Ibrutinib for Leukamia TreatmentLeukemia or blood cancer is of different types. Conventional treatment including chemotherapy, radiotherapy and intracethal chemotherapy wherein the drugs are directly injected into the spinal canal has mixed results, with some people responding and some even going into remission, while in some the disease progresses. Stem cell transplants are sometimes given to patients from donors and the aim of these treatments is to stop the disease progression, kill the cancerous cell or as a maintenance therapy. Now a new oral drug and a new therapy that is more targeted are undergoing clinical trials and the results are pretty good.

Oral drug for Chronic Cell Leukamia (CLL) and Mantle Cell Leukemia (MCL)

Janssen Biotech, Inc. and Pharmacyclics collaborated on an oral drug, Ibrutinib and have already received breakthrough therapy status for the drug for use in both CLL and MCL.

A research study by researchers co-led by Dr. Kristie Blum in Ohio State University’s Wexner Medical Center followed 85 patients of chronic lymphoctyic leukemia (CLL). The patients were given Ibrutinib. After two years and two months, the 83 percent of the patients were still alive, which is heartening news considering the disease is virtually incurable and results in early death. Usually the survival rates after diagnosis are a mere six to nine months, so 24 months is a big leap.

Ibrutinib is an investigational inhibitor of Bruton’s tyrosine kinase (BTK). This molecule is responsible for B-cell activation that is in turn responsible for many cancers that target the immune system including CLL and mantle cell lymphoma (MCL) and helps the tumors to grow. The drug binds with BTK and prevents the tumors from getting nutrients that help them grow. It works very differently from chemotherapy that destroys good and bad cells equally, so as the patient’s immune system is not compromised, he is in a better condition to fight the disease. If the BTK production is inhibited with the use of this drug, the incidence of cancer will reduce. Ibrutinib is thus one of the newer targeted therapies for cancer.

In fact the research showed that even those who received the drug and had been suffering from aggressive cancer that was marked by genetic mutations and were expected to die within two years, as well as some patients who did not respond to other therapies, had a positive response to this treatment. As much as 71 percent showed slowed tumor growth after two years and 75 percent showed that their cancers had not progressed much further after 26 months.

Another trial authored by Michael Wang, M.D., Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center also showed positive results. This trial was conducted on 111 patients of mantle cell lymphoma patients. They had relapsed or refractory disease and after taking the drug, 68 percent exhibited positive results. Of these patients 48 had earlier been treated by two cycles of bortezomib. Two doses were given – 51 patients were given 420 mg. a day, while 34 received 840 mg. a day.

Side effects were usually minor and the medicine was well-tolerated. Side effects included diarrhea, fatigue, upper respiratory tract infection, nausea and rash. Some people experienced anemia and/or low white blood cells. Trials are still on-going and it will take time for the drug to be available for general use as the drug is undergoing 30 different clinical trials. However, it has already received breakthrough therapy status from the FDA and it may actually be available later this year for general use.

Mantle cell lymphoma is particularly aggressive; unfortunately while patients usually have a positive response to high dose chemotherapy, they suffer from relapses and the cancer rapidly metastasizes. After Ibrutinib given in 28 day cycles of 560 mg of the drug daily, 68 percent of the patients responded to the treatment, of which 47 percent responses partially and 21 percent fully. In the end, the patients who responded had no disease progression for 14 months.

Apart from these two leukamias, even patients with Waldenstrom’s macroglobulinemia have shown positive results to this oral treatment.
Currently Pharmacyclics has 30 different on-going clinical trial on Ibrutinib and hopes that it will be able to file for a marketing patent later this year.

If Ibrutinib is combined with other therapies or drugs, the response may be even better and it may emerge as the first line of treatment for aggressive leukamias.

Another cancer breakthrough

A research team at Memorial Sloan-Kettering led by Renier Brentjens and Michel Sadelain may be on the verge of a breakthrough to treat B cell acute lymphoblastic leukemia or B-ALL. They genetically modified the patients’ own T-cells so that they would recognize and kill the leukemia cells.

While this treatment is experimental in nature in that only five patients have been treated. The four survivors (one died after a relapse) have been in remission for 5-24 months. In one patient, the cancer disappeared in eight days. They have all undergone bone marrow transplants as well after this treatment, which may have something to do with their survival rates. The study is ongoing.

When more patients undergo this therapy, more and clearer answers will emerge as to the efficacy of this therapy and whether it can be used as a standalone therapy or needs to be combined with other cancer treatments.

With an estimated 15,680 cases of CLL in 2013, there are so many families that will be affected by this disease. CLL affects older adults, predominantly male and there is always hope for cancer patients that they can beat the odds. MCL estimates are 69,740 new cases this year, an even larger number. B-All estimates are only 6,070, but this cancer has very short survival rates after diagnosis. Statistics never tell the full story because unless numbers are huge, they don’t seem scary. But the human stories are heart rending as the impact of a family member suffering from leukemia affect the whole family.

Sources:
American Cancer Society
National Cancer Institute
PubMed
New York Times