Concert Pharmaceuticals will see if investors are ready to buy in to the biotech's approach to improving therapies with its deuterium-tweaking technology. The Lexington, MA-based biotech has filed for a $75 million IPO. Under CEO Roger Tung, Concert has struck a series of collaborations, including a $300 million deal with Celgene ($CELG) to improve its cancer and anti-inflammatory drugs. Concert's business plan has relied on partnerships to help fund the company as it pursues a mid-stage program for its own in-house program, CTP-499 for diabetic kidney disease. And it's banking on a simple scientific concept: proposing to stabilize drugs with deuterium in such a way as to redefine compounds, making them less threatening on the side-effect front and more promising in terms of efficacy. Concert plans to list as $CNCE. S-1