Challenges of Cancer Biologics
They are made in living cells, so the specific expression system affects the nature of the resultant protein. Moving from one type of cell expression system, such as a mammalian Chinese hamster ovary (“CHO”) cell system to a bacterial Escheria coli cell system, will result in changes in the protein even if the gene sequence is the same, and this may alter its biologic function. As a result, there are no true “generic” versions of a biologic like there are with small molecules. Instead, recombinant proteins with the same gene sequence made in different expression systems are called “biosimilars.” The first cancer biosimilars have only recently been approved for clinical use in the U.S., although many are already on the market in Europe. Other variations of a specific biologic, where changes are made to improve function, are called “biobetters.” Biobetters are essentially novel drugs, even though they look similar to the protein they are based upon.
Cancer biologics require a sophisticated and expensive infrastructure to produce and deliver. Manufacturing facilities to make the large quantities of biologics can easily cost hundreds of millions of dollars and require hundreds of people. The resultant product must be maintained under proper refrigeration from manufacture to use in the patient. Many biologics must be delivered by intravenous infusion over a period of hours. This requires an infusion center with skilled staff and can run thousands of dollars per visit.
In the end, biologics therapy for cancer is an expensive proposition, with the prices of therapeutics often topping $100,000 per year. In many cases the benefits for overall survival may be modest. For example, the biologic Avastin (bevacizumab, Roche) is used to inhibit the growth of vasculature in tumors that enables cancer growth and progression. It is used together with chemotherapy regimens. In advanced colon cancer, bevacizumab therapy can run about $60,000 for a full line of treatment, but the use of the drug may only add one to three months to overall survival. With over 30,000 patients eligible for this treatment each year, this potentially represents nearly $2 billion in health care costs for relatively modest patient benefit. The high price of biologics therapy has contributed to the significant rise in the cost of cancer medicines, which in the U.S. have increased 88% over the last five years and now account for half of the cost of cancer care. This trend has continued with the release of the new immune checkpoint blockade therapies, many of which are priced at up to $150,000 for a course of therapy. This trend is not sustainable.