Predictive Biomarkers of Dyspnea Response to Dexamethasone and Placebo in Cancer Patients

In the Alleviating Breathlessness in Cancer Patients with Dexamethasone (ABCD) trial, dexamethasone did not improve dyspnea more than placebo in unselected cancer patients. However, it is unclear if patients with greater inflammation would be more likely to derive a treatment response.

To examine the predictive utility of cytokines for dyspnea response.

We performed a secondary analysis of the ABCD double-blind, randomized clinical trial comparing high-dose dexamethasone to placebo (NCT03367156). The primary outcome was dyspnea intensity over 14 days. Blood cytokine levels (TNF, IL-6, IL-8, and IL-10) were measured at baseline, day seven, and day 14. We used a generalized additive model to examine the association between baseline cytokine level and change in dyspnea from baseline to day seven and baseline to day 14 in dexamethasone and placebo groups.

Of the 128 enrolled patients, 45 provided blood samples. TNF, IL-6, and IL-8 decreased over 14 days in the dexamethasone group but not placebo (P<0.05). Lower baseline TNF was associated with a greater reduction in dyspnea intensity by day seven in the placebo group (P=0.0013); conversely, higher baseline TNF was associated with a greater reduction in dyspnea intensity by day 7 in the dexamethasone group (difference between groups P=0.0019). Similar patterns were observed for IL-6 (P=0.000051), IL-8 (P=0.00063), and IL-10 (P=0.01) on day seven, and all cytokines on day 14.

Cytokines decreased with dexamethasone, but not placebo. Higher baseline cytokine levels may identify patients likely to respond to dexamethasone and less likely to respond to placebo.