Early data win for AveXis’ SMA Type 1 therapy but Biogen's med also strong

AveXis ($AVXS) released interim data over the weekend indicating that its experimental new treatment for the devastating genetic disorder spinal muscular atrophy (SMA) Type 1 could help patients hit key motor development milestones, including helping some walk without support.

The data coming out of its small Phase I study of the FDA breakthrough-designated gene therapy AVXS-101 as of 15 Sept. showed, according to the biotech, that two-thirds of patients in cohort 2 (which is what the company is looking to dose its patients on) “had achieved the ability to sit unassisted, including one patient whose achievement of this milestone was confirmed after September 15.”

In this part of the study, AveXis said that 11 of 12 patients achieved head control, while 7 of 12 patients could roll over completely and 11 of 12 patients could sit with support.

“Two patients are now walking independently, including one whose achievement of this milestone was confirmed after September 15," the company, which saw a $95 million IPO at the start of the year, said in a statement. “These two patients each achieved earlier and important developmental milestones such as crawling, standing with support, standing alone and walking with support.”

SMA can affect up to 10,000 children around the world. The disease has four types, but AveXis is focusing on Type 1, the most severe: Around 90% of children born with this type never see their second birthday, and in their short lives will never sit, crawl or walk. Right out of the gate, these children have a poor quality of life, and the disease takes hold rapidly, with most ending up on a ventilator before dying.

SMA Type 1 occurs when a protein, known as SMN, is not produced sufficiently because the SMN1 gene is missing. Without this protein, the motor neurons die as do other key tissues, such as muscle.

“The preliminary clinical observations of extended event-free survival, sustained increases in motor function and achievement of developmental milestones in patients receiving a one-time infusion of AVXS-101 have far exceeded what has been observed with natural history,” said Dr. Suku Nagendran, SVP and CMO of AveXis, in the statement. “These preliminary results demonstrate the potential of AVXS-101 to positively impact quality of life and as such alter the course of disease in these children with SMA Type 1.”

The biotech, which last month was also awarded an honorable mention in the Fierce 15, was rumored by Jefferies analyst Biren Amin a few weeks back as having found a patient they believe is in the AVXS-101 trial “whose parents posted a video of her walking.”

Amin said at the time that "We believe her achievement to walk is significant given that she is a Type 1 SMA baby w/2 copy number and would not in any normal circumstance be expected to walk.”

Amin reiterated his buy rating and boosted the price target from $42 to $50. As of close Friday, before these data were released, AveXis’ shares were up 5.2% with a market cap of $1.3 billion, and its shares were trading at $47.51. It was up 1.45% as the markets opened Monday morning. 

“To date, the majority of patients who received the proposed therapeutic dose of AVXS-101 have achieved key milestones and two-thirds of these patients can sit independently--a fact completely inconsistent with the known disease course, as children with untreated SMA Type 1 will never sit unassisted,” said Sean Nolan, president and CEO of AveXis, in the statement. “We are encouraged by these interim data, and continue to work diligently to bring this gene therapy to the children suffering from this devastating condition.”

These latest data were published at this year’s 2016 World Muscle Society Congress in Granada, Spain, with rivals Biogen ($BIIB) and Ionis ($IONS) also publishing some new data from their investigational SMA med nusinersen.

In the Phase III Endear study, their med showed statistically and clinically significant improvement in the primary endpoint, which included greater movement in kicking, walking, crawling and sitting, than worsened.

Biogen and its partner are ahead of AveXis in the race to market and have already completed the rolling submission of an NDA to the FDA for approval of nusinersen, with an EMA submission planned in the coming months.

As well as its Endear test, geared up for infantile-onset SMA (who are most likely to develop Type 1), it also posted what it called “encouraging preliminary results from Nurture,” a Phase II open-label study in presymptomatic infants, as well as a recent analysis of the ongoing midstage open-label study in patients with later-onset SMA (consistent with Types 2 or 3).

Nusinersen works as an antisense oligonucleotide (ASO) that is designed to alter the splicing of SMN2, a gene that is nearly identical to SMN1, in order to increase production of fully functional SMN protein.

AVXS-101, meanwhile, is designed to address the monogenetic root cause of SMA and prevent further muscle degeneration by addressing the defect in and/or loss of the primary SMN gene.