A 'Too Adventurous' Trial: The Death of a 6-Year-Old Girl

The first case Nikolich commented on involved a 6-year-old girl who died at Xinhua Hospital in Shanghai in March 2025 . She received an experimental gene-editing treatment for a rare genetic brain disorder — Snijders Blok-Campeau syndrome — in which viral particles were injected into her spine to deliver a base editor designed to rewrite a mutated gene . She died within days from a severe immune reaction .

Nikolich called the trial "too adventurous" given the immaturity of the science . Independent experts who reviewed the case later expressed concern that safety signals in animal studies may have been overlooked and that the trial should not have proceeded . The girl's parents paid more than $860,000 to fund the preclinical work, a financial arrangement not disclosed in the Nature paper detailing the animal studies .

The death was never publicly reported until Science and Retraction Watch jointly published an investigation on July 23, 2026 . Shanghai Jiao Tong University School of Medicine subsequently launched a comprehensive investigation .

A Second Death: Duchenne Muscular Dystrophy Trial

The second case involved a boy with Duchenne muscular dystrophy who died in Shanghai in August 2025 after receiving a high dose of HuidaGene Therapeutics' CRISPR gene-editing therapy in a first-in-human trial . The company attributed the death to acute respiratory distress syndrome as part of a severe immune reaction to the therapy . Clinical trial records show the study only enrolled boys aged 4 to 8 .

The Core Scientific Concern: Systemic Effects Are Still Unknown

Nikolich raised a fundamental biological challenge that underpins both tragedies: scientists still "don't know precisely how changing a gene will affect the whole body" . While techniques are reasonably well established in animal experiments, Nikolich said they "really haven't been as mature for human studies" .

This gap in understanding is particularly acute for nervous system therapies, where the effects of editing genes in the brain or spinal cord can ripple through complex neurological networks in unpredictable ways. The severe immune reactions seen in both Shanghai cases highlight a critical safety risk: the body's immune system can mount a fatal response to the viral vectors used to deliver editing machinery, even when preclinical data appears manageable .

Global Regulatory Implications

The undisclosed deaths have reopened debate about how regulators should oversee investigator-initiated trials, a pathway that has allowed accelerated human testing in China with less oversight than standard clinical trials . Similar accelerated trial models are now being debated in the United States and Europe . Experts stress that prompt disclosure and honest investigation of fatalities are paramount to maintaining public trust in gene-editing therapies .

Nikolich's assessment suggests a broad consensus is forming: the promise of CRISPR and base-editing technologies is real, but the rush to human testing has outpaced the science. Until researchers can predict and control how a genetic edit will affect the entire organism — not just the target tissue — human trials remain a high-risk endeavor.

For families facing devastating genetic conditions, the wait is painful. But Nikolich's message is clear: patience is not just prudent — it is necessary to avoid repeating tragedies that could undermine the entire field.

A 'Too Adventurous' Trial: The Death of a 6-Year-Old Girl

The first case Nikolich commented on involved a 6-year-old girl who died at Xinhua Hospital in Shanghai in March 2025 . She received an experimental gene-editing treatment for a rare genetic brain disorder — Snijders Blok-Campeau syndrome — in which viral particles were injected into her spine to deliver a base editor designed to rewrite a mutated gene . She died within days from a severe immune reaction .

Nikolich called the trial "too adventurous" given the immaturity of the science . Independent experts who reviewed the case later expressed concern that safety signals in animal studies may have been overlooked and that the trial should not have proceeded . The girl's parents paid more than $860,000 to fund the preclinical work, a financial arrangement not disclosed in the Nature paper detailing the animal studies .

The death was never publicly reported until Science and Retraction Watch jointly published an investigation on July 23, 2026 . Shanghai Jiao Tong University School of Medicine subsequently launched a comprehensive investigation .

A Second Death: Duchenne Muscular Dystrophy Trial

The second case involved a boy with Duchenne muscular dystrophy who died in Shanghai in August 2025 after receiving a high dose of HuidaGene Therapeutics' CRISPR gene-editing therapy in a first-in-human trial . The company attributed the death to acute respiratory distress syndrome as part of a severe immune reaction to the therapy . Clinical trial records show the study only enrolled boys aged 4 to 8 .

The Core Scientific Concern: Systemic Effects Are Still Unknown

Nikolich raised a fundamental biological challenge that underpins both tragedies: scientists still "don't know precisely how changing a gene will affect the whole body" . While techniques are reasonably well established in animal experiments, Nikolich said they "really haven't been as mature for human studies" .

This gap in understanding is particularly acute for nervous system therapies, where the effects of editing genes in the brain or spinal cord can ripple through complex neurological networks in unpredictable ways. The severe immune reactions seen in both Shanghai cases highlight a critical safety risk: the body's immune system can mount a fatal response to the viral vectors used to deliver editing machinery, even when preclinical data appears manageable .

Global Regulatory Implications

The undisclosed deaths have reopened debate about how regulators should oversee investigator-initiated trials, a pathway that has allowed accelerated human testing in China with less oversight than standard clinical trials . Similar accelerated trial models are now being debated in the United States and Europe . Experts stress that prompt disclosure and honest investigation of fatalities are paramount to maintaining public trust in gene-editing therapies .

Nikolich's assessment suggests a broad consensus is forming: the promise of CRISPR and base-editing technologies is real, but the rush to human testing has outpaced the science. Until researchers can predict and control how a genetic edit will affect the entire organism — not just the target tissue — human trials remain a high-risk endeavor.

For families facing devastating genetic conditions, the wait is painful. But Nikolich's message is clear: patience is not just prudent — it is necessary to avoid repeating tragedies that could undermine the entire field.