The U.S. FDA granted Fast Track designation to RP-L401, a lentiviral vector (LVV)-based gene therapy for the treatment of Infantile Malignant Osteopetrosis (IMO) on 28,August,2020, as announced by a leading clinical-stage company progressing an integrated and sustainable pipeline of genetic treatments for rare childhood illnesses.

Infantile Malignant Osteopetrosis is an uncommon, acute monogenic bone resorption illness. It is marked by neurologic anomalies, skeletal malformations and bone marrow failure. Consequently, fatality is common within the first 10 years of life. It is described by deformity of 1 or more limbs, with pain and limitation of movement of the affected limb. As estimated, 1 in 200,000 suffers from this condition.

To determine the overall efficacy of RP-L401, the company’s Phase 1 clinical trial of RP-L401 for the treatment of IMO will register 2 patients (aged 1 month or older). The primary efficacy, comprising of prospective improvements in hematologic status, bone irregularities/density, and endocrine anomalies will also be examined in this trial.