NEW YORK (Reuters Health) - Biosimilar cancer drugs appear to be as safe and effective as the biologics they replace, and they cost much less, a systematic review and meta-analysis reports.
"We found that for three widely-used cancer biologic drugs - bevacizumab, trastuzumab, and rituximab - biosimilar drugs worked just as well as biologics in terms of their effectiveness," senior study author Dr. Aaron Kesselheim of Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, told Reuters Health by email.
Even though fewer than 2% of patients in the United States use biologic drugs, the authors write in The Lancet Oncology, biologics earned manufacturers $211 billion in revenue in 2019 and represented 43% of national drug sales.
Dr. Kesselheim and his colleagues searched standard medical databases for articles and abstracts in English published until April 2021. They included all publications that compared a disease-modifying cancer biologic with its biosimilar and reported efficacy or surrogate efficacy results.
The researchers found six reference drug trials involving 1,811 participants for the three brand-name cancer biologics included in the meta-analysis and 31 studies involving 12,310 patients for their biosimilars.
The investigators analyzed the study designs of biosimilar efficacy clinical trials and compared them with the designs of the reference drug pivotal trials. They considered population size, blinding, and randomization; and they collected risk ratio estimates for relative change to surrogate measures, such as progression-free survival.
Biosimilar studies included an average of 397 participants compared with 302 in reference drug trials. Biosimilar studies also were more likely to be randomized clinical trials than single-group or observational studies (31 of 31 vs. 3 of 6, respectively), and they were more likely to be double blind than open label (26 of 31 vs. 1 of 6).
On meta-analyses, biosimilars were found to have been subjected to rigorous clinical evaluation and to be as effective as their reference biologics across all drugs, cancer types, and outcomes.
"The U.S. Food and Drug Administration review process is rigorous, and generic drugs have long been safely used in the market," Dr. Kesselheim said. "But there is substantial skepticism among some physicians and patients about using biosimilars because biologic drugs are generally more complex than generics," he noted.
"We hope this study adds to the growing literature supporting the safety and effectiveness of biosimilar drugs so cancer patients can feel comfortable requesting these drugs and can benefit from their lower prices," he said. "It will be important to continue to follow the outcomes from biosimilars used in patients to see if any new issues emerge in routine clinical use."
Dr. Joseph Alvarnas, a professor in the Department of Hematology & Hematopoietic Cell Transplantation at City of Hope Comprehensive Cancer Center in Duarte, California, who wasn't involved with the study, welcomed the results.
"This robust meta-analysis validates that these are effective agents and that the clinical trials that have been performed as part of the evaluation and approval process for biosimilars are robust, effectively powered, high-quality studies," he said by email. "My hope is that these data help increase clinicians' willingness to consider the use of biosimilars in their patient care."
The FDA has approved 33 biosimilars, Dr. Alvarnas added. "Knowledge of biosimilars and their potential use will be a key component of moving toward greater care efficiency and therapeutic stewardship."
"Biosimilar price transparency is critical, and any cost savings should be passed on to patients," advised Dr. Douglas W. Blayney of Stanford University School of Medicine in Stanford, California, coauthor of an accompanying editorial.
"For safety, future meta-analyses should have a broader scope to capture negative or non-reported trials; and we should enhance pharmacovigilance monitoring to detect new and rare drug side effects," he said by email.
Arnold Ventures supported the study. The authors declare no conflicts of interest, and Dr. Blayney declares financial relationships with the pharmaceutical industry unrelated to the study.
SOURCE: https://bit.ly/3h177GB and https://bit.ly/3gHHxWK JAMA Oncology, online February 3, 2022.
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