A new vaccine helped leukemia patients fight their cancer and stay in remission for an average of almost five years, according to new study.

Patients who had undergone chemotherapy to treat acute myeloid leukemia received vaccines personalized to their own form of the disease, to stimulate a potent immune attack against it and reduce the likelihood of their cancer returning.

For the trial, people over the age of 60 were particularly targeted, as only 15% to 20% of this age group remains leukemia-free for two years, on average, after receiving chemotherapy.

During the study, published in Science Translational Medicine on Wednesday, the vaccine was shown to more than double this average remission period for the majority of people involved in the trial.

Acute myeloid leukemia causes a person's bone marrow to make abnormal versions of either their white blood cells, red blood cells or platelets, which are responsible for blood clotting. As abnormal versions of these cells begin to grow, they dominate the bone marrow and blood, leaving less room for healthy white cells, red cells or platelets.

Although chemotherapy kills these abnormal cells, most patients eventually relapse, often with a resistant form of the cancer, according to the researchers. Even in patients under the age of 60, the five-year survival rate is just 34%, informs CNN.