VIENNA — With the glucagon-like peptide (GLP) 1 receptor agonist semaglutide (Wegovy) recently shown to significantly induce weight loss in people with osteoarthritis (OA) and obesity in the STEP-9 trial, could drugs traditionally used to treat type 2 diabetes be the next big thing for OA management?
"Hormone-based weight loss drugs are a game changer" for obesity management, Sébastien Czernichow, MD, PhD, said during a plenary session at the World Congress on Osteoarthritis (OARSI) 2024 Annual Meeting.
Drugs such as semaglutide may also have a cardioprotective effect, reducing the risk for major adverse cardiovascular events by as much as 20% vs placebo, added Czernichow, who is professor of nutrition at Paris Cité University and head of the Department of Nutrition at the George Pompidou European Hospital in Paris, France.
"You have to keep in mind that the short-term side effects are mainly gastrointestinal and [are] manageable. The mid-term side effects are an increased gallbladder [disease] risk, and the long-term benefits and risks are not really well known yet," Czernichow said. With regard to that, the effects of these drugs on lean body mass, bone health, and nutritional deficiencies need to be further evaluated and monitored.
Weight Loss Benefits
Weight loss is one of the cornerstones of OA management, and in addition to the weight loss seen with the GLP-1 receptor agonists, there have also been changes in body composition, Czernichow said.
In SURMOUNT-1, for example, the dual glucose-dependent insulinotropic polypeptide and GLP-1 receptor agonist tirzepatide (Zepbound) was shown to significantly reduce total fat mass with a smaller decrease in total lean mass in a subanalysis.
It has been argued that effects on body composition need to be considered when evaluating new weight loss drugs, and that focusing only on the degree of weight reduction is "encouraging inaccurate measures of medication efficacy for both patients and clinicians," Czernichow said, citing from a viewpoint published in JAMA Internal Medicine.
"The real question is: Are we able to fund these drugs for everyone? Or will only the richest patients be allocated to these drugs?" Czernichow said.
Weight Rebound
Tonia Vincent, MBBS, PhD, professor of musculoskeletal biology and an honorary rheumatologist at The Kennedy Institute of Rheumatology at University of Oxford in Oxford, England, was concerned about rebound weight gain.
"We hear a lot about this, that people stopping drugs actually get worse weight gain than before they started, and that's a concern about a drug that is going to have a huge pressure for supply," Vincent said following Czernichow's presentation.
Another delegate said that calling GLP-1 receptor agonists a "game changer" for weight loss in OA was premature because long-term results are needed.
"You mentioned that the double-digit weight loss is getting very close to the results from bariatric surgery, but bariatric surgery you do once, and for these drugs, to maintain the weight loss, you need to take them continuously," she said.
Weight Loss Affects Bone
Yet another delegate cautioned on the potential effects of significant weight loss on bone and cartilage. There is evidence, he said, that weight loss of 5-10 kg can significantly affect bone turnover, increasing bone resorption and thus putting patients at a risk of becoming osteopenic. "Are we looking at a new population of osteoporosis patients who may then also be at risk for fractures?" he asked.
Separately at OARSI 2024, Anne C. Bay-Jensen, PhD, chief technology officer at Nordic Bioscience in Herlev, Denmark, and colleagues reported data showing that weight loss was associated with an increase in bone and cartilage degradation.
Although Bay-Jensen and colleagues found that losing weight was associated with improved patient outcomes, there was a 1.58-fold increase in the bone resorption marker CTX-I in people who had lost weight vs a 1.37-fold gain in those whose weight remained stable and 1.11-fold increase in those who gained weight.
Moreover, there was a 1.15-fold increase in the cartilage degradation marker C2M in the weight loss group and 0.84-fold decrease in the interstitial matrix degradation marker C3M.
GLP-1 and Bone Effects
Another question is whether GLP-1 receptor agonists might be having direct effects on the bone that may be beneficial in OA. Research presented by postdoctoral researcher Eda Çiftci, PhD, of the AO Research Institute Davos in Davos, Switzerland, and collaborators during the poster sessions at OARSI 2024 suggest that they might.
Çiftci and researchers reported the findings of an in vitro study that looked at whether liraglutide might have anti-inflammatory and anabolic effects on a human chondrocytes model that had been treated with interleukin (IL)-1-beta to "mimic an inflammatory OA condition."
