A recent study conducted by Swedish investigators suggests that the once-a-day injectable insulin medication marketed by Sanofi Diabetes under the name Lantus may be linked to cancer. The results of this study, presented at the San Antonio Breast Cancer Symposium on December 6, 2011, are of particular interest to those with diabetes, as this particular treatment may increase their chances of developing cancer.
In the study, researchers reviewed the medical records of over 23,000 Swedish patients. Although researchers were unable to pinpoint exactly which cancers patients taking Lanus were more likely to develop, they argued that the prescription medication made patients up to 2.9 times more likely to be diagnosed with cancer. In contrast, for those taking metformin, a generic form of insulin, the risk of cancer was actually reduced by about eight percent.
Lantus Previously Linked to Cancer, Though Results Ambiguous
This is not the first time Lantus has been in the spotlight for its potential link to increased cancer risks. For example, a 2009 study unveiled a correlation between Lantus use and an increased risk of developing tumors. However, it is important to note that at least two other studies have failed to show the same link. Moreover, a study presented on December 7, 2011 at Dubai’s World Diabetes Congress indicates that there is no link between Lantus and an increased risk in developing breast cancer or other cancerous tumors.
In a study presented earlier this year, U.S. researchers argued that there was no clear tie between Lantus and cancer. There also seems to be a link between diabetes and breast cancer, due to the fact that women diagnosed with diabetes are more likely to develop breast cancer during the four years following the diagnosis. This risk is present regardless of the treatment prescribed for managing the diabetes.
Reactions to the Recent Study
Paris-based Sanofi has already released a statement expressing concern over the recent study, arguing that the sample size was too small to draw definitive conclusions. Moreover, it is unclear whether the medical histories of both diabetics and nondiabetics were considered. If this is the case, it is possible that the results are skewed, because those with diabetes tend to be older individuals who may already be more likely to develop certain types of cancer. Further studies have already been conducted by Sanofi, with results expected later this month. This more robust sample of over one million patients includes diabetics from five different European countries.
Concerns regarding the possible link between taking Lantus to treat diabetes and an increased risk of developing cancer have not hindered sales. In fact, shares were up two percent, and overall the stock is up 10 percent from last year. Considering the reservations regarding the study sample and methodology, further results are needed before this issue can be resolved. In the meantime, diabetics have found positive results from taking Lantus to treat their conditions. In fact, Lantus is the best-selling treatment, selling twice as many units as competitors Levemir and Novo Nordisk.