An Open-Label Extension Study to Evaluate the Safety and Tolerability of SPT-300 (GlyphAllo) in Participants With Major Depressive Disorder, With or Without Anxious Distress (BUOY-1 OLE Study)

This is an open-label, monotherapy, extension study to evaluate the safety and tolerability of SPT-300 (GlyphAllo) in adults with major depressive disorder (MDD), with or without anxious distress.

Inclusion Criteria: * Participant who completed treatment in Study SPT-300-2024-203 (i.e., participant who competed Visit 8 \[Day 42\] of Study SPT-300-2024-203 \[BUOY-1 Study\]). * Women of childbearing potential (WOCP) must not plan to become pregnant during the course of the study or be currently breastfeeding. WOCP must agree to use a highly effective form of contraception during participation in the study and for 30 days after receiving the last dose of study treatment. * Participant is willing and able to refrain from the use of drugs of abuse. Exclusion Criteria: * Participants who, in the opinion of the Investigator, medical monitor, or Sponsor, should not participate in the study. * Participants who, in the judgment of the Investigator, were noncompliant with trial procedures or with study treatment administration during the double-blind study (BUOY-1 Study). * Female participants with a positive urine pregnancy test result. Female participants may be enrolled without a negative urine test if they are surgically sterile or at least 2 years post-menopause.