Tuesday, February 23, 2021

Immunization and immunotherapy updates for family physicians

 - Kenny Lin, MD, MPH

The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) 2021 Adult and Child/Adolescent Immunization Schedules included a number of key updates that are discussed in the February 15 issue of AFP. The schedules included information on the two messenger RNA vaccines against SARS-CoV-2 that have received Emergency Use Authorization from the U.S. Food and Drug Administration (FDA): the Pfizer-BioNTech vaccine for persons older than 16 years and the Moderna vaccine for persons older than 18 years. As Dr. Jennifer Middleton noted in a previous blog post, additional vaccines with different mechanisms may become available in the U.S. soon; data on the Janssen adenovirus vector vaccine will be reviewed at a meeting of the FDA's Vaccines and Related Biological Products Advisory Committee later this week.

The ACIP recommends shared decision-making (SDM) for the 13-valent pneumococcal conjugate vaccine (PCV13) in adults older than 65 years, meningococcal B vaccination for adolescents and young adults aged 16–23 years, hepatitis B vaccination for adults older than 60 years with diabetes mellitus, and human papillomavirus vaccination for adults aged 27–45 years. According to its website, "Generally, ACIP makes shared clinical decision-making recommendations when individuals may benefit from vaccination, but broad vaccination of people in that group is unlikely to have population-level impacts." In a study published in the Journal of General Internal Medicine, researchers surveyed 617 primary care physicians recruited from the American College of Physicians and the American Academy of Family Physicians about their knowledge, attitudes, and experience with SDM vaccine recommendations. Most participants agreed that SDM requires more time than typical vaccine recommendations, is facilitated by specific talking points, can create confusion for patients, and may be difficult to implement. Compared to family physicians, general internists were more likely to report not knowing how to implement SDM recommendations as intended by the ACIP.

The February 1 issue of AFP included an article on targeted cancer therapies by Drs. Claire Smith and Vinayak Prasad. Targeted therapies may be monoclonal antibodies, small molecule inhibitors, antibody-drug conjugates, and/or immunotherapy. Immune checkpoint inhibitors (ICIs) - monoclonal antibodies that block inhibitory regulatory proteins and lead to T-cell activation - have a wide range of toxic effects on various organ systems, with thyroiditis being the most common. Family physicians should be aware of these potential adverse effects and their initial management in patients being treated with ICIs.

Finally, the AFP article mentioned the increasing financial toxicity of targeted cancer therapy:

In 2020, the average out-of-pocket cost to a patient for a course of oral cancer therapy was estimated at $5,663. According to one large analysis, 20% of patients with cancer take less medication than prescribed, 19% partially fill oral cancer therapy prescriptions, and 24% avoid filling a prescription at all. Many patients in this study reported spending less money on food, leisure, and clothing. Approximately 2% of patients will declare bankruptcy during their treatment; those with advanced disease are more likely to declare bankruptcy. Bankruptcy during cancer treatment increases the risk of death.

In a recent commentary in JAMA Internal Medicine, Dr. Prasad argued that the problem of unaffordability is compounded by the FDA's lenient approval process for new cancer drugs and subsequent mandatory Medicare coverage for approved drugs without price negotiation. Only a fraction of cancer drugs approved in the U.S. (often based on studies with surrogate end points rather than evidence of benefits in survival or quality of life) are approved for broad coverage in England and Canada. Not only is the clinical effectiveness of many of these drugs uncertain, but their value (cost-effectiveness) is questionable as well.