Rubius Upsizes IPO and Hauls in $241M for Red Blood Cell Therapies

Xconomy Boston — 

Rubius Therapeutics has joined the parade of biotech companies going public, raising a whopping $241.1 million to support its approach of engineering red blood cells into off-the-shelf treatments for disease.

Late Tuesday night, Cambridge, MA-based Rubius priced its offering of 10.4 million shares at $23 apiece. The company had initially planned to sell 9.5 million shares in the range of $20 and $22. In a year marked by a pronounced uptick in IPO activity, the Rubius IPO ranks as the biggest biotech IPO so far in 2018, according to a review of healthcare IPOs listed at Renaissance Capital. Rubius shares are expected to begin trading on the Nasdaq exchange Wednesday under the stock symbol “RUBY.”

Rubius is engineering red blood cells into cell therapies that could treat rare diseases, cancer, and autoimmune disorders. The company engineers these cells so that they carry therapeutic proteins inside the cell or on its surface. Torben Straight Nissen, Rubius’ president, told Xconomy last year that red blood cells offer the potential for a long-lasting treatment because these cells naturally circulate in the blood stream and have a life span of about 120 days.

Unlike the T-cell therapies for cancer that are currently available on the market, which are made from a patient’s own cells, the Rubius therapies would be made from cells harvested from donors and used in any patient. The concern about such “off-the-shelf” treatments is the potential for an immune system response against the engineered cells. Rubius aims to avoid that adverse reaction by fashioning its cells from O-negative blood, the blood type that is a universal donor.

Rubius does not yet have any data from tests of its cell therapies in humans. A filing to start clinical trials for lead drug, RTX-134, is expected in the first quarter, according to the Rubius prospectus. That drug will be tested as a treatment for phenylketonuria (PKU), a rare inherited disorder characterized by the buildup in the body of phenylalanine, an amino acid.

Rubius plans to use $95 million of the IPO proceeds to purchase and renovate a facility to manufacture its red blood cell therapies, according to the filing. Another $42 million will be used to bring RTX-134 through a Phase 1/2a clinical trial. And $176 million of the proceeds will fund additional research and development, including the preclinical work needed to advance other therapeutic candidates into clinical testing.

Since Rubius was founded in 2013 by venture capital firm Flagship Pioneering, the company has raised approximately $240 million in financing, including a $100 million funding round a little more than four months ago.

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