There are continuing concerns being heard that the biotech bubble could be coming to an end, but last year's results appeared strong.

As far as a possible bubble, on March 21 there was a drop in the SPDR S&P Biotech ETF. On four straight trading days, the SPDR S&P Biotech ETF was down 9.3 percent, according to the Motley Fool.

“We've been given plenty of warning signs for months that a sizable correction could be in the offing in the biotech sector, but investors have largely ignored those warnings,” the Motley Fool added. “Now it appears a biotech correction could be rearing its head.”