(Reuters) - The U.S. health regulator on Friday approved the expanded use of BioMarin Pharmaceutical's once-daily injection to treat children under the age of 5 with the most common form of short-limbed dwarfism.

The drug, branded as Voxzogo, in 2021 was the first therapy to be greenlighted by the Food and Drug Administration (FDA) for treating the genetic disorder, known as achondroplasia, in children aged five and older under the FDA's accelerated approval pathway.

Achondroplasia, a form of disproportionate short stature caused by a mutation in a gene, occurs in about one in every 25,000 newborns.

The company is betting on Voxzogo and its recently approved gene therapy, Roctavian, for treating an inherited bleeding disorder to drive the company's growth in the next few years.

The FDA's decision on the expanded use was supported by trial data that showed the therapy showed a similar safety and efficacy profile in children under 5 years of age, as compared to those 5 years and older.

Guggenheim Securities analyst expects the expanded label in the United States to add 800 additional patients for Voxzogo and fairly assist to top-line growth for 2024.

Voxzogo, introduced in 2021, bought in sales of $169.2 million in 2022. This year, the company increased Voxzogo's sales forecast twice, and expects sales of $400 million to $440 million in 2023.

BridgeBio Pharma's investigational therapy, infigratinib and Denmark-based Ascendis Pharma's dwarfism drug TransCon CNP, are potential rivals in development.

Voxzogo, approved in Europe, Australia and Brazil for children aged two and above and in Japan for use in children of all ages, is also under review in Europe to expand the injection's use in children aged four months and older.

(Reporting by Pratik Jain and Khushi Mandowara in Bengaluru; Editing by Shailesh Kuber)