AB Science SA announced via press release this week information from their recently completed phase 3 clinical trial of Masitinib in people with ALS. Most importantly, AB Science reported that the clinical trial met the pre-specified primary endpoint – change in ALSFRS-R score from baseline to week 48. ALSFRS-R is a clinical scale used to determine the progression of a person with ALS overtime.

The trial enrolled nearly 400 people with ALS, and split them up in three different groups: high dose of, low dose and placebo. All three arms included the use of Riluzole together with Masitinib or placebo. Participants were enrolled primarily in two centers in Spain between 2012 and 2015. Investigators collected final data toward the end of 2016. The information provided this week were "top-line" results, with additional data expected later this year. This study was larger and longer than some other Phase 2b clinical trials that have occurred in the past in ALS.

Not all pre-specified endpoints have been reported on yet, nor is all the relevant data from this sizable clinical trial yet published. This is not uncommon. Clinical trial sponsors often release complete results at relevant scientific or clinical conferences and through peer reviewed journals. According to AB Science, additional safety and efficacy data is to be presented at the upcoming ENCALS meeting in May 2017 being held in Slovenia. The table below summarizes outcome measure data provided by AB Science through press releasesclinical trial design published on clinicaltrials.gov and a non-confidential slide deck published on their website:


Reported Impact of Masitinib Phase 2/3 Trial on Outcome Measures


Outcome Measures

Low Dose

(3 mg/kg/day)

High Dose

(4.5 mg/kg/day)

ALS Functional Rating Scale Revised


No statistically significant impact

Statistically significant impact

Forced Vital Capacity (FVC)

Not reported

Not reported

Combined Assessment of Function and Survival (CAFS)

Not reported

Not reported

Quality of Life (ALSAQ-40)

Statistically significant impact

Statistically significant impact

Progression Free Survival (PFS)

No statistically significant impact

Statistically significant impact


Previously, ALS TDI reported on the interim report from AB Science, and this highly anticipated read out was mentioned as part of our recent webinar Top 10 Things to Watch for in ALS Research in 2017. Since the interim report, AB Science has published and presented additional preclinical studies of their drug’s impact in ALS models. This sharing of information and data is vitally important to people with ALS, neurologists, allied health professionals, scientists and, of course, regulators.

What’s the next step for Masitinib?

At this time, Masitinib is not approved to be marketed as a treatment for ALS by the European Medicines Agency (EMA) nor the Food and Drug Administration (FDA).

AB Science filed for marketing authorization in ALS at the EMA in September 2016. It is expected that AB Science will share this data with EMA. The EMA is expected to work toward a decision on marketing authorization for Masitinib as a treatment for ALS by the end of 2017. 

In the United States, AB Science says that they will discuss the trial results and potential next steps with officials at the FDA.

AB Science also stated that they plan to execute a “confirmatory phase 3 study" by the end of 2017 as well.  No further information about the enrollment sites or criteria for that study are available at this time. ALS TDI will post the trial in its Clinical Trial Database as soon as more details become available.

Bottom Line

While Masitinib is not yet approved by the FDA or EMA to be marketed as a treatment for ALS, the results announced this week are encouraging. We look forward to AB Science and the investigators sharing more information from this study and the presentation of data at upcoming scientific conferences such as ENCALS, AAN and the International Symposium on ALS/MND Research, as well as the eventual publication of the results in peer reviewed journals.

The ALS Therapy Development Institute would like to recognize the nearly 400 people with ALS and their families who participated in the phase 2/3 study of Masitinib over the last 5 years. Each of those individuals invested a significant amount of their time into this study, which we consider encouraging. There are several clinical trials occurring worldwide in ALS, including several studies on potential treatments. Volunteers are needed still for many of them including those listed here

CORRECTION: An earlier version of this article said the ENCALS meeting would occur in Slovakia, rather than Slovenia.