Moxetumomab Pasudotox-tdfk Receives FDA Approval for Hairy Cell Leukemia Treatment

Hairy cell leukemia (hairy cell leukemia) treatment now has moxetumomab pasudotox-tdfk ( brand name Lumoxiti ), a new drug that, on 13 September 2018, received FDA approval.

Looking at the approval details, moxetumomab pasudotox-tdfk (Lumoxiti) injection received FDA approval for intravenous use in adults with relapsed (recurrent) or refractory (treatment-resistant) hairy cell leukemia who had received at least 2 previous lines of systemic treatment, including a purine nucleoside analog.

What is moxetumomab pasudotox-tdfk and how does it work?

Moxetumomab pasudotox-tdfk, immune system B cells carry a surface molecule called CD22, which this cytotoxin targets; it is the first treatment of its kind approved for hairy cell leukemia patients. CD22 is a regulatory molecule that prevents excessive immune activation and the development of autoimmune diseases. Moxetumomab pasudotox-tdfk is therefore an anti-CD22 immunotoxinin its action.

What is hairy cell leukemia?

Hairy cell leukemia rare cancersis one of these. Leukemiaof this type features B cells that, in a bone marrow sample under the microscope, appear hairy in appearance; it is a rare, slow-growing cancer. As the number of leukemic B cells increases, fewer healthy white blood cells, red blood cells and platelets are produced; this can lead to leukemia symptoms such as infection, anemia and bleeding.

What are the symptoms of hairy cell leukemia?

Patients with hairy cell leukemia usually seek medical attention for complaints such as low blood counts and splenomegaly (enlarged spleen). Although hairy cells are abnormal B lymphocytes, they generally do not cause lymph node enlargement. Hairy cells then begin to accumulate in the bone marrow, liver and spleen (probably because they multiply better in these organs).

Therefore, spleen enlargement and unexpectedly low blood counts are two important findings pointing toward a hairy cell leukemia diagnosis.

Hairy cell leukemia standard treatment: what is it?

It is generally an indolent (slow-progressing) hematological cancer. However, if it becomes symptomatic (causes complaints), pentostatin, cladribine and interferon-alpha significantly improve the disease prognosis (course) and also appear effective in relapse (recurrence). Patients with splenomegaly (enlarged spleen) causing severely low blood counts may undergo splenectomy (spleen removal surgery). After any of these standard treatments is started, the 5-year survival probability exceeds %85.

Recently, rituximab (an anti-CD20 monoclonal antibody), anti-CD25 (LMB-2) and anti-CD22 (moxetumomab pasudotox-tdfk) have increased the number of treatment options for hairy cell leukemia.

The study leading to FDA approval of moxetumomab pasudotox-tdfk

The effectiveness of moxetumomab pasudotox-tdfk was demonstrated in a phase III, single-arm, open-label trial involving 80 hairy cell leukemia patients who had received at least two lines of systemic treatment, including a purine nucleoside analog, a clinical trialthat provided this evidence. The study assessed sustained hematological remission (absence of any disease findings) 180 days after a complete response had been achieved, defined as a durable complete response as its measure. The study found that % 30 of patients achieved a durable complete response, and the overall response rate was % 75.

Common adverse effects of moxetumomab pasudotox-tdfk include administration-related allergic reactions, edema, nausea, fatigue, headache, fever, constipation, anemia and diarrhea among others.

The recommended moxetumomab pasudotox-tdfk doseis administered for up to 6 cycles or until disease progression or unacceptable toxicity (adverse effects), every 28 days, on days 1, 3 and 5 as a 30-minute intravenous infusion, at 0.04 mg per kilogramas the dosage.

Moxetumomab pasudotox-tdfk prescribing information warns healthcare professionals and patients about the risk of developing capillary leak syndrome . This condition causes fluid and proteins to leak into the tissues surrounding small blood vessels. Symptoms of capillary leak syndrome include difficulty breathing; weight gain; hypotension (low blood pressure); or swelling of the arms, legs and/or face.

The warnings also include the risk of hemolytic uremic syndrome, a condition caused by abnormal destruction of red blood cells. Patients should be aware of the importance of adequate fluid intake, and their blood counts should be monitored frequently. Other serious warnings include decreased kidney function, infusion-related reactions and electrolyte abnormalities. Moxetumomab pasudotox-tdfk should not be given to breastfeeding women.

In conclusion, moxetumomab pasudotox-tdfk, an anti-CD22 immunotoxin, represents a new treatment option for hairy cell leukemia patients whose disease progresses after trying other treatments.