The National Cancer Institute recently revealed that acute lymphoblastic leukemia (ALL) is projected to affect around 5,970 individuals and could kill almost 1,440 people in the United States this 2017. Fortunately, a new drug known as Besponsa (inotuzumab ozogamicin) has been approved by the U.S. Food and Drug Administration (FDA) as the new treatment for relapsed or refractory B-cell precursor ALL among adults.

The FDA approval of the drug came after the approval from the European Union earlier this year. Since there are only a few treatments available for patients with B-cell precursor ALL, Dr.

Richard Pazdur, FDA’s Oncology Center of Excellence director and the agency’s Center for Drug Evaluation and Research’s Office of Hematology and Oncology Products acting director, said in the news release that the approval of the drug will provide a “new, targeted treatment option” to the patients.

B-cell precursor ALL

Considered a rare and rapidly progressing type of leukemia or blood cancer, the relapsed or refractory CD22-positive B-cell precursor ALL is a condition in which the bone marrow makes an excessive amount of B-cell lymphocytes, which are an immature type of white blood cells, Reuters noted.

If left untreated, the condition can be fatal within a matter of months. The current standard of care for patients with the condition is “intensive chemotherapy.”

The drug

The recently approved drug by the FDA called Besponsa is a product of the collaboration between Pfizer Inc., which bears the exclusive responsibility for all the drug’s manufacturing and clinical development activities, and Celltech (now UCB).

It is an “antibody-drug conjugate (ADC)” that is composed of a monoclonal antibody (mAb) targeting CD22.

CD22 is a “cell surface antigen” found on cancer cells in most B-cell ALL patients that are associated with a “cytotoxic agent.” According to Pfizer, Besponsa works by binding to the CD22 antigen on B-cells. When the drug is incorporated into the cell, it releases the cytotoxic agent called calicheamicin, which will be targeting the destruction of the cancer cell.

Side effects

Despite being an approved monotherapy for treating a rare type of leukemia among adults, patients are also warned of its side effects that include infection, anemia, hemorrhage, thrombocytopenia, neutropenia, leukopenia, pyrexia, febrile neutropenia, increased transaminases, increased gamma-glutamyltransferase, hyperbilirubinemia, fatigue, nausea, headache and abdominal pain. For more serious adverse reactions, the drug could cause veno-occlusive disease/sinusoidal obstruction syndrome.

Other serious side effects listed also include infusion-related reactions, blood cell and platelet production reduction (myelosuppression), and QT interval prolongation. Pregnant or breastfeeding women, however, are deferred to take the drug due to the impact or harmful effects it may cause to the developing fetus or the newborn baby.

Boxed warning

In addition to the side effects, the drug also carries a boxed warning from the FDA. In fact, patients who are treated with Besponsa are at risk of severe liver damage. Those patients who take the drug following a stem cell transplant, on the other hand, will be at high risk of death.


Meanwhile, Pfizer revealed that the total cost of the drug will be $168,300, as based on the usual duration of treatment and before buyers’ discounts. The pharmaceutical company added that the drug’s list price “is not necessarily what patients actually pay,” while “out-of-pocket” expenditures differ depending on the health care premium coverage of the patients and the treatment’s duration.