The U.S. has fast tracked the approval of a new cancer drug developed in Australia, ABC News reported Tuesday. Venetoclax, a Melbourne-developed drug that targets cancer-causing biological factors like cell-structure mutations, has been given the green-light. However, the new drug has not been approved in Australia as of yet.

The new cancer drug was tested on several cancer patients during a research study at the Peter Maccallum Cancer Center in Victoria, Australia. Upon completion of the trial, nearly four out of five patients had a positive result, and one out of five patients’ cancer went into complete remission while using the drug.

“Cells, when they are born, are destined to die and cancer cells and particularly leukemia cells delay that death by using a protein called BCL2 that stops the normal time of death," John Seymour, who helped oversee the trial, told reporters. “Venetoclax works by specifically blocking the action of the BCL2 and allows the cells to die in the way that they were destined to.”

One of the patients, Robert Oblak, who happened to be the “eleventh person in the world” to use Venetoclax, said that his results with the drug were “amazing.”

“It causes no side-effects. Nothing, absolutely nothing,” said Oblak, whose recurrurance of chronic lymphocytic leukemia went into remission within a year following his participation in the trial. “Quite amazing. So even when it’s killing cells, you feel great.”

According to the Leukemia & Lymphoma Society, an estimated 1,237,824 people in the U.S. were suffering from or in remission from leukemia, lymphoma or myeloma in 2015. 171,550 people are expected to be diagnosed with these specific cancers in 2016.

It is unknown when Venetoclax will be available for Americans suffering from leukemia.