Use of Obesity Drugs in Cancer Patients Increases Despite Lack of Clinical Guidance

 

• Prescriptions for GLP-1 receptor agonists in cancer patients have increased despite lack of clinical guidance.
• The overall prescription rate was low (4.1%) but increased significantly over 4 years.
• The highest prescription rates occurred in obesity-related cancers -- thyroid, breast, and endometrial.

Prescriptions for GLP-1 receptor agonists for patients with cancer have increased despite a lack of clinical guidance on the drugs' safety and efficacy in cancer, a large retrospective review of health records showed.

Overall, 4.1% of nondiabetic patients with one of 14 different cancers had at least one prescription for semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) during a 4-year period ending May 2025. The annual prescription rate remained low at 0.7% at the end of the study period, but the rate increased significantly from 0.01% to 0.9%.

Prescription prevalence also increased during the study period and was highest among patients with three types of cancer associated with obesity -- thyroid, breast, and endometrial -- reported Yuan Lu, ScD, of Yale School of Medicine in New Haven, Connecticut, and colleagues in JAMA Oncology.

"We don't have any robust evidence of the benefit or harm of these drugs in cancer patients," Lu told MedPage Today. "We need future research to look into this issue."

"I know that many researchers are trying to look at real-world evidence, such as electronic health records [EHR], to identify what are the real-world efficacy and safety of these drugs," she added. "The primary reason for that is most of the important clinical trials exclude cancer patients, so we don't have any evidence from the trials. It's too expensive to conduct trials in cancer patients, and it probably takes too long to get the result."

EHR and claims data, combined with analytic methods, can mimic clinical trial design to examine the drugs' benefits and safety in patients with cancer.

"I think guideline committees probably are waiting for the evidence to come out, because there is not much, in terms of recommendations, in cancer guidelines for these drugs," said Yu. "If there is anything, it's just based on expert opinion. We need data to support that."

GLP-1 agonists have revolutionized treatment of obesity, but cancer-specific considerations of the drugs have received little attention to this point. The potential for complications, such as drug-drug interactions or cachexia, raise questions about the use of the drugs in patients with cancer, Yu and colleagues noted.

To investigate current prescribing practices for GLP-1 agonists in patients with cancer, the authors searched the Epic Cosmos Dataset for adults with new diagnoses of one of 14 types of cancer from January 2021 to May 2025: bladder, breast, colorectal, endometrial, kidney, leukemia, liver, lung, melanoma, non-Hodgkin's lymphoma, pancreatic, prostate, thyroid, and multiple myeloma. Eligible patients had a body mass index (BMI) ≥30 and at least one obesity-related comorbidity. Patients with type 2 diabetes were excluded.

The search identified 569,580 patients with a cancer diagnosis, 23,557 (4.1%) of whom had at least one prescription for semaglutide or tirzepatide during the study period. Patients with prescriptions were younger (58.7 vs 67.1, P<0.001), more likely female (70.6% vs 52.1%, P<0.001), and had a higher BMI (37.8 vs 33.3, P<0.001).

Although the overall prescription rate was low, the trend of increasing prescriptions increased significantly during the study period (0.01% to 0.9%, P<0.001). Prescription rates were highest among three obesity-related cancers: thyroid (10.1%), breast (7.2%), and endometrial (7.1%). The lowest rates were in patients with lung (2.8%), liver (2.4%) and pancreatic cancer (1.3%).

"The relatively high prescribing rate among patients with preexisting thyroid cancer is noteworthy," the authors noted. "Papillary thyroid cancer is an obesity-related and most common type of thyroid cancer. These medications are contraindicated for use in medullary thyroid cancer based on preclinical animal studies."

"Given the rapid and heterogeneous adoption of GLP-1 [receptor agonists] in populations with preexisting cancer but without diabetes -- and absence of cancer-specific prescribing guidelines -- there is an urgent need for evidence-based recommendations to optimize safety and outcomes," they added.

Disclosures

Lu disclosed relationships with Novartis and Sentara Research Foundation. Co-authors disclosed multiple relationships with governmental, non-profit, and commercial entities.

Primary Source

JAMA Oncology

Source Reference: Kim C, et al "Semaglutide and tirzepatide prescribing for obesity in patients with preexisting comorbid cancers" JAMA Oncol 2025; DOI: 10.1001/jamaoncol.2025.4560.

https://www.medpagetoday.com/hematologyoncology/othercancers/118366