PackGene Empowers Gene Therapy, Opening a New Journey for Children with Rett Syndrome

On February 14, 2025, in the research ward at the Guangzhou Women and Children’s Medical Center (Zengcheng Branch), a Rett syndrome (RTT) patient named Xixi (pseudonym) from Shanxi brought tears of relief to her father’s eyes. In recent years, Xixi had been plagued by severe symptoms and discomfort—yet now, she has shown encouraging improvements. She can now express her needs proactively through crying and agitation. This progress comes as a positive result of an investigator-initiated clinical study jointly carried out by the team of Professor Zhou Wenhao, President of Guangzhou Women and Children’s Medical Center, and Professor Qiu Zilong from the Songjiang Research Institute of the School of Medicine at Shanghai Jiao Tong University. PackGene is honored to help support the successful translation of this IIT project from R&D to clinical application.

Gene Therapy “Fills” Hope for RTT Children

Xixi is 6 years old. Her parents recall that when she was around one year old, she was still able to say simple words such as “dad” and “mom.” In 2021, Xixi began to show clear regression: frequent hand-wringing, teeth grinding, and a gradual loss of her previously acquired walking and speaking abilities. After two years of seeking care across multiple hospitals, Xixi was ultimately diagnosed with Rett syndrome in a hospital in Beijing through genetic testing.

Rett syndrome is an ultra-rare disease with an incidence of approximately 1/10,000 to 1/15,000. It was once regarded as an “incurable illness without a cure.” Patients are predominantly female. In early stages of disease onset, individuals may experience intellectual regression, regression in language and motor skills, and stereotyped hand movements, all of which severely affect normal development and growth. Since the first RTT case was confirmed in China in 1988, patients have faced a long-standing dilemma of “no available treatment.” Traditional rehabilitation training offers limited benefits, and while drugs have been marketed abroad, they are costly and difficult for patients in China to access.

After diagnosis, Xixi’s parents spent nearly two years searching for experts and coordinating efforts to pursue a chance at life for their daughter. In 2024, they finally saw hope. On February 14, 2024, Xixi became the first child in Central China to receive RTT gene therapy. After one month of follow-up, her motor function, ability to eat, and capacity to proactively express needs have all shown clear improvements.

The gene therapy clinical study applies research outcomes accumulated over nearly 20 years by Professor Qiu Zilong’s team at the Songjiang Research Institute of the School of Medicine at Shanghai Jiao Tong University. The study uses a self-developed adeno-associated virus (AAV) vector carrying a normal MECP2 gene. The therapy is precisely delivered into the patient’s brain via a single intrathecal injection.

PackGene provided high-quality AAV vector services for this study, drawing on its expertise in gene therapy and its extensive project experience, to support the smooth advancement of the gene therapy program. In simple terms, the AAV vector can be imagined as a “fire truck” capable of rapidly reaching the scene of an emergency. The therapeutic agent enters cerebrospinal fluid through the intrathecal pathway along the spine and then “travels” to the brain, delivering the normal MECP2 gene to targeted damaged neurons. By compensating for missing or abnormal genetic function, it helps restore neural cell function and alleviates neurodevelopmental disorder symptoms in the child.

This Research-Grade Clinical Trial Will Enroll 6 Patients

“Long-term benefits can be achieved through a single administration, which could greatly reduce both the financial and treatment burden on patients’ families,” said Professor Qiu Zilong.

In prior animal studies, the MECP2 gene therapy candidate (RETT-001) demonstrated efficacy and safety superior to other similar products in both domestic and international markets. Animal survival periods were significantly extended, and motor function showed marked improvement.

This research-grade clinical trial plans to enroll six RTT children aged 4 to 10. Guangzhou Women and Children’s Medical Center has established a research ward integrating ethics review, risk monitoring, and standardized operating procedures. With close multidisciplinary collaboration among the Department of Critical Care Medicine, Pediatrics, Neurology, and other specialties, the study provides comprehensive real-time monitoring to ensure treatment safety and compliance with standards.

Professor Zhou Wenhao noted that the research team will continue to track changes in Xixi’s language, cognition, and behavior, and will conduct multiple assessments including electroencephalography (EEG) and immunological indicators. Meanwhile, the team also plans to expand the clinical trial scale to achieve a more mature and broadly accessible treatment approach as early as possible, so that more RTT children can benefit.

PackGene, a CRO & CTDMO specializing in CGT delivery for more than a decade, is honored to witness—again and again—the return of hope for life to patient families through concerted efforts from multiple parties. Moving forward, PackGene will continue to deepen its CGT delivery expertise, further enhance its technology and service quality, provide strong support for more gene therapy research, and work toward its mission of enabling “ordinary people to afford gene therapy.”