Cytokinetics Shows Hint of Effect With Drug for Lou Gehrig’s Disease
There has never been much innovation to brag about in the treatment of the neurodegenerative disease that killed Yankees legend Lou Gehrig. But South San Francisco-based Cytokinetics (NASDAQ: CYTK) is reporting today on clinical trial results that offer a hint it could be onto something for treating amyotrophic lateral sclerosis (ALS).
An experimental drug from Cytokinetics met its main goal of demonstrating safety in 49 patients, while showing signs after two weeks of beating a placebo on a standard test of disease progression, according to results presented today at the American Academy of Neurology meeting in New Orleans. The result was from a small study which wasn’t designed to show a clinical benefit, and the findings were not statistically significant, meaning it could have been a fluke. But the finding is provocative enough that Cytokinetics has been emboldened to take the next step, and invest significant time and money to advance to the final phase of clinical trials normally required for FDA approval of a new drug.
“The idea you can see a change after two weeks on a functional rating scale is encouraging,” says Jeremy Shefner, the chair of the Department of Neurology at the Upstate Medical University at the State University of New York, and the study’s principal investigator. “It’s something we’ve never seen in ALS before.”
Cytokinetics has been on a long and hard journey since its founding in 1997, attempting to show there is a clinical benefit to its scientific understanding of muscle cell contraction. There are lots of potential applications of drugs that can improve muscle function, but Cytokinetics has good reason to focus its energy on ALS. This neurodegenerative disease, which robs people of their ability to walk and speak, eventually kills people when motor neurons break down so much that people can’t breathe. The only approved drug for this condition, Sanofi’s riluzole (Rilutek), only delays the time it takes for people to end up on a ventilator. About 30,000 people in the U.S. are thought to have the disease, and life expectancy is about two to five years, according to the ALS Association.
The study which Cytokinetics sponsored was designed to test the safety of its twice-daily oral pill, CK-357. The basic hope is that the Cytokinetics drug will activate a complex in muscle cells that makes them more sensitive to calcium, which should help the skeletal muscle function with more force and stamina. While the drug doesn’t attempt to solve the underlying cause of disease—the death of motor neurons—it is believed that it could help patients by improving the way their functioning muscles work, Shefner says.
Cytokinetics presented some preliminary results last November from 24 patients who got its drug in a mid-stage clinical trial. In the first part of the study, patients were randomly assigned to get either a placebo or a low, medium, or high dose of the Cytokinetics compound for two weeks. The second stage of the study was the same, except patients got a placebo or the combination of the Cytokinetics drug and the standard treatment from Sanofi.
Dizziness was the most common adverse event reported in patients, and it was mostly mild and went away shortly after treatment started, researchers said. No patients dropped out of the study early because of adverse events.
What’s more interesting, and what provides the basis for further testing, is what researchers saw on measurements of effectiveness. The main measurement of disease progression in ALS patients is something called the ALS Functional Rating Scale (ALSFRS-R), Shefner says. It’s a composite score researchers compile based on a questionnaire to patients, in which they are asked about their ability to do basic daily activities like walking, climbing stairs, speaking, swallowing, getting dressed, and brushing teeth. Patients with ALS are generally expected to decline each month, losing about 0.9 points on the ALSFRS score, says Cytokinetics CEO Robert Blum.
In this trial, researchers assessed ALSFRS scores at two points—Days 8 and 15. When data from those snapshots were combined, researchers saw an average decline of 0.5 points in the placebo group—about what would normally be expected. Those on the low dose of the Cytokinetics drug didn’t do much better, seeing an average decline of 0.3 points on their ALSFRS scores. But those on the medium and high doses did better, seeing a 0.4 point gain and a 0.6 point gain on the medium and high doses, respectively, after 15 days, researchers said. There was a 90 percent chance that the finding was due to the drug, not a result of random chance, scientists said. While that is fairly close to being a statistically valid finding, it’s not enough, because the FDA standard for statistical significance is that clinical trials need to be 95 percent certain that a drug is causing the desired effect.
Still, in a disease like ALS where there has been so little progress, this is encouraging news, Shefner says. Cytokinetics is now working on crafting a plan for a more rigorous, Phase III clinical trial that will be designed to show whether its drug is truly effective or not. The company is in conversations with regulators in the U.S. and Europe about what such a study will look like, so details aren’t yet available, but Blum says it will enroll “hundreds, not thousands” of patients, who will be dosed for a minimum of three to six months. The main goal will likely be to see how the drug affects ASLFRS scores, which Shefner said is the goal that’s most accepted within the field. A study could be designed to gather supplementary data on how well patients breathe, how strong they remain, and whether they can stay off ventilators for a longer period of time. Cytokinetics’ goal will be to start the final phase trial program before the end of 2012, Blum says.
“What we’ve seen has been consistent from preclinical tests, to tests in healthy subjects, and in ALS patients,” Blum says. “This drug is ruthlessly consistent.”
Cytokinetics isn’t the only company working hard on new treatments for ALS. Weston, MA-based Biogen Idec (NASDAQ: BIIB) is already in the third and final phase of clinical trials with a drug called dexpramipexole that is designed to work through a different biological pathway. That product is being evaluated based on a composite goal that combines the ALSFRS scores and survival times. Shefner, who has collaborated with Biogen on testing that drug as well as the one from Cytokinetics, said he’s optimistic about that program because it has already shown encouraging preliminary results after evaluating patients for three months. Ultimately, he said he’s hopeful that both will work and that they might eventually be used in combination.
That’s still an idea that’s a ways off. But Shefner kept coming back to the idea of how “unique” it is to see ALS patients improving after two weeks on therapy. He’s clearly itching to find out if that effect can be sustained over a period of several months, on an FDA-validated score. “It’s quite tantalizing,” Shefner says.