The hot market for life sciences IPOs shows signs of cooling. While companies continue to add themselves to the queue, the fever pitch of biotech IPOs has abated. During the second week of November, one therapeutic and one medical device company completed initial public offerings while three companies, CardioDx, Celladon, and Xencor, postponed their offerings citing poor market conditions.

The possible reasons for the cool down are varied. Some have said that the best companies have already gone public and the ones in the queue are not as interesting to investors, but this seems disingenuous as the JOBS Act allows all these companies to file confidentially and test the waters before announcing their intention publicly.

Another reason may be that investors are realizing the risks inherent in biotech offerings as seen in clinical and regulatory setbacks of therapies once thought to hold great promise. Just this week shares of Sarepta Therapeutics dropped 64 percent after the FDA told the company its intention to file a new drug application for eteplirsen as a treatment for Duchenne muscular dystrophy was premature. And newly public Epizyme fell 37 percent after reporting so-so results from a small early- stage trial of EPZ-5676 to treat adults that had already been treated with other drugs for advanced hematological cancers. The first human trial of the genetically targeted drug showed effects “consistent with the genetically defined therapeutic mechanism of action,” said the company.

After the third quarter of 2013 when 16 life sciences companies priced at an average 2 percent below their target midpoint and often popped in the first days of trading, the nine companies that have completed initial public offerings so far during the fourth quarter are pricing an average 18 percent below their target midpoint.

Not only has the pace of offerings slowed, but the performance of the 48 companies that have completed IPOs on U.S. exchanges during 2013 has dropped an average of 28.8 percent over the last two weeks, although these companies are still up 29.5 percent as a group compared to their initial offering price.

The two IPOs in the past week were completed at the opposite ends of the spectrum. Medical device maker Tandem Diabetes Care raised $120 million through an initial public offering of 8 million shares at $15 per share, pricing at the top of its range. The San Diego-based company makes a touch screen insulin pump for continuous glucose monitoring of diabetes patients, which recently received U.S. regulatory clearance. Tandem reported a net loss of $26.5 million in the first six months of 2013, and sales revenue of $11 million.

Cardiorenal drug developer Relypsa raised $75 million through its initial public offering but it had to cut its price twice to $7 a share from the original target midpoint of $17.50. The company’s lead product candidate, patiromer, is in late-stage development as a treatment for hyperkalemia, a life-threatening condition defined by abnormally high levels of potassium in the blood. The Redwood City, California-based company has incurred more than $223 million in losses since it its founding in 2007, according to its regulatory filing.

Tandem ended the week up 45.6 percent while Relypsa’s shares were up 9.7 percent in their first day of trading. There are still 13 companies in the IPO queue that have not postponed their plans, with five of these companies added to the queue in the last two weeks.

While the momentum has been tempered for life sciences initial public offerings, there’s should still be investor appetite for these issues as long as the biotech sector continues to lead the markets. The Burrill Biotech Select Index, up 53 percent since the beginning of the year, continues to beat the major indices in year-to-date performance.