On June 26th, the clinical research results of GC301, an AAV gene therapy drug independently developed by Beijing Genecradle Therapeutics Technology Co., Ltd. for the treatment of Infantile-Onset Pompe Disease (IOPD), were officially published in the form of an original article in the international top-tier medical journal The New England Journal of Medicine (NEJM). As the world's oldest and most influential comprehensive medical journal, NEJM is renowned for its rigorous peer-review mechanism and strong clinical translation value orientation, long leading the direction of medical research development. The research results published in it are often used by the World Health Organization (WHO) and food and drug administration agencies of various countries as important evidence-based medical references.

This study is not only the first disclosure of the First-in-Human (FIH) clinical trial results of GC301, the world's first gene therapy drug for infantile Pompe disease, but also marks the full-chain breakthrough of China's original First-in-Class gene therapy from concept validation to clinical benefit validation. The publication of this paper provides important references and perspectives for the international medical and industrial communities to better understand this advanced therapy and brings new hope of "one-time treatment, long-term efficacy" to global Pompe disease patients.

Research Highlights

Full-Spectrum Breakthrough from Source Innovation to Clinical Validation 

Gene Cradle

1. Infantile-Onset Pompe Disease (IOPD) is widely recognized as a complex and challenging disease to treat.

Infantile Pompe disease is caused by mutations in the gene for acid alpha-glucosidase (GAA), and the lack of this enzyme leads to the abnormal accumulation of glycogen within cells, particularly in vital organs such as muscles, heart, and respiratory system. The accumulation of glycogen causes severe impairment of cellular function, thereby triggering a wide range of clinical symptoms. The underlying pathological mechanism is a complex multi-level biological process involving gene mutations, enzyme deficiency, and metabolic abnormalities, making the intervention points in the treatment process extremely numerous.

A key issue in gene therapy is how to effectively deliver the normal GAA gene into the patient's cells, especially targeting muscle and heart tissue.

2. Innovative design of GC301 gene therapy: A systemic single-dose strategy based on AAV9 vector and codon optimization.

The drug design of GC301 is based on the recombinant adeno-associated virus serotype 9 (rAAV9) vector, carrying the human acid alpha-glucosidase (GAA) gene optimized by codon. AAV9, with its high efficiency in penetrating the blood-brain barrier and targeting the heart and skeletal muscle, has become an ideal vector for treating Pompe disease with multi-system involvement. Genecradle Therapeutics further innovatively used tissue-specific promoters to achieve widespread expression of the GAA gene in systemic tissues (Fig. S1). It broke through the limitations of traditional enzyme replacement therapy (ERT) that cannot reach the central nervous system. Preclinical studies have shown that GC301 can significantly reduce glycogen deposition in the heart, muscles, and brain in mouse and non-human primate models, and its safety is controllable, laying a solid foundation for subsequent clinical trials.  

3. Good drug safety and significant extension of subjects' survival.

No drug-related serious adverse events (SAEs) occurred during GC301 treatment and follow-up, and adverse events possibly related to the drug were mainly transient liver enzyme elevation (AST/ALT), which required no intervention.Three subjects who entered long-term follow-up maintained survival and continued to benefit over a follow-up period of 22-29 months, far exceeding the median survival of untreated children (around 8 months).4. Significant reversal of myocardial hypertrophy and stable ejection function.After a single intravenous injection of GC301, the left ventricular mass index (LVMI) of the subjects decreased and remained stable, and the ejection fraction (LVEF) was always maintained within the normal range. In a typical case, P1's LVMI decreased from a baseline of 157.15 g/m² to 67.83 g/m² (a decrease of 57%), and the LVM Z-score decreased from 13.05 to 2.29, with myocardial hypertrophy nearly regressing (Fig. 1 C). Despite short-term fluctuations in indicators caused by respiratory tract infections, LVEF remained stable within the normal range, confirming the durable efficacy of GC301 on cardiac pathology (Fig. 1 D).

