Background: Prior studies suggested that less than 20% improvement at week 2 predicted worse final response rates but lacked deep Transcranial Magnetic Stimulation (dTMS) data. This study intended to verify whether varying degrees of improvement in Major Depressive Disorder at weeks 2 and 6 accurately predicted response and remission rates at Endpoint, and benefits of treatment past week 6. Methods: All patients (n=169) in this open-label, retrospective study received at least 30 sessions of dTMS using 55 to 95 two-second trains, frequency 18 Hz, 120% motor threshold over the left dorsolateral prefrontal cortex (DLPFC). Augmentation included left DLPFC intermittent Theta Burst Stimulation (iTBS) and right DLPFC Low Frequency dTMS. Responders improved by 50% from baseline on the Hamilton Depression Scale (HAMD). Patients were grouped as “Improvers” or “Non-Improvers” based on improvement at weeks 2 and 6, then compared to Endpoint. Results: After week 2, those improved by over 30% had significantly higher endpoint remission rates. Those improved by 15-40% after week 2 had significantly higher endpoint response rates. After week 6, those improving by 15-40% showed both significantly higher Endpoint response and remission rates. Conclusions: 56% and 35% of Non-Improvers with less than 20% improvement after Weeks 2 and 6, respectively, responded at Endpoint. With such a large portion of patients responding after Week 6, treatment extension beyond week 6 may be warranted on a per patient basis. Conflicts of Interests: None Funding: None Disclosures: Dr. Kinback is the Owner and Medical Director of Advanced TMS Center, a private group psychiatric practice in Ladera Ranch, CA. He is a board member, past Treasurer and Fellow of the Clinical TMS Society. He has received stipends in the past for speaking from the Clinical TMS Society.