Treatment for Hematological cancers
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Treatment for Hematological cancers


Zytux is a biosimilar product with the generic name of  Rituximab and is used for treatment of some types of cancer. It is a chimeric monoclonal antibody against CD20 antigens presents on surface of lymphocyte cells.

Zytux is a genetically engineered human-mouse chimeric monoclonal antibody produced by Chinese Hamster Ovary (CHO) cells in suspension and purified by some steps of chromatography. It is a fusion of the light and heavy chain variable domains of a murine monoclonal anti-CD20 antibody and human kappa light-chain and gamma 1 heavy-chain constant regions. Active ingredient of Zytux, Rituximab, consists of two heavy chains of 451 amino acids and two light chains of 213 amino acids, with an approximate molecular weight of 148 kDa. Rituximab binds to the target CD20 antigen via the variable murine regions, while the remainder of the antibody interacts with human immune-effector mechanisms to kill the target cells.

Recommended International Nonproprietary Name (INN)


Chemical Abstracts Service (CAS) registry number.


Anatomical Therapeutic Chemical (ATC) code:



Mechanism of action

Rituximab is a monoclonal chimeric (mouse/human) antibody which binds specifically to the transmembrane antigen CD20 located on pre-B and mature B lymphocytes, but not on hematopoietic stem cells, pro-B cells, normal plasma cells or other normal tissue. The antigen is expressed on >95% of all B cell non-Hodgkin’s lymphomas. After antibody binding, CD20 does not internalize, nor is it shed from the cell membrane.CD20 does not circulate in plasma as free antigen and thus does not compete  for antibody binding. Studies  to date have found no connection between the intensity of CD20 expression on the malignant cells and treatment response.

Rituximab binds to the CD20 antigen on  B lymphocytes and causes B cell lysis. Possible mechanisms of cell lysis are complement-dependent cytotoxicity (CDC) together with antibody-dependent cellular cytotoxicity (ADCC) and induction of apoptosis.

Peripheral B cell counts fell below normal after the first dose of Zytux. In patients treated for hematological malignancy, B cells began to regenerate within 6 months of completing therapy, with values  reverting to normal within 9 to 12 months of completing therapy. Rituximab   sensitizes drug-resistant human B cell lymphoma lines to the cytotoxic effect of some chemotherapy agents.

Non-Hodgkin’s lymphoma

  • Treatment of patients with CD20-positive follicular non-Hodgkin’s lymphoma (stage III –IV) who have relapsed after, or failed to respond to, chemotherapy.
  • Treatment of previously untreated   patients with CD20-positive  follicular non-Hodgkin’s lymphoma (stage III –IV) in combination with standard CVP chemotherapy (8 cycles of cyclophosphamide, vincristine and prednisone).


  • Treatment of patients with CD20-positive   diffuse large B cell non-Hodgkin’s lymphoma (DLBCL)  in combination with standard CHOP (8 cycles of cyclophosphamide , doxorubicin , vincristine and prednisone).
  • Maintenance therapy of patients with relapsed or refractory CD20-positive follicular non-Hodgkin’s lymphoma (stage III –IV) who have responded to induction therapy with CHOP (6 cycles of cyclophosphamide ,doxorubicin ,vincristine and prednisone) or R-CHOP(6 cycles of CHOP plus Zytux)

Chronic Lymphocytic Leukemia (CLL)

Zytux is indicated for the treatment of patients with previously untreated or previously treated B-cell chronic lymphocytic leukemia (Binet Stage B or C) in combination with fludarabine and cyclophosphamide.

The use of Zytux in CLL patients is based on an improvement in progression-free survival.


Zytux is supplied as a sterile, clear, colorless, preservative-free liquid concentrate for intravenous (IV) infusion. It is provided in two dosages, 100 mg and 500 mg vials.

Active substance: rituximab

Excipients: sodium citrate, polysorbate 80, sodium chloride and water for injection.



Zytux 100: Each 10 ml vial contains 100 mg rituximab (rituximab conc. 10mg/ml)

Zytux 500: Each 50 ml vial contains 500 mg rituximab (rituximab conc. 10mg/ml)



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