Shares in Cardio3 Biosciences SA performed strongly on their first day of trading, following a July 4 initial public offering (IPO) on the NYSE Euronext exchanges in Brussels and Paris that raised €23 million (US$29.6 million).

The Mont-Saint-Guibert, Belgium-based stem cell therapy developer priced the offering at €16.65 per share, at the bottom of the indicative price range of €16.65 to €19 per share it set in advance of the book-building process.

That price implied a valuation of €102 million, but the stock (BRUSSELS, PARIS:CARD) opened at €17.64 Friday, the first day of trading, and peaked at €19.99 by 12:20 p.m. local time, a gain of 20 percent on the IPO price.

The pricing strategy was obviously informed by a desire to ensure that investors saw an immediate return on their participation in the offering. But it was not the only factor.

"The most important element is we had some very strategic funds that came in with significant offers that were slightly above the floor price. We felt that it was very important to have them," Cardio3 CEO Christian Homsy told BioWorld Today.

Cardio3 partially exercised an increase option of 195,000 shares it had built into the original offer of 1.3 million shares. It ultimately sold 1,381,500 shares, and it currently has a total of 6,125,567 shares outstanding.

Kempen & Co N.V., of Amsterdam, the Netherlands, has received an overallotment option of another 207,225 shares on behalf of the joint bookrunners, which, if exercised, would increase the total proceeds to €26.45 million.

Cardio3 is using the cash to complete a Phase III trial of its lead therapy, C-Cure, in 240 patients with ischemic heart failure.

Primary endpoint data from the trial are due, on current forecasts, by the end of 2015, with interim data due by late 2014. Before then, the company aims to secure authorization for a U.S. Phase III trial of C-Cure.

The therapy is based on cardiopoiesis technology developed by Atta Behfar and Andre Terzic, at the Mayo Clinic, in Rochester, Minn. It consists of an infusion of autologous bone marrow-derived mesenchymal stem cells, which are reprogrammed ex vivo to become "cardiopoietic" or cardiac progenitor cells, using a cocktail of growth factors.

Cardio3 has so far kept all options on the table regarding the commercialization of C-Cure. The therapy, if successful, would be aimed at key opinion leaders operating in specialist cardiac centers. There are about 2,200 such facilities between Europe and the U.S., which, Homsy said, could be addressed by around 200 sales reps. "That is perfectly doable for a small company."

The company has developed a proprietary catheter, C-Cath, to ensure optimal uptake and retention of the reprogrammed progenitor cells it administers to patients, via intramyocardial injection. The company is also seeking to commercialize that innovation separately from C-Cure.

It has already gained a European approval, in the form of a CE mark, and it is currently seeking partners to take it forward. It is under review in the U.S.

The IPO represents the first dual listing of a biotechnology firm on the Brussels and Paris Euronext exchanges and just the second European biotech IPO this year, following Lyon, France-based Erytech Pharma SA's offering in May, which raised €16.7 million. That stock (PARIS:ERYP) is currently trading at €11, slightly below the IPO price of €11.60.

The biggest European biotech IPO of this year happened in the U.S. Prosensa Holding B.V., of Leiden, the Netherlands, grossed $78 million on Nasdaq, by selling 6 million shares priced at $13 each.

Shares in Cardio3 Biosciences ended their first day of trading at €18.89, up 13.5 percent on the IPO price.

A blog post published Monday by Forbes claimed a conflict of interest on the part of clinical investigator William Wijns, co-director of the Cardiovascular Center in Aalst, Belgium, for failing to disclose, in a recent paper in the Journal of the American College of Cardiology (JACC) reporting data from a Phase II trial of C-Cure, his alleged receipt of shares in the company's IPO.

However, a spokesman for Cardio3 told BioWorld Today that Wijns had not, in fact, received any such shares: "This investment was made in a personal capacity and after the JACC paper had been submitted, reviewed and published. The disclosures made in this respect in the JACC publication are thus appropriate given the timing of Professor Wijns share purchase."

The paper, titled "Cardiopoietic Stem Cell Therapy in Heart Failure: The C-Cure (Cardiopoietic stem Cell therapy in heart failURE) Multicenter Randomized Trial With Lineage-Specified Biologics," appeared in the June 11, 2013, issue of JACC, but had been published electronically on April 10.