The agency plans to hold an advisory committee meeting because studies have found that high dosages of Amgen’s Aranesp and Epogen and Johnson & Johnson’s Procrit boost the risk of heart attacks, strokes and blood clots in anemia patients with kidney disease. The purpose of the meeting, which hasn’t been scheduled yet, is to determine the appropriate dosages.

Known as erythropoiesis-stimulating agents, or ESAs, the drugs boost hemoglobin levels in anemics, but the drugmakers have been plagued by cardiovascular risks that caused sales to decline. As it turns out, using large doses to cause hemoglobin to return normal levels may also increase the risk of heart attacks and strokes, instead of lowering the risk.

“Randomized trials have endeavored to show that using ESAs to raise hemoglobin concentration to higher targets improves clinical outcomes,” Bob Temple, deputy director for clinical science at the FDA’s Center for Drug Evaluation and Research, and his colleagues wrote in a commentary in this week’s edition of The New England Journal of Medicine. “Unfortunately and unexpectedly, all results have suggested the opposite.”

UPDATE: One analyst says….

In an investor note today, Joel Sendek, an analyst at Lazard Capital Markets, writes: “In our opinion, the tone of the FDA’s editorial does not bode well for Amgen’s ESA franchise and could cast a cloud over continued broad ESA use. The authors demand clear clinical evidence of optimal hemoglobin targets, a dosing algorithm, and monitoring approach for patients with CKD-related anemia. We find the FDA’s method of communicating its concerns, via an NEJM article rather than just scheduling the advisory committee, as a clear sign that ESAs are a high-priority issue, and the FDA’s perspective is clear. We view the FDA’s editorial in the NEJM as a method of applying pressure on Amgen to conduct large-scale, expensive clinical trials directly assessing for efficacy and safety of ESAs, which were assessed as part of the original NDA submission, as well as pressuring physicians directly to decrease ESA use.”