Recently, the news that "one injection sold 700,000" has been searched on Weibo. This 700,000-injection medicine is called Nosinasina Injection, which is used to treat spinal muscular atrophy (SMA).
In December 2016, Nosinassen Sodium Injection was approved for the first time in the United States. It is the world's first precision targeted therapy for SMA. It was subsequently approved for the treatment of SMA in the European Union, Brazil, Japan, South Korea, Canada and other countries. In April 2019, Noxinassen Sodium Injection was launched in my country for the treatment of 5qSMA, that is, SMA caused by the SMN1 gene mutation on chromosome 5. It became the first drug in China that can treat SMA. The price of the drug has remained high, with a price of US$125,000 (approximately RMB 870,000) in the United States.
This hot search made more people pay attention to this disease. So, what exactly is spinal muscular atrophy? In addition to this drug, are there other drugs that can be treated?
About spinal muscular atrophy
Everyone should have heard of muscular dystrophy, but may not know much about spinal muscular atrophy. Spinal muscular atrophy is a type of disease that causes progressive muscle weakness and muscle atrophy due to the degeneration of the motor cells in the anterior horn of the spinal cord. It is a hereditary neuromuscular disease and is also known as the "killer of genetic diseases in infants and young children." Clinical manifestations include slow movement, decreased muscle tone, and proximal muscle atrophy. The patient eventually died of respiratory failure and severe lung infection, which is a fatal disease.
According to the time of onset and the course of the disease, spinal muscular atrophy can be divided into infant, juvenile and intermediate types [1]. Among them, infantile spinal muscular atrophy usually develops within 6 months after birth. About 30% of the children develop the disease in the neonatal period. The course of the disease progresses quickly and the mortality rate is high. Most of the children die within 2 years of age. Adult spinal muscular atrophy occurs more than 20-30 years old, and the incidence is about 0.32/10 000.
There is no effective therapeutic drug, stem cells provide new ideas
At present, there are few clinical, pathological and genetic studies on spinal muscular atrophy, and there is no effective treatment drug. In addition to the 700,000-a-dose drugs mentioned above, scientists have also developed some neuroprotective agents, such as riluzole, orisosi, for the treatment of spinal muscular atrophy.
At the same time, with the emergence of regenerative medicine, stem cell transplantation provides a new idea. Stem cell transplantation can replace damaged nerve cells and promote the reconstruction of cell structure and function. It is a new idea and new method for treating neurological diseases.
For spinal muscular atrophy, in 2012, Italian scientists used stem cell transplantation to successfully control the progress of spinal muscular atrophy in a mouse model, and published the results in Science Translational Medicine (Science Translational Medicine). Translational Medicine) magazine[2], this result provides a strong proof for the clinical application of stem cell transplantation to treat spinal muscular atrophy.
The article stated that the transplanted neurons integrated into the spinal cord can reduce motor dysfunction and form a neuromuscular junction with the muscle tissue near the spinal cord. Transplanting neurons also promoted the survival of endogenous neurons carrying a spinal muscular atrophy mutation, indicating that this treatment also provides neuroprotection for surrounding tissues.
Initial results of human clinical trials are gratifying
In recent years, there have been registrations of clinical trials of stem cell treatment of spinal muscular atrophy at home and abroad.
From the clinical trial project on the treatment of spinal muscular atrophy with stem cells registered on the clinicaltrials.gov website, researchers at Tehran Medical University in the Islamic Republic of Iran, in order to explore the therapeutic effect of mesenchymal stem cells on infantile spinal muscular atrophy, Twenty volunteers were included for interventional therapy. A group of 10 patients received an EMG examination every 3 months without any intervention of cell therapy. Another group of 10 patients will receive transplantation of allogeneic mesenchymal stem cells every 3 weeks. The electrical activity of the muscles is measured by an electromyogram to evaluate the effect before and after treatment.
In our country, according to the published literature [3], researchers used stem cell transplantation for a patient with spinal muscular atrophy admitted to the treatment, and injected 50 mL of stem cell nutritional factor intravenously, once a week, 4 times for a course of treatment. The results of the study showed that the child stood stable after 3 months and walked more stable than before. At the same time, targeted nursing care was implemented for the patients' nursing problems during the treatment process, and satisfactory results were achieved.
Let’s look at another research report on the treatment of spinal muscular atrophy in children with mesenchymal stem cell transplantation[4]. This study included a child who had been diagnosed with spinal muscular atrophy, but was ineffective after medication and rehabilitation. Carry out mesenchymal stem cell transplantation treatment. The transplantation route is the first intravenous infusion, and the next 3 subarachnoid injections, 1 time/week, each time the number of cells reaches (4-6)×10^7, 4 times as a course of treatment. Nervous system physical examination, laboratory examination, muscle enzymes, FIM score, electromyography, etc. should be perfected before treatment and half a year after treatment. The results showed that compared with before transplantation, the patient's muscle enzyme levels decreased, and the FIM score increased from 68 to 93. The muscle strength of the lower limbs of the child 6 months after the transplantation was increased, and the self-care ability was improved. During the 10-month follow-up, the child did not have any adverse reactions.
This clinical research case allows people to see the prospects of stem cell transplantation in the treatment of spinal muscular atrophy.
There is still much room for exploration on the treatment of spinal muscular atrophy. Stem cell transplantation brings new hope for the treatment of spinal muscular atrophy. It is believed that in the near future, the treatment of spinal muscular atrophy will make greater breakthroughs, so that the disease can be treated widely and effectively, benefiting more families and reducing the burden on society.
