AstraZeneca Gains United States Approval for Lymphoma Drug
Some forms of lymphoma are rarer than others. Most people can recognize Hodgkin lymphoma, but mantle cell lymphoma will strike them as a surprise.
Because it is so rare, there are not as many drugs specific to this form of cancer. One has recently been approved in the United States, by the Food and Drug Administration. The drug is called Calquence, produced by AstraZeneca.
Mantle cell lymphoma
This form of cancer is known as a non-Hodgkin lymphoma. Only about six percent of non-Hodgkin lymphoma manifests itself in the form of mantle cell lymphoma. It is one of the rarer forms of cancer. Only about 4,200 people are diagnosed with the cancer each year, mostly people who are middle aged or elderly.
The current median survival after diagnosis is between five and seven years, because “mantle cell lymphoma is a particularly aggressive cancer,” according to Dr. Richard Pazdur. He is the director of the FDA’s Oncology Center of Excellence.
The cancer occupies the mantle zone of the germinal center of the lymph nodes. This is only a small part of the lymph node, but that does not make this cancer any less deadly than others.
Enlargement of the lymph nodes is the most telling symptom of this cancer. Other symptoms include weight loss, fever, excessive sweating at night, and enlargement of the spleen. The same type of mantle cells found around lymph nodes are also found in the spleen.
Existing treatments
Because mantle cell lymphoma is such a rare form of cancer, there are no standard protocols for treatment as there are for Hodgkin lymphoma. Relapse is unfortunately common to people who are treated for mantle cell lymphoma, and each time the relapse occurs faster and is harder to beat.
Chemotherapy is the de facto standard, on account of its ability to be useful against most forms of cancer. As most people well know, chemotherapy has large amounts of side effects, which is why other treatment options are being researched. Also, it is particularly ineffective after a relapse.
Stem cell therapy, immunotherapy, and the usage of targeted drugs are also part of the treatment for mantle cell lymphoma. The problem with all of these however is that research on their efficacy is scant. The best options are not yet known.
The new treatment, just approved, may be a good option to supplement or even replace these therapies. It may even become part of a new standard of treatment for mantle cell lymphoma.
AstraZeneca PLC’s new treatment, Calquence
This medication is also known as acalabrutinib. It is a Bruton’s tyrosine kinase inhibitor, which means that it prevents the enzyme known as Bruton’s tyrosine kinase (also called BTK) from acting out its duty.
BTK is naturally used in the human body as part of the creation process for B cells, also called B lymphocytes. They are a white blood cell created by the lymph nodes and used by the body to create antibodies, antigens, and cytokines.
The problem is that the very same enzyme that helps the body create its defenses is also part of the biomechanisms by which mantle cell lymphoma creates more and more cancerous cells.
Calquence strikes at this enzyme and prevents it from being utilized by the cancer cells to divide and reproduce. Calquence is not the first drug to have this sort of activity. Ibrutinib is also used for this purpose.
What Calquence does better than ibrutinib is that it is both more selective and more potent. In other words, it does not interfere with other, innocent, kinase enzymes. It also inhibits BTK to a greater effect than does ibrutinib.
So, it is stronger than existing drugs, while attacking less of the body. What does the research look like?
Research on Calquence
Though the FDA has approved Calquence as a treatment option, the drug is not yet out of the study phase. It has been tested on both dogs and human, and shows promise for both.
First, they tested dogs with this type of lymphoma. Dogs were chosen because they were one of the few animals which exhibited the same type of mantle cell lymphoma as humans.
The researchers found that the drug not only inhibited the growth of new cancer cells, but it also decreased the survival of existing cancer cells. This clinical benefit was seen in 30% of the dogs at the dose level chosen, higher than the average for similar drugs and similar cancers.
It was also found to be better tolerated by the dogs than other medications, which could potentially mean that higher doses would be acceptable. It was also conjectured that the effect was dependent on the size of the dose, so if they had used a higher dose more of the dogs would have seen a benefit.
This conjecture came about because some of the dogs were more sensitive to this type of medication on account of their medical history, and they were the ones which saw more of a benefit.
Some of the dogs, about 30%, did have a negative reaction to the medication. They typically exhibited symptoms relating to the gut, such as weight loss, vomiting, and diarrhea. Still, the side effects were better than other, similar drugs.
Now, onto the humans.
AstraZeneca sponsored a study of 124 patients with mantle cell lymphoma. All of them had received at least one form of cancer treatment before this study.
81% of the participants of the study saw a beneficial effect of the medication. 41% of the patients had their tumors shrink from the drug. The other 40% saw remission of their cancer!
Those are promising numbers, but should be taken with a grain of salt. First of all, the study was sponsored by the makers of Calquence, so there may have been a bias in the research. Secondly, there was no comparison group of patients who did not take the drug.
Though it is very likely that Calquence is why those participants saw such a positive effect, unless there is a control group, you cannot know without a shadow of a doubt that they would not have gone into remission anyway. Or perhaps some other part of their testing method was the cause of the shrinking tumors.
Also, some of the side effects are cause for caution. The drug, by its nature, heavily decreases the amount of a certain type of white blood cell. Some of the patients saw serious infection. Also, a couple of the participants developed a second type of cancer.
It may have been unrelated or may have been because of the drug, which is why more research is being performed on the medication. Chances are that the second cancer was unrelated to the drug itself and was just uncovered during the study, but it is always better to know for sure.
The cost of the drug
Here comes the bad news. If you do not have insurance, the cost of the drug is expected to be $14,260 every month. This covers two pills per day, so the cost is almost $240 per dose.
Though this seems like a steep price to pay to live, AstraZeneca has expressed that they desire to help the financially unable. They will offer patients financial assistance. That may include copayment cards of such a value that they will cover the out-of-pocket costs for some patients who need the drug.
Final thoughts
Mantle cell lymphoma is a rare type of cancer which effects a certain outer layer of lymph nodes as well as the spleen. There are not standard treatment protocols for this cancer, and most of the medications available have been heavy on side effects and not as efficient as desired.
AstraZeneca has recently developed a drug which may turn that trend around. It shows promise so far in trials, and has even been approved by the FDA as a treatment option. It is still in the experimental phases, but if you have mantle cell lymphoma, it may remove 6-year survival prognosis in favor of a complete remission.
References
https://www.dddmag.com/news/2017/11/astrazeneca-wins-us-approval-lymphoma-drug
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159607
