Novel, oral RGRN-305 shows promise in hidradenitis suppurativa treatment

Key takeaways:

• RGRN-305 is a heat shock protein 90 inhibitor, a molecular chaperone that causes inflammation.
• More patients treated with RGRN-305 achieved 50% disease clearance vs. placebo (50% vs. 20%).

RGRN-305 inhibits heat shock protein 90, and this action may modulate inflammation from hidradenitis suppurativa, according to a study.

Heat shock protein 90 (HSP90) is a molecular chaperone that promotes the activity of proinflammatory proteins, and since oral RGRN-305 inhibits HSP90, and the study authors believe it may be an effective therapeutic for inflammatory disorders, such as hidradenitis suppurativa (HS).

To investigate the efficacy and safety of RGRN-305 in HS, Hakim Ben Abdallah, MD, of the department of dermatology and venereology at Aarhus University Hospital in Denmark, and colleagues conducted a double-blind, proof-of-concept, placebo-controlled study. Ten patients were assigned to a once-daily 250 mg RGRN-305 tablet and five were assigned placebo for 16 weeks.

By week 16, six patients in the RGRN-305 group achieved the primary endpoint of a Hidradenitis Suppurativa Clinical Response 50 (HiSCR) compared with one patient in the placebo group.

Further, five patients and three patients of the RGRN-305 group achieved HiSCR75 and HiSCR90, respectively, whereas none of the placebo-treated patients achieved the same.

After 16 weeks, the mean improvement in HS-Physician Global Assessment was –0.8, with one patient in the RGRN-305 group achieving a clear or minimal disease severity score compared with no patients in the placebo group.

The authors reported that RGRN-305 was well tolerated with no deaths or serious adverse events. Placebo and RGRN-305 groups exhibited similar rates of treatment-emergent adverse events.

“The findings of this randomized clinical trial suggest that HSP90 inhibition by RGRN-305 may be a novel mechanism of action and a novel drug for treating hidradenitis suppurativa,” Ben Abdallah and colleagues wrote, “providing good short-term safety and the potential to reduce the disease activity.”