$3.7M Grant Will Fund Malignant Infantile Osteopetrosis Research 


In mid-November, 2020, Rocket Pharmaceuticals announced that the company received a $3.7M grant from the California Institute for Regenerative Medicine to study potential treatments for malignant infantile osteopetrosis. In particular, the CLIN2 grant will fund research into RP-L401, a gene therapy candidate using lentivirus vectors. The grant will allow Rocket Pharmaceuticals to continue their mission of crafting gene therapy solutions for rare pediatric illnesses.


Developed by Rocket Pharmaceuticals, RP-L401 is a lentiviral vector gene therapy solution. According to an open-access chapter in Intechopen, lentiviral vectors:

are efficient vehicles for gene transfer in mammalian cells due to their capacity to stably express a gene of interest in non-dividing and dividing cells. Their use has exponentially grown in the last years both in research and in gene therapy protocols, reaching 12% of the viral vector based clinical trials in 2011.

Earlier this year, the FDA accepted the Investigational New Drug Application (IND) for RP-L401, and additionally awarded it Fast Track designation. The burgeoning research and development is spurred thanks to the CIRM grant. Previously, Rocket Pharmaceuticals received another CIRM grant for their gene therapy option for patients with Leukocyte Adhesion Deficiency-I.  In this case, the grant will assist with clinical trial costs, manufacturing, and providing RP-L401 to enrolled patients. Two patients will enroll in the initial Phase 1 trial. Ultimately, the trial will determine the safety, efficacy, and tolerability of RP-L401.

Malignant Infantile Osteopetrosis

Overall, malignant infantile osteopetrosis is inherited in an autosomal recessive pattern; children must inherit one defective gene from each parent for the condition to occur. Typically, the gene mutation is found on the long arm of chromosome 11 (11q12-q13). As a result, patients develop this rare skeletal disorder. Normally, our osteoblast cells prompt healthy bone formation. But in malignant infantile osteopetrosis, there are not enough osteoblasts, causing dense and easily fractured bones. An estimated 8-40 American infants are born with this condition each year. Symptoms include:

  • Failure to thrive
  • Delayed growth
  • Frequent infections
  • Anemia
  • Facial paralysis
  • Blindness and/or deafness
  • Neurological delays
  • Bone fractures

Typically, malignant infantile osteopetrosis is fatal within the first 10 years. Currently, there is only one treatment option: an allogenic bone marrow transplant with hematopoietic stem cells (HSCT). However, survival rates are still relatively low, suggesting a need for new therapeutic options.

Learn more about malignant infantile osteopetrosis here.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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