Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Geron (NASDAQ:GERN), a clinical-stage biopharmaceutical company focused on developing therapies to treat hematologic malignancies, skyrocketed as much as 33% after announcing that the Food and Drug Administration had removed the partial clinical hold on imetelstat in its myelofibrosis investigator-sponsored trial.

So what: As a refresher, the partial clinical hold was put in place by the FDA in March due to concerns of imetelstat-driven liver damage. Per its press release, Mayo Clinic investigator Dr. Ayalew Tefferi needed to supply the FDA with additional safety information regarding imetelstat as a treatment for myelofibrosis. With that being done and the partial hold now lifted, its IST can continue as planned. However, Geron notes that the FDA still has a full clinical hold in place for its polycythemia vera and multiple myeloma indications.

Now what: I'm not too shocked with today's press release as imetelstat had delivered meaningful clinical responses in its myelofibrosis investigator-sponsored trial which likely merited further research. In fact, this was right along the lines of what I expected would happen. However, we have to consider that imetelstat is Geron's only clinical compound, so if it continues to experience safety issues, is unable to get its full clinical hold removed for its two additional indications, or it simply fails to meet its primary endpoint in trials, then Geron's share price is likely going to be crushed. Companies with single drug clinical pipelines are far too risky for my blood and I'd suggest you also consider looking elsewhere for investing ideas.