Four medical stocks were Sector Leaders in Friday’s edition, the most for any of IBD’s 33 sectors. That’s a show of strength for the sector, which has been among the best since the S&P 500 bottomed on Aug. 7. The four — all of them drug developers — are near new highs, with three near possible new entries. Alexion Pharmaceuticals (ALXN) has been basing the longest — since late February.