Pfizer, the US pharmaceutical behemoth, announced on Thursday the completion of its acquisition of the cancer-focused biotechnology company Seagan Inc. Pfizer completed the acquisition for $229 per share, for a total enterprise value of approximately $43 billion. Pfizer said Seagan’s four approved cancer therapies will bolster its oncology portfolio, which now includes over 25 approved medicines and biosimilars. As previously disclosed, to address US Federal Trade Commission concerns, Pfizer has chosen to irrevocably donate the rights of royalties from sales of the immuno-oncology drug Bavenci…