Biomarker-guided rTMS for Treatment Resistant Depression

Major depressive disorder (MDD) is a leading cause of global disability, and approximately 30% of MDD patients are resistant to antidepressant pharmacotherapy. Repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC) is an FDA-cleared intervention with proven efficacy in treatment-resistant depression, but only 30-40% of these patients achieve remission after a single course. Other studies have shown that rTMS targeting the dorsomedial prefrontal cortex (DMPFC) is comparably effective, but biomarkers for informing target site selection do not exist. Diagnostic heterogeneity has been an obstacle to biomarker discovery efforts. Recently, we developed and validated an approach to diagnose four novel MDD subtypes or "biotypes' defined by resting state functional connectivity (RSFC) patterns and predicting differing antidepressant responses at the individual level to rTMS. This pivotal trial will test a novel, biotype-guided treatment selection strategy motivated by the hypothesis that an individual patient's likelihood of responding to left DLFPC vs.DMPFC rTMS is determined in part by individual differences in 1) the degree to which their symptoms are driven by dysfunction in specific cerebral network targets comprising Valence Systems; and 2) the degree to which dysfunction in those targets can be modulated by stimulating the left DLPFC or DMPFC. Subjects (N=348; 174 from this site) will be randomized to receive a) biotype-guided rTMS targeting the DMPFC or left DLPFC; b) to a disconfirmation arm receiving rTMS targeting the opposite site; and c) to a third arm receiving FDA-cleared, standard-of-care rTMS targeting the left DLFPC, regardless of biotype. The dosage and method of delivery of rTMS for all arms are as follows: intermittent theta burst stimulation (iTBS) will be delivered at 120% of the resting motor threshold. It will be administered in triplet 50 Hz bursts, repeated at 5 Hz with a duty cycle of 2 s on and 8 s off, for a total of 600 pulses per session and a total duration of 3 min 9 s. All patients will be assessed before and after treatment on a battery of fMRI, behavioral, and clinical assessments. The primary goal is to confirm the efficacy of a novel RSFC biomarker-guided approach to differential treatment selection in treatment resistant depression.