There has been much written about the rather minor improvement in breast cancer outcomes with Avastin (bevacizumab). My last post pointed out one theoretical problem with use of this drug in cancer.
The addition of bevacizumab to neoadjuvant chemotherapy significantly increased the rate of pathological complete response among patients with HER2-negative early-stage breast cancer. Efficacy was restricted primarily to patients with triple-negative tumors, in whom the pathological complete response is considered to be a reliable predictor of long-term outcome.
In the study 1948 newly diagnosed breast cancer patients were randomized to receive chemotherapy alone or with concomitant bevacizumab before surgery (neoadjuvant treatment). The results showed that pathological complete response was 18.4% in patients receiving bevacizumab and 14.9% without it. A difference of 3.5%, hardly significant. In patients with triple negative tumors (ER, PR and HER2 negative) the results were more impressive with 27.9% pathologic complete remission without bevacizumab and 39.3% with it. There was no difference in the 1262 ER PR positive patients. (7.8 and 7.7%)
We don’t know at this time whether the improved CR rate in these patients will translate into improved survival and hopefully cures.
Medicynical Note: What we can determine however is the cost of the intervention. Consider the 663 patients that were triple negative. I assume that about half (I don’t have full access to the article), let’s say 330 patients received bevacizumab. Then lets take the 39.3% complete response rate,11.6% more than those not receiving the drug, and do a rough estimate of cost.
39.3% of 330 is 129.69 patients achieved complete remission. 11.6% or 38.38 patients was the incremental benefit. Assuming a cost in the range of $50,000 for a 3-5 month course of treatment, the total cost of treating these 330 patients with the best outcome in the study would be (paying market prices for the drug) in the range of 16 and a half million dollars. Dividing that by the incremental benefit of 38.38 the cost of the benefit/patient was $429,911.
Cost is a real problem for a health care non-system that spends 17% of GDP on health care, almost twice that of other countries. Can we afford an intervention that costs over $400,000/patient who benefits?
I have no particular bias against Avastin (bevacizumab) except for the fact that it (and other similar drugs) appears to have very limited efficacy and is so expensive. If it were a drug costing $5000-10,000 for a course of treatment I’d say give it a try. At the present cost and level of efficacy it’s hard to find a strong argument for it’s use, except that it must make the manufacturers and their stockholder a great deal of profit.