SiSaf gets green light from FDA for osteopetrosis treatment

By Isabel Cameron

- Last updated on GMT

© Getty Images
© Getty Images

Related tags Fda Food and drug administration FDA approval Clinical trial orphan disease

SiSaf has been granted Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation (PRDD) by the US Food and Drug Administration (FDA) for its osteopetrosis treatment, SIS-101-ADO.

ODD from the FDA provides SiSaf with incentives such as tax credits for clinical trials, exemption from user fees, and expanded marketplace exclusivity.

In addition, PRDD entitles SiSaf to apply for a priority review voucher that can be used to have the drug approval process expedited by the FDA.

Sisaf’s treatment was awarded PRDD on the basis of the serious or life-threatening manifestations of Autosomal Dominant Osteopetrosis Type 2 (ADO2) that primarily affect children, including blindness from optic nerve compression, anomalies in dental and craniofacial development, and scoliosis.

There are currently no approved treatments for Osteopetrosis ADO2 and no other treatments currently in clinical trials.

Therefore, if approved, SiSaf’s SIS-101-ADO would be the first treatment for Osteopetrosis ADO2 and could provide life-altering benefits for those who suffer from this debilitating disease.

SiSaf is currently preparing for first-in-human clinical trials.


SIS-101-ADO combines an siRNA that suppresses the expression of CLCN7 with SiSaf’s Bio-Courier delivery technology.

By downregulating the expression of CLCN7, a mutant gene expressed by osteoclasts and other cell types responsible for causing ADO2, the RNA therapy restores bone mass and quality to nearly normal levels. 

Genetic skeletal disorders such as ADO2 account for 5% of all birth defects globally, yet many unmet needs and challenges remain for providing safe and effective treatments.

According to SiSaf, its proprietary Bio-Courier technology has the potential to accelerate the development of new RNA-based treatments. The technology addresses the limitations of other RNA delivery technologies by stabilizing lipid nanoparticles with bioabsorbable silicon.

“Being granted Orphan Drug Designation and Rare Pediatric Disease Designation is a major milestone in our drive to move our revolutionary siRNA treatment forward to alleviate the pain and suffering that Osteopetrosis ADO2 inflicts,” said Dr. Suzanne Saffie-Siebert, founder and CEO of SiSaf.

“SIS-101-ADO ushers in the potential for a new era of personalized care and treatment options for ADO2 and other rare bone and skeletal diseases.

“There has been an explosion of interest in RNA therapeutics for a wide range of medical conditions and SiSaf’s innovative Bio-Courier delivered siRNA technology holds the promise to address some of the most intractable diseases.”

SIS-101-ADO and other Bio-Courier formulated drugs will not only be able to treat rare skeletal disorders but can clear the way for therapeutics for other rare diseases once thought impossible to treat, Saffie-Siebert added.

Related topics Bio Developments Emerging Markets

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