Cancer being a life-threatening condition with unmet medical need, many cancer drugs are approved through an accelerated approval pathway introduced by US FDA in 1992 based on surrogate endpoints. Studies have found that only a small % of FDA/EMA approved cancer drugs from 1992-2017 through accelerated drug approval showed any clinical benefit in post-marketing studies. The blog highlights the downsides of accelerated cancer drug approval.
The United States FDA initiated the Accelerated Drug Approval Program in 1992 so that there could be a faster and more streamlined process for new drugs (including cancer drugs) to come to market and meet the needs of serious unmet medical conditions. In theory, this program does make sense because drug companies will be incentivized to get their drugs approved faster through this program to start monetizing sooner, and the patients facing conditions with no successful drug in the market will be more than pleased to try out anything new. However, because pharma companies are not required to conduct the large and detailed clinical trials required of the routine drug approval process before introducing their drugs to market through this program, a large percentage of these drugs have been found not to show clinical benefit.
Use of Surrogate End Points in Accelerated Cancer Drug Approval
Essentially, in order to get their drugs temporarily approved and into the market through this accelerated approval program, drugs are evaluated by markers known as surrogate endpoints which are basically supposed to predict potential clinical benefit. A surrogate endpoint is a more easily measurable laboratory test finding (biomarker assay) or a physical sign that may not be a direct measure of how a patient feels, functions or survives, but it is still considered likely to predict therapeutic benefit for the patient. This method is much quicker than conducting a set of full fledged clinical trials because that would last several years in order to see the results on patient overall survival and quality of life impact, and gather conducive data. The surrogate endpoints accepted for drug approval in the accelerated trials include impact on some clinical biomarker that is a protein that is strongly associated with the disease, or tumor size reduction, reduction in blast cell counts for leukemias, or endpoints such as progression free survival (PFS) that is the number of days, weeks or months the disease has not progressed in the patient. The PFS endpoint does not necessarily correlate with patient overall survival or improvement in quality of life. Using surrogate endpoints for accelerated drug approvals in life-threatening diseases (like cancer) as quick tests for viable clinical success, is like testing out one tyre to predict the future safety of the cars.
A study done by the Harvard School of Medicine found that out of the 93 drug indications granted approval through the Accelerated Approval Program of the FDA from 1992 to 2017, ‘20% had improvement in overall survival, 21% had improvement in a different surrogate measure, and 20% had improvement in the same surrogate measures used in confirmatory trials and preapproval trials’ (Gyawali B et al, JAMA Intern Med. 2019). This means that of all the approved drugs, a very small number of drugs was actually able to show clinical success in the confirmatory trials. Confirmatory trials are essentially the post-marketing trials which pharma companies are mandated to conduct, to let the FDA decide whether to allow the drug to stay in the market or revoke it. However, the system is majorly flawed because a significant number of pharma companies just use the same pre-approval endpoint surrogates for their confirmatory trials instead of assessing true therapeutic benefits such as overall survival and quality of life impact.
Furthermore, most of the drug indications approval from the FDA are based on recommendations from different scientific groups such as NCCN, the National Comprehensive Cancer Network; ASCO, American Society for Clinical Oncology; ASH American Society for Hematology and others. These agencies set the treatment guidelines for the oncology community that is then covered by the payers including Medicare and private insurance companies. In a study done by researchers from the Oregon Health and Science University comparing the drugs approved by the FDA and recommended by NCCN, researchers found that “the NCCN frequently recommends beyond the FDA approved indications” and that the “strength of the evidence cited by the NCCN supporting such recommendations is weak” (Wagner J et al, BMJ. 2018).
The above highlights the nexus between the big pharmaceutical companies who are exploiting the accelerated approval pathways, the government agencies who charge a higher price for accessing these accelerated approval processes, and clinical groups and associations that are supported by the pharma, that are in turn promoting the use of overpriced and toxic drugs in patients without strong evidence of being effective in improving patient quality of life or overall survival. From the patient perspective, new and more expensive drugs may not always be the better options for treatment and we need to demand more studies on cost/benefit analysis of the expensive marketed treatments for cancer.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer. Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.