July 12 (UPI) -- Many newly approved cancer drugs fail to clearly communicate survival benefits associated with their use on the label, according to an analysis published Monday by JAMA Internal Medicine.
Of the 125 drugs designed to treat cancer approved by the U.S. Food and Drug Administration between 2014 and 2018, 22 included evidence on their effects on overall survival on their package insert -- the detailed information on effectiveness, safety and side effects provided -- the data showed.
Trials for less than half of the drugs approved by the agency during that period measured overall survival, or "how long patients live after treatment."
The measure "is arguably the most definitive patient-relevant outcome when evaluating cancer drugs," researchers said.
"Patients may be surprised to find out that regulatory agencies do not always evaluate the survival benefits of new cancer drugs," study co-author Huseyin Naci told UPI in an email.
"It is therefore difficult for prescribers, as well as for patients, to understand using the label whether a cancer drug prolongs survival in its approved indication," said Naci, an associate professor of health policy at the London School of Economics in England.
Many clinical trials for cancer drugs focus on "progression-free" survival, which refers to the length of time during and after treatment that a patient lives with the disease but it does not get worse, according to a study published in October.
However, this may mean that patients on these drugs are receiving toxic and expensive treatments while not necessarily extending their lives, the researchers on that study said.
Cancer drugs are some of the most expensive medications approved by the FDA, with prices more than doubling over the past decade, an analysis published earlier this month found.
For the new study, Naci and his colleagues reviewed the package inserts for the 125 cancer drugs approved by the FDA over a five-year period from 2014 through 2018.
Of the approved drugs in the study that reported overall survival data in their package inserts, 23 based the data on results from "interim analyses" of clinical trials -- analyses that were conducted before the data collection process has been completed.
Of 27 labels that reported data from final analyses of clinical trials, 12 "explicitly stated" statistically significant gains in overall survival gains following treatment.
In addition, two "explicitly stated" that treatment with the drugs did not provide a statistically significant benefit in overall survival.
Most of the remaining drugs offered "no explicit statement" on overall survival in their package inserts, with many requiring prescribers and patients to "infer" it "from numerical data presented in either tables or graphs," according to the researchers.
Interpreting these findings "often requires familiarity with advanced epidemiological and statistical concepts," the researchers said.
"We think FDA should standardize labeling with regard to overall survival," Naci said.