. Selective GC receptor agonists and modulators and GC plus hydroxysteroid dehydrogenase inhibitor combination therapy are some of the approaches under consideration.
“There is growing observational data that confirms the GC-sparing effect seen in some of these clinical trials in real-world data,” said Sebastian E. Sattui, MD, assistant professor of medicine and director of the Vasculitis Center at the University of Pittsburgh Medical Center, Pittsburgh.
GC minimization is an important goal, “and the data emerging from these trials should be reassuring for rheumatology providers,” Dr. Sattui said.
Dr. Sebastian E. Sattui
HSD-1 Inhibitors Under Study
11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is a tissue-specific intracellular modulator of GC action that’s been trialed for a number of rheumatic conditions. “HSD-1 deficiency or inhibition has been consistently associated with reduced GC side effects in mouse and human,” wrote the authors of a study testing the coadministration of HSD-1 inhibitor SPI-62 (clofutriben) with prednisolone in patients with polymyalgia rheumatica (PMR) to measure its impact on efficacy and toxicity.
Lead study author David Katz, PhD, chief scientific officer at Sparrow Pharmaceuticals, presented results at the at the annual European Congress of Rheumatology.
GCs are often the first-line therapy with PMR. However, it’s very difficult for patients to stop taking GCs once they start taking them. The study included patients with PMR who were taking 10 mg/d prednisolone and didn’t require a dose increase. For the study, they continued prednisolone without dose reduction for 4 weeks, receiving either SPI-62 6 mg/d or a matching placebo for 2 weeks.
During SPI-62 treatment, researchers in sequential cohorts maintained daily prednisolone doses at 10 mg, adjusted to 15 mg or adjusted to 20 mg.
A 10-mg dose of prednisolone combined with 6 mg of SPI-62 demonstrated less efficacy compared with placebo but improved upon prednisolone toxicities such as bone formation and resorption biomarkers, lipidemia, and insulin resistance. Doubling the dose to 20 mg prednisolone combined with SPI-62 achieved similar efficacy and maintained improvement of prednisolone toxicity markers.
“In patients with PMR, when we double the dose of prednisolone during coadministration with a potent HSD-1 inhibitor, we are able to have similar stability of symptoms, physical function, and systemic inflammation. At the same time, we are able to show improvements on biomarkers of bone turnover and insulin resistance,” Dr. Katz informed the EULAR 2024 audience.
An ongoing phase 2 clinical trial is testing SPI-62 in patients with endogenous Cushing syndrome. “It’s a longer-term trial, so we’re able to see at least an individual patient’s more clinical outcomes such as reversal of Cushing’s-associated myopathy and the ability of patients to discontinue all of their antidiabetic medications and yet still have good glycemic control,” he said.
Another research team from the United Kingdom explored whether AZD4017, an inhibitor of human 11ß-HSD1, could mitigate GC effects. The researchers randomly assigned 32 healthy male volunteers to AZD4017 or placebo, along with prednisolone. They reported a worsening of hepatic insulin sensitivity in the placebo group but not in the AZD4017 group, and protective effects of AZD4017 on markers of lipid metabolism and bone turnover, as well as lowered nighttime blood pressure. The results signified that coadministration of AZD4017 with prednisolone in men could be a way to reduce GC side effects.
In a Japanese phase 1/2 study, 11ß-HSD1 inhibitor S-707106 proved useful as an insulin sensitizer and antisarcopenic and anti-obesity medication in 16 patients with Cushing syndrome and autonomous cortisol secretion.