Biogen has treated the first patient in a phase 4 study evaluating its spinal muscular atrophy (SMA) treatment Spinraza in infants and children who have ‘unmet clinical needs’ after previously receiving Novartis’ gene therapy Zolgensma.
The RESPOND study aims to evaluate if Spinraza can benefit SMA patients who have experienced a ‘suboptimal’ response to Zolgensma (onasemnogene abeparvovec). It will be conducted at around 20 sites globally, with researchers aiming to enrol up to 60 children with SMA.
The primary study group will include 40 infants – aged nine months or younger at the time of their first Spinraza dose – who have two copies of SMN2, meaning they are likely to develop SMA type 1, and who were six months old or younger when they received Zolgensma.
The second study group will include 20 children within a wider age range – up to three years old at the time of their first Spinraza dose.
All participants will receive the approved 12mg dose of Spinraza – which includes four loading doses and maintenance doses every four months – and will be followed up for two years.
“In clinical practice, there is a sense of urgency to address motor neuron loss in SMA from the earliest sign or even prior to symptoms, to prevent additional disease progression,” said Julie Parsons, primary investigator of the RESPOND study.
“In some patients treated with gene therapy, we have recognised that further motor neuron protection may be needed. Our hope is that results from RESPOND will demonstrate if Spinraza can optimise treatment for some of our youngest patients,” she added.
Novartis’ gene therapy was approved to treat SMA in patients aged two years and younger by the FDA in May 2019, with a price-tag of $2.1m per patient – making it the first US drug to cost over one million dollars.
Despite launching as a one-time treatment for SMA, 40% of children in the long-term study of Zolgensma have subsequently received Spinraza treatment to date, Biogen said in a statement.
Spinraza was initially launched in December 2016, with a list price of $750,000 for the initial year and $375,000 per year thereafter.
Another competitor in the SMA market – Roche’s Evrysdi (risdiplam) – was recently approved in the US for the treatment of SMA in adults and children aged two months and older, following positive results across two clinical trials of different ages and levels of disease severity, including SMA type 1, 2 and 3.
Roche has priced Evrysdi by patient weight, with a maximum cost of $340,000 per year. With benefit in younger, type 1 patients as well as in older patients with SMA, Roche’s drug is primed to take on both Spinraza and Zolgensma, with the added benefit that it can be taken at home.