NEW ORLEANS – The immunotherapy drug blinatumomab improves survival as a first-line treatment in certain younger adult patients with B-lineage acute lymphoblastic leukemia, investigators have found. The extremely expensive drug is currently Food and Drug Administration approved for B-lineage ALL in relapsed/refractory cases.
“We feel that this represents a new standard of care for these patients and should be incorporated into their standard therapy,” said lead author and hematologist Mark R. Litzow, MD, of Mayo Clinic in Rochester, Minn., in a news briefing at the annual meeting of the American Society of Hematology.
Dr. Mark R. Litzow, MD
B-lineage ALL, also known as B-cell ALL, represents 75% of cases of the blood cancer in adults according to the Leukemia & Lymphoma Society. It occurs when there’s an overgrowth of immature white blood cells known as B-cell lymphoblasts. “These are the blast cells that don’t function well and cause these patients to develop infections and bleeding,” Dr. Litzow said.
Treatments include chemotherapy and stem-cell transplants. Blinatumomab, a bispecific T-cell engager molecule, is FDA approved for patients with relapsed/refractory B-lineage ALL and those with morphologic complete remission who still have measurable residual disease (MRD).
As the new study notes, some patients who undergo chemotherapy and reach remission have poor survival outcomes even when there’s no sign of MRD. “Even though we can’t find leukemia in the patients’ bone marrow, it’s still hiding there,” Dr. Litzow said.
The new phase 3, randomized trial aims to determine if adding blinatumomab (Blincyto) to first-line chemotherapy improves outcomes. The drug “brings a normal T cell, part of the immune system, in proximity to a leukemia plasma cell and kills it.”
For the study, researchers from 2013 to 2019 recruited 488 patients aged 30-70 years with newly diagnosed BCR::ABL1 negative B-lineage ALL (median age = 51). The subjects underwent chemotherapy, and then were “randomized to receive an additional four cycles of consolidation chemo or two cycles of blin [blinatumomab] for 28 days each cycle followed by three cycles of consolidation chemo, another 4-week cycle of blinatumomab (third cycle of blinatumomab) followed by an additional cycle of chemo and then a fourth cycle of blinatumomab (step 3),” the researchers reported. “Following completion of consolidation chemo +/– blin, patients were given 2.5 years of POMP [prednisone, vincristine, 6-mercaptopurine, and methotrexate] maintenance therapy timed from the start of the intensification cycle (step 4).”
There were 112 patients in each group. Among MRD-negative patients, 56 patients died – 17 in the blinatumomab arm and 39 in the control arm at the third interim efficacy analysis. At a mean follow-up of 43 months, median overall survival for patients in the blinatumomab arm was not reached vs. 71.4 months in the control group (hazard ratio, 0.42, 95% confidence interval, 0.24-0.75; P = .003).
“The patients that got blinatumomab plus chemotherapy had an improved survival over those that got the standard chemotherapy,” Dr. Litzow said.
Dr. Litzow didn’t discuss the drug’s expense in his presentation. According to a 2019 report, when a daily vial of blinatumomab cost $3,464-$3,815, a treatment course of five month-long cycles could run to $535,000. According to drugs.com, the cost now is $4,740 per vial – more than $660,000 for five cycles.
In an interview, Cleveland Clinic hematologist/oncologist Anjali Advani, MD, said the study is “groundbreaking and one of the most exciting studies to come along in the acute lymphoblastic leukemia field.”
The trial “is one of the first studies to show improvement in outcome in a randomized manner with the addition of a novel agent,” she added. “This will change our standard of care for these patients.”
The National Cancer Institute funded the trial and drug manufacturer Amgen provided the medication and support through a cooperative research and development agreement.
Dr. Litzow discloses relationships with Actinium, Jazz, Syndax, Novartis, Astellas, Amgen, Abbvie, Pluristem and Biosight. Other authors have various disclosures with multiple drugmakers. Dr. Advani discloses relationships with Amgen, Jazz, Nkarta, Taiho, Beam, GMI, Kura, Pfizer, OBI, Incyte, Kite, ImmunoGen, GlycoMimetics, SGN, MacroGenics, and Servier.