InfraReDx takes $17M for arterial-plaque detection — InfraReDx, a Burlington, Mass., developer of diagnostic systems that detect arterial plaque, raised $17 million in a third funding round, VentureWire reports. Sanderling Ventures led the round, joined by new and previous individual investors.

InfraReDx previously planned to raise up to $40 million in order to support expected commercialization of its near-infrared device, which can identify buildups of arterial plaque that can rupture and lead to heart attacks (see our coverage). The test, however, requires a minimally invasive procedure in which the device is threaded into a patient’s circulatory system, making the InfraReDx device primarily useful for preventing second heart attacks in patients who are being treated for their first.

The company submitted its device for FDA approval in October, and is planning on a limited rollout if the device is cleared this quarter, as InfraReDx expects.

Cancer-drug developer Serenex sells out to Pfizer for undisclosed sum — Durham, N.C.-based Serenex, a biotech working on drugs that could be useful in cancer and other conditions, agreed to be acquired by Pfizer. The release is here. The companies didn’t disclose terms of the deal.

Serenex claimed to have a technology for developing drugs against a wide variety of cellular proteins, but in practice Pfizer appears to have been most interested in drugs that inhibit heat-shock protein 90, or Hsp90, a molecule that regulates other proteins crucial to cellular growth and survival. The startup’s lead compound, SNX-5422, is in early-stage, phase I testing against a variety of tumors.

Pfizer, of course, will also walk away with Serenex’s drug-discovery technology and a library of other drug candidates. Notably, however, Pfizer did not buy the startup’s leading experimental drug, SNX-1012, which is being tested against oral mucositis, a common side effect of chemotherapy. That, of course, leaves open the possibility that Serenex management — or someone else — will try to form a new company around that drug. This sort of strategy is increasingly popular; for my take on it, see here.

Life-sciences fund Longitude Capital raises $95M — Menlo Park, Calif.-based Longitude Partners, a spinout of Pequot Ventures, raised $95 million of an anticipated $325 million first fund, VentureWire reports. The fund will invest in biotech, medical-device and drug-development startups.