GSK, Sphera Global and Temasek-backed gene therapy developer Orchard Therapeutics raised $200m in an offering that could possibly close at $230m.

Orchard Therapeutics, a UK-based gene therapy developer which counts pharmaceutical firm GlaxoSmithKline (GSK) as its second largest investor, floated in the US on Wednesday in a $200m initial public offering.

The IPO consisted of almost 14.3 million American depositary shares (ADSs), each representing a single ordinary share, issued on the Nasdaq Global Select Market and priced at $14 each. It had set a $14 to $16 range for 13.3 million ADSs last week.

Founded in 2015, Orchard is working on ex vivo gene therapies based on an individual patient’s own haematopoietic stem cells in order to treat immune system deficiencies, neurometabolic disorders and hemoglobinopathies – genetic defects that affect the haemoglobin molecule.

The company intends to channel $65.8m of the IPO proceeds into registrational trials and regulatory approval submissions for three product candidates, establishing clinical proof of concept for a fourth and progressing three other preclinical candidates.

A further $84.5m will support design and construction of a dedicated manufacturing plant while $17.8m is earmarked for the commercialisation of Strimvelis, a treatment for the immunodeficiency disorder ADA-SCID that has been available in the European Union since 2016.

Orchard raised $150m in an August 2018 round led by Deerfield Management and backed by healthcare management services firm Sphera Global Health Care and Medison Ventures, the corporate venturing arm of medical marketing firm Medison, that took its total funding to $290m.

The round also included Temasek, Baillie Gifford, RA Capital Management, Venrock, Cormorant Asset Management, ArrowMark Partners, Driehaus Capital Management, Ghost Tree Capital, RTW Investments, Foresite Capital, Perceptive Advisors, Cowen Healthcare Investments and Agent Capital.

Baillie Gifford and ORI Capital co-led the company’s $110m series B round in December 2017, investing alongside F-Prime Capital, part of financial services and investment group Fidelity, as well as Temasek, Cowen Healthcare Investments, RTW, Agent Capital, Juda Capital, Pavilion Capital, 4Bio Capital and UCL Technology Fund.

GSK subsequently secured a 19.9% stake in Orchard as part of an April 2018 licensing agreement that had been diluted to 17.9% pre-offering and 14.8% post-IPO. F-Prime’s stake was cut from 29.3% to 24.3% while the other notable investors were Deerfield (5.5% post-IPO) and Scottish Mortgage Investment Trust (4.6%).

The IPO price gave Orchard a market capitalisation of approximately $975m. Its shares opened at $16.45 yesterday and closed at $13.93 yesterday.

JP Morgan, Goldman Sachs and Cowen are joint book-running managers for the IPO while Wedbush PacGrow is co-manager. The underwriters have the option of buying more than 2.1 million additional shares, which would lift the size of the offering to $230m.