ImmunoCellular announced Wednesday that it will suspend the phase 3 trial for a vaccine that was developed to treat a specific fast-growing brain tumor.

The Calabasas biotechnology company said it was unable to secure sufficient financing to complete the clinical trial for its lead product. Instead, the company will seek a collaborative arrangement or acquisition of the vaccine program. A Phase 3 clinical trial is the last round of tests before a drug is approved and marketed.

This announcement comes after ImmunoCellular released less than stellar data from its phase 2 clinical trials in 2014. At the time, the vaccine, called ICT-107, prolonged participating patients’ survival for only two to three months, which was not statistically significant. Patients diagnosed with the brain tumor called Glioblastoma multiforme or GBM have a median survival of 15 months.

Shares of ImmunoCellular (IMUC) on Wednesday closed down 4 cents, or more than 4 percent to 83 cents on the New York Stock Exchange.