Amgen (AMGN) reported on December 3, 2014 that the FDA has approved their Leukemia drug Blincyto (blinatumomab) for the treatment of Philadelphia Chromosome-negative Relapsed or Refractory B-cell precursor Acute Lymphoblastic Leukemia. This disease is an uncommon form of blood cancer where patients had few or no treatment options. With the approval of Blincyto patients now have the first single-agent immunotherapy to treat this rare blood cancer. This early approval comes as a surprise because Blincyto was not expected to receive approval until mid-May 2015; however, it was designated for priority review in October and also qualifies as an orphan drug and breakthrough therapy, hence the fast track.
Amgen's drug uses and directs the body's T-cells to target CD19 cells which are found on all B-cells. The targeting of these CD19 cells using Blincyto allows patients to go into complete remissions of their blood cancer — that is to clear the cancer from the body after treatment. Drugs that are built as immunotherapy drugs are becoming more prevalent in treating cancers because of the reduced toxicity associated with these types of treatments. The approval by the FDA was based on the fact that of the 185 patients recruited in the phase 2 trial 34.4% of them had complete remission of their blood cancer.
The breakthrough therapy designation was given because Philadelphia Chromosome-negative Leukemia is a serious condition with an unmet medical need as there are no other drugs approved. Priority review allowed quicker access to members of the FDA and allowed early approval of Blincyto. There is one condition to an Accelerated Approval, which is that the company must prove that the overall long term survival of the drug works; otherwise the FDA may revoke the approval status. Continued approval for this indication may be contingent upon verification of clinical benefit in subsequent trials.