The release of the proinflammatory cytokines IL-6 and IL-8 was reduced by treatment with liraglutide when compared with control chondrocytes. Furthermore, the expression of the proteoglycan aggrecan — important for articular cartilage function — was also preserved.
These results suggest that liraglutide does indeed have anabolic and anti-inflammatory effects, Çiftci and fellow researchers concluded.
New Role for Dipeptidyl Transferase Inhibitors?
Researchers are also looking at the potential role for other diabetes medications in OA management, including the dipeptidyl peptidase (DPP) 4 inhibitors.
Although these drugs are considered "weight neutral," in vitro studies have suggested that the DPP4 enzyme may have a role to play in chondrocyte survival and inflammation, Yu-Hsiu Chen, of the Tri-Service General Hospital and the National Defense Medical Center in Taipei, Taiwan, told Medscape Medical News. The DPP4 enzyme inactivates GLP-1, so there is rationale there.
"Last year, we published a paper where we found the concentration of DPP4 in the synovial fluid was correlated with radiographic change in knee OA," Chen said. This time, "we're trying to see if a DPP4 inhibitor can be used as a treatment."
For their analysis, they used data on people newly diagnosed with type 2 diabetes who were and were not using DPP4 inhibitors obtained from Taiwan's National Health Insurance Research Database. This database contains information on 99% of the Taiwanese population, Chen said.
Matching 165,333 DPP4 inhibitor users with an equal number of nonusers showed that there was a significant 58% risk reduction for developing OA with DPP4 inhibitor use (hazard ratio, 0.42; 95% CI, 0.41-0.44).
DPP4 inhibitor use was also associated with a 58% risk lower risk for total knee replacement (TKR) and a 62% lower risk for total hip replacement.
Chen and colleagues concluded: "These results strongly indicate that DPP4 inhibitors could be considered as a viable treatment approach for individuals with type 2 [diabetes mellitus] who are at risk for developing OA or [who] already have OA."
Could Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors Be Beneficial?
So, what about SGLT2 inhibitors? Do they also have a potential role to play in managing people with OA, regardless of whether there is diabetes present? Perhaps, and their effect may be even greater than what's been observed for GLP-1 receptor agonists, as data presented by epidemiologist S. Reza Jafarzadeh, DVM, PhD, suggested.
"While GLP-1 receptor agonist drugs have been reported to reduce OA risk, largely attributed to their weight loss effect, SGLT2 inhibitors may provide a greater protective effect on OA outcomes," said Jafarzadeh, who is an assistant professor at Boston University in Boston.
He presented data from a large analysis of new users of SGLT2 inhibitors and GLP-1 receptor agonists within two claims databases — Merative (n = 603,471) and TriNetX (n = 1,202,972) — showing that SGLT2 inhibitors were associated with significantly lower risks for OA and the need for TKR.
Comparing new users of SGLT2 inhibitors and GLP-1 receptor agonists in the Merative dataset, the relative risks and odds ratios for OA were a respective 0.96 and 0.80, and having a TKR, 0.88 and 0.76.
Similar results were seen using the TriNetX dataset, with respective relative risks and hazard ratios of 0.90 and 0.85 for OA, and 0.81 and 0.78 for TKR.
In an interview, Jafarzadeh told Medscape Medical Newsthat the initial hypothesis was that because SGLT2 inhibitors have only a modest effect on weight loss, there would be no effect on OA outcomes.
"But we were surprised that it actually looked like they reduced the risk of OA outcomes even more than GLP-1 receptor agonists," Jafarzadeh said.
Further work is needed to understand these data, but they could mean that SLGT2 inhibitors, like GLP-1 receptor agonists, may have a role to play outside their current use in type 2 diabetes.
Czernichow disclosed ties with multiple companies, including BariaTek Medical, Boehringer Ingelheim, Bristol Myers Squibb, Fresenius, Janssen, Jellynov, Lilly, Novo Nordisk, Novartis, and ViiV Healthcare. Vincent had no relevant disclosures. Bay-Jensen is the chief technology officer and director of immunoscience at Nordic Bioscience. The work on the poster she presented at OARSI 2024 was funded by Nordic Bioscience. The work presented by Çiftci and colleagues was funded by the Eurostars-2 joint program with co-funding from the European Horizon 2020 research and innovation program. Çiftci had no personal disclosures to report. Chen's work was supported by the government of Taiwan, and she had no financial conflict of interest to disclose.Jafarzadeh had no conflicts of interest to disclose.
Sara Freeman is a freelance medical journalist based in London, England.
