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ACHM CNGB3 PHASE 1/2 study

  • For individuals with achromatopsia caused by a mutation in the CNGB3 gene. (Each person’s mutation will be confirmed before starting the study.)
  • Goals of the study are to look at the safety and effectiveness of an experimental gene therapy to treat achromatopsia.

ACHM CNGA3 PHASE 1/2 study

  • Based on Phase 1/2 data, no further development planned.

  • Current patients will continue to be followed for safety and further evaluation.


Achromatopsia (ACHM) is an inherited condition caused by mutations in one of several genes, with the two most common being mutations in either the CNGB3 or CNGA3 genes.  ACHM is associated with extremely poor visual acuity (most affected individuals are legally blind), extreme light sensitivity resulting in daytime blindness, and complete loss of color discrimination. There is no specific treatment for ACHM, although deep red tinted glasses or contact lenses can reduce symptoms of light sensitivity and daytime blindness. AGTC is currently developing two separate AAV gene therapy product candidates for the two most prevalent forms of ACHM,  caused by either a genetic mutation in the CNGB3 or CNGA3 genes. Together, these two genetic mutations account for up to 75% of the ACHM patient population. Based on evidence from preclinical data, AGTC conducted two separate Phase 1/2 clinical trials to evaluate the safety and efficacy of AAV gene.

AGTC conducted two separate Phase 1/2 clinical trials to evaluate the safety and efficacy of AAV gene therapy product candidates in adults and children with ACHM caused by CNGB3 or CNGA3 mutations. Enrollment  is completed.  If you are a parent, caregiver or healthcare professional  and are interested in more information about the CNGB3 trial please go to to through the link below

ACHMB3 Achromatopsia Phase 1/2 Clinical Trial ( Identifier: NCT02599922)

In animal models of ACHM, untreated animals have the same signs of abnormal visual function as humans with ACHM, which is most dramatically manifested by daytime blindness under bright light conditions. Treatment of ACHM animal models with an AAV vector expressing the CNGB3 or CNGA3 protein resulted in long-term improvement in visual function. In the video below , a dog affected by ACHM (caused by a CNGB3 mutation) is unable to navigate a maze. However, four months after being treated with a gene therapy product developed by AGTC, the dog is able to successfully navigate the maze.  In the second video below , a sheep affected by ACHM (caused by a CNGA3 mutation) is first unable to navigate an obstacle course and is later shown navigating the same obstacle course successfully, three months after treatment with a gene therapy developed by AGTC.

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