Oral hymecromone decreases hyaluronan in human study participants

Abstract

BACKGROUNDHyaluronan (HA), an extracellular matrix glycosaminoglycan, has been implicated in the pathophysiology of COVID-19 infection, pulmonary hypertension, pulmonary fibrosis, and other diseases, but is not targeted by any approved drugs. We asked whether hymecromone (4-methylumbelliferone [4-MU]), an oral drug approved in Europe for biliary spasm treatment that also inhibits HA in vitro and in animal models, could be repurposed as an inhibitor of HA synthesis in humans.METHODSWe conducted an open-label, single-center, dose-response study of hymecromone in healthy adults. Subjects received hymecromone at 1200 (n = 8), 2400 (n = 9), or 3600 (n = 9) mg/d divided into 3 doses daily, administered orally for 4 days. We assessed safety and tolerability of hymecromone and analyzed HA, 4-MU, and 4-methylumbelliferyl glucuronide (4-MUG; the main metabolite of 4-MU) concentrations in sputum and serum.RESULTSHymecromone was well tolerated up to doses of 3600 mg/d. Both sputum and serum drug concentrations increased in a dose-dependent manner, indicating that higher doses lead to greater exposures. Across all dose arms combined, we observed a significant decrease in sputum HA from baseline after 4 days of treatment. We also observed a decrease in serum HA. Additionally, higher baseline sputum HA levels were associated with a greater decrease in sputum HA.CONCLUSIONAfter 4 days of exposure to oral hymecromone, healthy human subjects experienced a significant reduction in sputum HA levels, indicating this oral therapy may have potential in pulmonary diseases where HA is implicated in pathogenesis.TRIAL REGISTRATIONClinicalTrials.gov NCT02780752.FUNDINGStanford Medicine Catalyst, Stanford SPARK, Stanford Innovative Medicines Accelerator program, NIH training grants 5T32AI052073-14 and T32HL129970.

Keywords: Extracellular matrix; Inflammation.

Figure 1. CONSORT diagram of study enrollment.

Open-label, single-center, nonrandomized, dose-response study of hymecromone in healthy adults. Participants were assigned to receive hymecromone at 1200 mg/d, 2400 mg/d, or 3600 mg/d. First, participants were assigned to 1 of 2 study arms: 2400 mg/d or 3600 mg/d; participants were assigned to dose arms in a sequential manner until 6 participants were enrolled in each arm. Second, participants were invited to reenroll to complete either 1 or 2 additional dose arms. The first 6 individuals who volunteered to reenroll for 2 additional doses were first assigned to the high-dose arm opposite of what they received in the first enrollment and then received 1200 mg/d for their third enrollment. Additional individuals who volunteered to reenroll for 1 additional dose were assigned to the 1200 mg/d arm.

Figure 2. Sputum HA decreases after treatment with 4-MU.

(A) Sputum 4-MU levels demonstrated a stepwise increase with increasing dose. One extreme outlier in the 2400 mg arm was removed from this graph. (B) Sputum 4-MUG levels demonstrated a dose-dependent increase. (C) Mean sputum HA decreased across all 3 arms. The change was statistically significant in the 1200 mg and 3600 mg arms. (D) Higher baseline sputum HA levels showed a greater response to treatment. *P < 0.05, difference from baseline to day 4 of treatment by paired t test; ^#P < 0.05, difference between dose arms by unpaired t test. The dashed line indicates the baseline reference level. In all panels, n = 8, n = 9, and n = 9 for the 1200 mg, 2400 mg, and 3600 mg arms, respectively. Each boxplot represents the median, interquartile range, 1.5 times the interquartile range, and data points outlying the whisker range.

Figure 3. Serum HA decreases after treatment with 4-MU.

(A) Serum 4-MU and (B) serum 4-MUG levels demonstrated a stepwise increase with increasing dose. (C) Serum HA decreased significantly in the 1200 mg arm only; this was also significantly different from the 3600 mg arm. (D) Higher baseline serum HA levels showed a greater response to treatment. *P < 0.05, difference from baseline to day 4 of treatment by paired t test; ^#P < 0.05, difference between dose arms by unpaired t test. The dashed line indicates the baseline reference level. In all panels, n = 8, n = 9, and n = 9 for the 1200 mg, 2400 mg, and 3600 mg arms, respectively. Each boxplot represents the median, interquartile range, 1.5 times the interquartile range, and data points outlying the whisker range.