Shares of Threshold Pharmaceuticals (NASDAQ:THLD) have fallen off a cliff today, trading about 20% lower following the release of additional data regarding its Phase 2b trials of TH-302.

It's a tale of two endpoints for Threshold investors, with the company reiterating positive data on progression-free survival and introducing less-than-enthusiastic findings on overall survival. Patients receiving a combination of TH-302 and gemcitabine have displayed a 63% improvement in progression-free survival relative to a control group receiving gemcitabine alone. In terms of overall survival, data was less positive for TH-302, with the cohort given the highest dosage of TH-302 seeing median survival 33% longer than the control group.

The progression-free numbers are old news for Threshold shareholders. The company released this data back in late February, so it was the overall survival numbers that had investors on the edge of their seats. The data wasn't nearly as positive as hoped, hence the negative reaction today.

Context is key
Before investors head to the exits, it's important to keep this move in perspective. Here's a look at where Threshold shares stood for the year before today's announcement:

Charts

THLD Total Return Price data by YCharts.

Today's action serves as a mere bump in the road for the stock relative to where it started the year. Pancreatic cancer remains one of the deadliest forms of cancer, given how late it is typically discovered. According to a recent report by the Pancreatic Cancer Action Network, pancreatic cancer has a five-year survival rate of 6%. Given that backdrop and the positive data supporting progression-free survival, TH-302 still appears to have life heading into Phase 3 trials.

While today's announcement has some investors reassessing the odds of Threshold's success with TH-302, the true long-term investor shouldn't be swayed by the emotions today's volatility could engender. Removing emotion from the investment process is one key to success for investors looking for a fruitful retirement. For more ideas and guidance, make sure to check out the Fool's special free report entitled "3 Stocks That Will Help You Retire Rich." To claim an instant copy of this report, click here now.

Brenton Flynn has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.