(Reuters) -BioAge Labs is eyeing a valuation of up to $639.7 million in its upsized initial public offering in the United States, the obesity drug developer said on Wednesday, in a sign of strong demand from investors.

Booming demand for Eli Lilly’s Zepbound and Novo Nordisk’s Wegovy has caught the attention of investors, drawing in fresh capital towards other obesity drug developers.

Richmond, California-based BioAge is seeking to raise as much as $199.5 million by offering 10.5 million shares at $17 to $19 each.

It had earlier planned on offering 7.5 million shares at the same price range.

The IPO comes more than a week after a trio of drug developers together raised more than $700 million in their upsized offerings and made strong market debuts, underscoring investors’ enthusiasm in the biotech sector.

MBX Biosciences, which is developing therapies that target endocrine and metabolic disorders, including diabetes and obesity, went public earlier this month. Its shares are up 43.7% from the IPO price, as of last close.

BioAge’s lead drug, azelaprag, is being developed to treat obesity, in combination with GLP-1 agonists such as Eli Lilly’s Zepbound and Novo Nordisk’s Wegovy.

Affiliates of existing investor Sofinnova Venture Partners are expected to invest up to $1.4 million directly in the public offering, BioAge said.

Besides, the investment firm is now expected to purchase shares worth about $10.6 million in a concurrent private placement at the IPO price, lower than its prior expectation of about $15 million.

Since its inception in 2015, BioAge has raised more than $300 million to date from investors including venture capital firms a16z and Khosla Ventures, investment manager RA Capital and healthcare giant Kaiser Permanente.

BioAge will list on the Nasdaq Global Market under the symbol “BIOA”.

Goldman Sachs, Morgan Stanley, Jefferies and Citigroup are the underwriters for the offering.

(Reporting by Arasu Kannagi Basil in Bengaluru; Editing by Shilpi Majumdar)