A dark horse entrant into the spinal muscular atrophy field doubles its value on some PhII data
The last four years have seen a sudden explosion in treatments for spinal muscular atrophy, a neurodegenerative condition that once led patients — often young ones — with a grim prognosis and no options. The prognosis still isn’t rosy, but now there are three FDA-approved options, enough to make the choice of one difficult.
Now a fourth potential option has entered the mix. Today, Scholar Rock announced the results from a proof-of-concept testing their SMA drug by itself and in combination with Ionis’ Spinraza, showing that all patient cohorts improved on standard scales used for measuring motor function in people with SMA.
Analysts, who had been more focused on the company’s cancer pipeline, greeted the results with cautious enthusiasm. The company’s market value doubled within hours. The Cambridge biotech $SRRK is now worth around $850 million.
“We view the data as highly encouraging and providing particularly robust proof of concept within Type 2 early therapy initiators,” Cowen’s Marc Frahm said in a note to investors. “As a result, we believe SRK-015 has a clear line of site to a $1B revenue opportunity.”
Jefferies’s Michael Yee noted that it’s difficult to interpret some of the open-label data, but said the results were encouraging in a group of patients who would normally either be stable or declining. SRK-015 also works differently than existing SMA drugs, opening multiple paths to help patients and commercialize, Wedbush’s David Nierengarten added.
“Given the unique MOA of SRK-015 in the SMA space, we anticipate the commercial outlook of SRK-015 could be both as a combination agent to supplement existing therapies (e.g. nusinersen, Zolgensma) and potentially as a monotherapy as well,” Nierengarten said in a note to investors.
Scholar Rock tested their treatment, an antibody designed to inhibit the muscle growth receptor myostatin, in 39 patients with type 2 or type 3 SMA.
In the first group, 23 patients between the ages of 7 and 21 with type 3 SMA, a relatively mild form of the disease, were given SRK-015 open-label for 6 months. The 11 patients who were not taking Spinraza saw a 0.7 point bump in their motor score, while those who weren’t taking it saw an 0.3 point bump. Overall, 12 out of 23 patients saw improvements of at least 1 point and 6 out of 23 saw improvements of at least 3 points. One patient each on monotherapy and combination therapy saw a 5-point increase.
In the second open-label group, 15 patients who had type 2 SMA or had type 3 and couldn’t walk received SRK-015 on top of Spinraza. One missed the doses for Covid-19 related reasons. The rest, on average, improved by 1.4 points on a motor scale, with 10 patients improving by at least 1 point, 1 by at least 3 points and 2 by at least 6 points.
In the third group, twenty patients under the age of 5 with type 2 SMA were randomized to receive either high dose or low dose of SRK-015 along with Spinraza. The difference between the two groups was substantial, with those who received the high dose improving by more than twice as much as the low dose: 5.6 points compared with 2.4 points. All 9 evaluable high dose patients improved by at least 1 point, with 6 improving by 3 and 5 improving by 6.
Scholar Rock noted that the improvements had not yet plateaued when they reached the 6-month mark for either cohorts 2 and 3. So analysts are eager to see the 12-month data, both to track whether the improvements can continue and whether any possible placebo effect wanes.
It’ll now be one of two main points of focus going forward, with investors also keeping a keen eye on an immuno-oncology program now in Phase I. Yung Chyung, Scholar Rock’s CMO, said they’ll soon talk to regulators about a pivotal SMA trial.