BioMarin stands tall with first approved drug for rare disease that causes dwarfism

EU Flags at the European Commission Building

A genetic disorder that slows bone growth and leads to dwarfism now has an approved drug, a biologic therapy developed by BioMarin Pharmaceutical. The European Commission decision announced Friday makes the drug, vosoritide, the first drug therapy for the rare disease, whose complications are typically addressed by surgery.

The disease, achondroplasia, is caused by a mutation to the gene that produces fibroblast growth factor receptor 3 (FGFR3), a protein that down-regulates bone growth. Activity of FGFR3 is typically kept in check by a peptide called C-type natriuretic peptide (CNP). BioMarin’s drug, given as a once-daily injection, is an analog of that peptide. The San Rafael, California-based rare diseases drug developer will market the drug under the name “Voxzogo.”

Achondroplasia is usually caused by a spontaneous mutation, according to the National Organization of Rare Disorders. In about 20% of patients, the condition is inherited. The condition is the most common cause of dwarfism. People who have achondroplasia have short limbs, leading to an average height of 4 feet. Potential complications include compression of the spinal cord, sleep apnea, bowed legs, and recurrent ear infections. The main treatments are surgeries to address spinal and limb problems.

BioMarin has only tested its drug in children spanning the age range when growth plates are still open. In an open-label dose-finding Phase 2 study enrolling 35 children 5 to 14, the annual growth velocity increased from baseline for all groups measured through 42 months. Results were published in 2019 in the New England Journal of Medicine.

The company proceeded to test the drug in a placebo-controlled Phase 3 study enrolling more than 120 children ages 5 to 14. Late last year, BioMarin reported that those in the open-label long-term extension of the Phase 3 study maintained an increase in annual growth velocity through the second year of continuous treatment. In children treated with the BioMarin drug, the cumulative height gain over the study’s two years was 3.52 cm more than that of untreated children.

The extension study that is continuing to follow children who participated in the clinical trials has yet to reach the five-year mark. But BioMarin said that so far, the growth rates have been sustained and adverse events have been mild. The most common problems were injection site reactions and low blood pressure. BioMarin added that the adverse events reported did not include disproportionate bone growth or other bone problems, and there is no evidence so far of accelerated bone age or negative changes in bone mineral density.

According to BioMarin, an estimated 11,000 children in Europe, the Middle East, and Africa have achondroplasia and could be eligible for treatment with Voxzogo. The drug is still under FDA review. The U.S. agency has set Nov. 20 as the target date for a regulatory decision.

Incyte, Morphosys cancer drug gets European approval in lymphoma

In other European Commission drug approval news, Incyte and Morphosys were granted conditional marketing authorization for tafasitamab as a treatment diffuse large B-cell lymphoma (DLBCL). The decision for the antibody drug covers adults whose disease has relapsed or has not responded to earlier treatment, and who are not eligible for a stem cell transplant. Approval of the drug, which will be marketed in Europe under the name “Minjuvi,” covers its use in combination with Bristol Myers Squibb cancer drug lenalidomide, followed by Minjuvi as a monotherapy.

European approval of Minjuvi comes about one year after the FDA awarded accelerated approval to the drug. Incyte and MorphoSys share rights to the drug; the partners co-market the therapy in the U.S. under the name “Monjuvi.” Wilmington, Delaware-based Incyte holds exclusive commercialization rights to the drug outside of the U.S.

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