Phase II BLAST Study shows median overall survival of 36.5 months in patients with minimal residual disease positive acute lymphoblastic leukemia

Amgen has announced the five-year overall survival (OS) analysis from the single-arm, Phase II BLAST study that evaluated Blincyto (blinatumomab) in patients with minimal residual disease (MRD)-positive acute lymphoblastic leukemia (ALL). The study found that with a median follow-up of 59.8 months, the median OS for Blincyto -treated patients was 36.5 months (95 percent CI: 22 months - not estimable [NE]). More than half of patients who achieved a complete MRD response following the first cycle of Blincyto treatment were alive at five years.

These results from the largest prospective trial ever conducted in MRD-positive ALL were presented during an oral presentation at the 24th Annual Congress of the European Hematology Association (EHA) in Amsterdam .

"As the only CD19-targeted immuno-oncology therapy with five-year survival data, Blincyto continues to demonstrate compelling results for ALL patients," said David M. Reese , M.D., executive vice president of Research and Development at Amgen . "We are proud of the science behind our BiTE technology. These data in an MRD-positive ALL patient population give us increased confidence in the clinical benefit of Blincyto especially when these patients are treated earlier."

The Phase II open-label BLAST study enrolled 116 patients with MRD-positive Philadelphia chromosome-negative (Ph-) B-cell precursor ALL in first or subsequent complete hematologic remission after at least three intensive chemotherapy blocks of treatment. Of the 116 enrolled patients, OS was evaluated for 110 patients with less than five percent leukemic blasts, including 74 patients who received hematopoietic stem cell transplantation (HSCT) in continuous complete remission (CCR) after Blincyto treatment.

Results presented at EHA showed that in 84 patients who achieved a complete MRD response (had no measurable MRD), median OS was not reached (95 percent CI: 29.5 months - NE) compared to 14.4 months for those who had measurable MRD (n=23; 95 percent CI: 3.8 - 32.3 months). Among patients with MRD in first complete remission (CR1), median OS was not reached for those who achieved a complete MRD response (95 percent CI: 29.5 months - NE) versus 10.6 months (95 percent CI: 2.7 - 39.7 months) for those who did not achieve complete MRD response (n=13; p=0.008).

"The presence of MRD is a strong predictor of relapse in patients with B-cell precursor ALL," said Nicola Gökbuget, M.D., principal investigator for the BLAST study and head of the German Multicenter Study Group for Adult ALL in Frankfurt, Germany . "Results from the final follow-up of the BLAST trial at five years demonstrate that early achievement of complete molecular remission with Blincyto is associated with prolonged survival."Safety results among MRD-positive patients were consistent with the known safety profile of Blincyto.

MRD refers to the presence of cancer cells that remain detectable, despite a patient having achieved complete remission by conventional assessment. The presence of MRD is broadly considered the most important independent prognostic factor in ALL. MRD is only measurable through the use of highly sensitive testing methods that detect cancer cells in the bone marrow with a sensitivity of at least one cancer cell in 10,000 cells - versus about one in 20 with a conventional microscope-based evaluation.