RE104 Shows Rapid & Durable Relief in Postpartum Depression

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Published: August 18, 2025 (Topline Phase 2 Results, Reunion Neuroscience)
Study: RECONNECT Phase 2 Clinical Trial of RE104 for Postpartum Depression (PPD)

Postpartum depression (PPD) affects nearly 500,000 women annually in the U.S., with around 15% of new mothers experiencing moderate-to-severe symptoms. Current treatments—SSRIs, brexanolone, and zuranolone—are limited by delayed onset, high cost, or treatment burden.

  • RE104, a novel psychedelic-inspired therapy, is designed to provide rapid, durable relief with a single subcutaneous injection.
  • Unlike psilocybin or LSD, RE104 produces a short psychoactive effect (3–4 hours), potentially making it more practical in outpatient care.

Mechanism of Action:

RE104 is a prodrug of 4-OH-DiPT (4-hydroxy-diisopropyltryptamine), a serotonin 5-HT₂A receptor agonist.

  • Produces fast-acting antidepressant effects similar to psilocybin.

  • Designed for a short psychoactive window (3–4 hours), reducing caregiver disruption compared to longer psychedelic experiences.

  • Single-dose efficacy may help overcome adherence challenges common in PPD.

RECONNECT Phase 2 Trial Results:

 Design:

  • Multicenter, randomized, double-blind, active dose-controlled study (38 U.S. sites)

Population:

  • 84 women

  • ages 21–45,

  • average postpartum 7.3 months (range: 1.5-17.7)

  • HAMD-17 of ≥24

Intervention:

  • Single 30 mg subcutaneous dose of RE104 vs
  • active control (1.5 mg RE104)
  • Psychotherapy: Not provided in this trial

Key Outcomes:

  • Primary Endpoint (Day 7):

    • 30 mg dose: –23.0 MADRS points

    • Control: –17.2 MADRS points

    • Difference: –5.8 points (p = 0.0094)

  • Rapid Effect: Clinically meaningful MADRS reduction observed Day 1, sustained through Day 28.

  • Response and Remission (Day 7):

    • Response (≥50% MADRS reduction): 77.1% vs 61.6%

    • Remission (MADRS ≤10): 71.4% vs 41.0%

    • Benefits maintained through Day 28.

  • Maternal Functioning: Significant improvement on the Barkin Index of Maternal Functioning (BIMF), reflecting better daily caregiving capacity.

  • Discharge Readiness: 92.7% of patients were ready to leave within 4 hours, supporting outpatient feasibility.

  • Safety:

    • Most common AEs: nausea (43.9%), headache (34.1%)—mild/moderate, transient.

    • No serious adverse events (SAEs).

    • No suicidal ideation, seizures, serotonin toxicity, or ECG abnormalities reported.

  • Breastfeeding Safety: Lactation study showed <0.1% of maternal dose in breast milk, suggesting mothers may resume breastfeeding quickly after treatment.

Comparison With Current & Emerging Treatments

TreatmentOnsetModeLimitations
SSRIs (e.g., sertraline)4–6 weeksDaily oralSlow onset, adherence issues
Brexanolone (Zulresso®)~60 hoursContinuous IV infusionHigh cost, inpatient administration
Zuranolone (Zurzuvae®)~2 weeksDaily oral (14 days)Expensive (~$16k), driving/safety restrictions
RE104 (Phase 2)Day 1Single SC injectionStill investigational; nausea/headache most common

Unique Advantages of RE104:

  • Ultra-rapid onset (within 24 hours)

  • Single-dose therapy (vs weeks of dosing)

  • Short psychedelic effect (3–4 hours)

  • High response/remission rates (70%+ at Day 7)

  • Minimal impact on breastfeeding

What’s Next?

  • Phase 3 PPD trial planned for 2026

  • Expansion to other conditions: Adjustment disorder in cancer patients (Phase 2 REKINDLE trial starting Q3 2025), plus another major psychiatric indication in early 2026.

Clinical Takeaway

The RECONNECT Phase 2 trial positions RE104 as a groundbreaking therapy for postpartum depression:

  • Rapid, durable relief with a single outpatient-administered dose

  • Safe, tolerable, and breastfeeding-compatible

  • Could become a new standard of care if Phase 3 confirms results

For clinicians managing PPD, RE104 may represent a paradigm shift—offering patients and families hope for faster, more accessible recovery.

FOR ACADEMY MEMBERS:

WOMEN'S MENTAL HEALTH:
PREGNANCY, POST-PARTUM & PERI-MENOPAUSE:

  • Antipsychotics
    • Antipsychotics During Pregnancy & Postpartum
    • Antipsychotics: Rates of Placental Passage
    • Antipsychotics of Choice during Lactation
  • Antidepressants
    • Zuranolone FDA Approved for Postpartum Depression
    • Antidepressants During Pregnancy & Postpartum
    • Antidepressants of Choice during Lactation
    • RE104 for Postpartum Depression (2025 Data)
  • Mood Stabilizers
    • Preconception Planning: Preparing for Pregnancy
    • Continue or Discontinue Medication during Pregnancy & Postpartum?
    • Lithium: During Pregnancy & Postpartum
    • Lithium: use during Lactation
    • Valproate: During Pregnancy & Postpartum
    • Lamotrigine: During Pregnancy & Postpartum
    • Other Mood Stabilizers: During Pregnancy & Postpartum
    • Other Mood Stabilizers: use during Lactation
  • Benzodiazepines
    • Benzodiazepines: During Pregnancy & Postpartum
  • ADHD Medication
    • ADHD Medication & Brestfeeding
  • Postpartum Onset OCD
    • Postpartum Onset OCD
  • Postpartum Psychosis
    • Postpartum Psychosis: Evaluation & Management
  • Perimenopausal Depression
    • Perimenopausal Depression
  • PMDD
    • PMDD

Women’s Mental Health (Pregnancy, Post-partum & Peri-menopause)

[FOR ACADEMY MEMBERS ONLY]
ACADEMY

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