DUBLIN – Swedish start-up Cantargia AB is seeking about SEK44.1 million (US$5.4 million) in an initial public offering (IPO) on the Nasdaq OMX First North exchange, the Nordic region's junior exchange, in order to take forward a new therapeutic concept in cancer.

The IPO comprises 5.8 million shares, priced at SEK7.60 per share. The subscription period runs from Jan. 27 through Feb. 12. Investors who participate in the transaction will also receive warrants that will enable them to participate in a series of follow-on offerings planned for 2016, through which the company plans to raise an additional SEK55.1 million.

"Hopefully, if we're doing things right, they'll be motivated to continue, and we won't have to spend a lot of energy during a critical part of the development process," Cantargia CEO Göran Forsberg told BioWorld Today.

Lund-based Cantargia is building on the research of co-founders Thoas Fioretos and Marcus Järås, both of Lund University, who identified interleukin-1 receptor accessory protein (IL1RAP), a component of the IL-1 receptor complex, as a novel target in leukemia.

"The clinical problem you have in leukemia is you can treat patients – especially with acute myeloid leukemia – with chemotherapy, and that's quite effective on the mature tumor cells, but the patients always relapse," Forsberg said. That's because surviving cancer stem cells can continue to feed the cancer.

Fioretos and Järås identified IL1RAP through comparative gene expression analysis of cells that were positive or negative for the Philadelphia chromosomal translocation, a pathological hallmark in chronic myeloid leukemia (CML). The protein was up-regulated in CD34-positive CML cells because of the expression of the BCR/Abl1 tyrosine kinase activity associated with the Philadelphia chromosome. Cord blood CD34-positive cells transformed by a retrovirus carrying the BCR/Abl1 gene also overexpressed IL1RAP.

They found that CML stem cells destined to be either positive or negative for the Philadelphia translocation could be distinguished on the basis of their IL1RAP expression profiles. They also established that IL1RAP is expressed in monocytes but is absent or present at a low level in bone marrow progenitor cells and in mature cells, suggesting it may be a safe target for therapy. Those findings were published in the Sept. 14, 2010, issue of the Proceedings of the National Academy of Sciences – in a paper, titled "Isolation and killing of candidate chronic myeloid leukemia stem cells by antibody targeting of IL-1 receptor accessory protein" – and form the basis of patent application filings with a priority date of Aug. 29, 2009.

Since then, the company has developed a humanized antibody that has achieved in vivo proof of concept. "We reduce the tumor burden, and we can see some sort of survival signal in some models," Forsberg said. In addition to hematological malignancies, emerging evidence indicates that IL1RAP also functions as a survival signal in some solid tumors.

The company is still almost two years from the clinic – it has to complete GMP process development and preclinical toxicity studies before human trials. "The bottleneck right now is to get the production up and running," Forsberg said. Its first-in-man study will be an all-comers trial in cancer patients overexpressing IL1RAP. Data from that study will help the company determine its lead indication for a phase II trial.

Another Nordic firm, cancer therapy specialist Nordic Nanovector ASA, also unveiled plans this week to seek a public listing. The Oslo, Norway-based company, which is developing antibody-radionuclide-conjugates, said it expected to commence pre-marketing activity during the current quarter.