5. Milestone achievements in motor development, with neurodevelopment approaching healthy levels.

After GC301 treatment, the Hammersmith Infant Neurological Examination (HINE) scores of the children significantly improved. Two subjects had scores of 74 and 75 points at 12 months of age (the threshold for healthy infants is >72 points), and gradually achieved key abilities such as sitting alone and assisted walking (Fig. 1A). In long-term follow-up, two subjects achieved independent standing and walking at 22-29 months, surpassing the functional prognosis of patients receiving traditional enzyme replacement therapy (ERT) (Fig. 1 B).

6. Long-term increase in peripheral blood GAA enzyme activity with low immunogenicity.

After GC301 treatment, the peripheral blood GAA enzyme activity of the children significantly increased compared to the baseline and remained stable for more than 52 weeks (Fig.2A). At the same time, the vector genome rapidly and continuously decreased after administration (Fig.2B), effectively reducing the potential risks related to immunity. What is particularly crucial is that no anti-GAA antibodies were detected throughout the study (Fig. S8). This result suggests that GC301 gene therapy has the potential to overcome the bottleneck of efficacy attenuation caused by high-titer anti-GAA antibodies in existing ERT therapy.

Breaking the Traditional "One Injection Cures All" Gene Therapy Opens a New Era in Pompe Disease Treatment 

Gene Cradle

Infantile Pompe disease is a severe lysosomal storage disease that often leads to death in infancy if not treated in time. Traditional enzyme replacement therapy (ERT) can partially improve the function of patients' myocardium and skeletal muscles, but it requires lifelong repeated dosing and has no significant effect on central nervous system lesions. The innovative AAV gene therapy product GC301 achieves long-term expression of endogenous acid alpha-glucosidase (GAA) in patients through a single dose, showing the potential to reverse myocardial and skeletal muscle damage in animal and preliminary clinical studies. More importantly, it may penetrate the blood-brain barrier, providing new hope for delaying and even improving neurological damage, and laying the foundation for "functional cure" of Pompe disease. The publication of this clinical research result systematically validates the feasibility and wide applicability of AAV-mediated gene therapy in systemic rare diseases and provides key references for the development of treatment strategies for other monogenic hereditary diseases.

专家观点Expert Opinions 

Gene Cradle

This study was co-corresponding authored by Professor Feng Zhichun from the Seventh Medical Center of the General Hospital of the People's Liberation Army, Dr. Wu Xiaobing from Beijing Genecradle Therapeutics Technology Co., Ltd., and Professor Xiong Hui from Beijing Children's Hospital Affiliated to Capital Medical University. The co-first authors include Deputy Chief Physician Ma Xiuwei, Dr. Zhuang Lu from the Seventh Medical Center of the General Hospital of the People's Liberation Army, Ma Wenhao from Beijing Genecradle Therapeutics Technology Co., Ltd., and Dr. Li Jun from the Seventh Medical Center of the General Hospital of the People's Liberation Army.

The New England Journal of Medicine published a dedicated commentary by international authorities on Pompe disease research, Professors G. Parenti and N. Brunetti-Pierri from the University of Naples, Italy, highlighting that "this study represents an important milestone in the treatment of this complex and lethal disease."

Dr. Wu Xiaobing, co-corresponding author and founder of Genecradle Therapeutics, stated:

The clinical breakthrough of GC301 is the result of a decade of dedicated effort by our team. From vector optimization, promoter design to the entire production process, we have innovated across the board, ultimately achieving a balance between the efficacy and safety of AAV gene therapy for Pompe disease. The publication of this paper, along with the FDA's orphan drug designation received this year, are both international recognitions of the clinical value of GC301. We will accelerate the drug's market launch and actively engage in international cooperation, with the hope that this therapy can benefit global Pompe disease patients as soon as possible.

The emergence of a new drug and its benefits to the public are inseparable from the support and participation of the people. We sincerely thank all the volunteers and their families who participated in the clinical trials. It is their trust and support that enable us to continuously advance drug development and clinical application, bringing hope to patients. We earnestly hope that more attention can be paid to the research and development and clinical application of innovative drugs, to witness together the breakthroughs and progress of gene therapy in China. In the future, Genecradle Therapeutics will continue to delve into the field of gene therapy, offering more 'Made in China' solutions to address unmet clinical needs.