After MEI Pharma announced that its cancer drug Pracinostat has not derived good results in a phase-two clinical trial, the company's shares lost more than two-thirds of their value on Monday.

Experts shared that the San Diego biotech's shares closed at $1.93, down $4.37, or 69%. On Friday, the company's shares closed at $6.30.

The company said that the drug was not able to provide complete remission in combination with another cancer drug in comparison to other cancer drug alone. Pracinostat was tested along with azacitidine on a blood cancer called myelodysplastic syndrome.

It is a syndrome in which blood cells in the bone marrow are not able to grow. In the trial, which was a double-blind, placebo-controlled one, 102 patients were enrolled at 19 different sites across the United States.

Concerns have been raised over the future of the drug, which is also being tested for another rare blood cancer. Roth Capital's Joseph Pantginis said, "The risk profile for pracinostat has significantly increased and one potential scenario is the discontinuation of the drug's development".

The failure of the study has now casted doubts on a late-stage study of the drug in acute myeloid leukemia (AML) patients, which is scheduled to start in mid-2015.

In a press release, Daniel P. Gold, the company's president and CEO, said the company is thinking its options with the drug. Gold said they are looking for potential signs of drug's benefit.

He affirmed that they are quite disappointed with the results of the phase two clinical trial. But they are now carefully assessing the complete data set and subsets from the study. At this point of time, several aspects are being considered like duration of response, event and progression free survival and overall survival.

All these factors will have an important impact on the future development path of the drug.