebo group. But the difference between groups wasn’t statistically significant.
But when patients were sorted into three groups by how quickly their ALS progressed — slow, medium and fast progressors — QurAlis found a silver lining. QRL-201 induced a statistically significant difference when the fastest progressors were excluded.
Now, the company will have to design its trial for success. In Biogen and Ionis’ Qalsody trials, fast progressors also performed worse, and the trial failed on a six-month timeline. But after collecting more data, they won approval from the FDA based on a biomarker. Many patients, though, don’t want to be on a placebo for long, given the disease’s 100% fatality rate, Cudkowicz said.
“I like to have hope that drugs will work in everybody,” Cudkowicz said. “You only have one shot, really, in a good trial.”
For QurAlis’ pivotal study, Cudkowicz said researchers could maintain the same inclusion criteria and use the ALSFRS-R as the primary endpoint, while also providing an early readout of the drug’s impact on biomarkers. A bigger trial could also split patients into different groups based on how quickly they are worsening.
All of that will still have to come after discussions with the FDA, Roet said.
“You want to set yourself up for success,” Roet said. “This strategy actually fits perfectly within what people think is the future of ALS clinical trials.”
Editor’s note: This article has been updated to correct that QRL-201 increased levels of STMN2 by two-fold, not halved levels of STMN2.