Trial Comparing Subcutaneous Natural Progesterone (Prolutex) vs. Cetrorelix Acetate for Luteinizing Hormone Surge Suppression in Freeze-All IVF Cycles.

Title: A Non-Inferiority Randomized Controlled Trial Comparing Subcutaneous Natural Progesterone (Prolutex) vs. Cetrorelix Acetate for Luteinizing Hormone Surge Suppression in Freeze-All IVF Cycles.

1. Principal Investigator:

Prof. Ahmed Elbohoty, MSc, MD, FRCOG, EFRM Trust Fertility Clinic, Abu Dhabi, UAE Email: ahmed.elbohoty@trustfertility.com

Co-Investigators:

Dr Walid Sayed - Group Medical Director Trust Fertility Clinic Dr Irfan Aslam - Group IVF Lab director Trust Fertility Clinic Dr Amani Kanan - Specialist Obstetrics and Gynaecology Dr Nayrouz Gezaf - Specialist Obstetrics and Gynaecology Study Registration: To be registered on ClinicalTrials.gov Ethics Approval: To be approved by the Institutional Review Board (IRB) of Burjeel Holdings

Standard IVF Procedures Under Institutional Coverage:

All procedures-ovarian stimulation, hormone monitoring, and oocyte retrieval-are identical to routine clinical practice already being conducted at Trust fertility clinic - Burjeel Medical City.

Participants will receive the same monitoring and safety precautions as standard IVF patients.

No additional interventions will be introduced, and all clinical care will remain within the framework of the institution's established protocols.

Both the investigators and the institution are covered under existing malpractice and liability insurance policies, which apply to all routine fertility procedures.

Ethical Safeguards in Place:

Participants will provide detailed informed consent, outlining all aspects of the protocol, including the use of approved medications and the lack of deviation from standard care. 2. Background: The prevention of premature luteinizing hormone (LH) surge during controlled ovarian stimulation (COS) is critical for optimizing outcomes in assisted reproductive technology (ART). Cetrorelix acetate, a GnRH (Gonadotropin releasing hormone) antagonist administered subcutaneously, is the current standard for luteinizing hormone suppression. However, natural progesterone in a novel subcutaneous formulation (Prolutex) may offer a viable alternative.

Prolutex is a water-soluble complex of natural progesterone with hydroxypropyl-β-cyclodextrin (HPBCD), patented as US Patent No. 4,727,064 (Pitha, J.), allowing for subcutaneous injection. This may simplify treatment and improve patient compliance.

Progesterone forms are well studied and used globally/in UAE to suppress Luteinizing Hormone surge. It is an example of off-label use, which becomes a standard indication for use of progesterone. Several studies have demonstrated that exogenous progesterone can effectively suppress Luteinizing Hormone release while maintaining follicular development and oocyte competence. Furthermore, progestin-based protocols are potentially more cost-effective and similar to administer compared to GnRH (Gonadotropin releasing hormone) antagonists.

To our knowledge, this is the first randomized trial directly comparing a subcutaneous progesterone formulation (Prolutex) with cetrorelix acetate, administered via the same route, in terms of luteinizing hormone surge suppression. For this specific research, there are no relevant published studies available. This Randomised controlled trial will be done to address the research gap and compare the two already approved standard of care medications to see if Prolutex can be used as a viable alternative to suppress Luteinizing Hormone levels.

Study Objectives:

Primary Objective:

To evaluate whether subcutaneous natural progesterone (Prolutex) is non-inferior to Cetrorelix Acetate in preventing premature ovulation in freeze-all IVF cycles. 3. Secondary Objectives:

To compare the number of retrieved oocytes, MII rate, fertilization rate, and blastocyst formation rate To assess duration of ovarian stimulation To monitor hormone levels (luteinizing hormone, estradiol, progesterone) To evaluate patient tolerability, comfort, and adherence To compare cost-effectiveness of both protocols

Study Design:

Design: Prospective, Phase IV, randomized, open-label, non-inferiority trial Setting: Trust Fertility Clinic, Abu Dhabi, UAE Randomization: 1:1 block randomization, stratified by age and ovarian reserve

Arms:

Control Group (A): Cetrorelix acetate 0.25 mg Subcutaneously daily from day 5 to trigger Test Group (B): Natural progesterone 25 mg Subcutaneously (Prolutex) daily from day 5 to trigger 4. Sample Size Justification:

Based on previous studies, the incidence of premature ovulation in GnRH (Gonadotropin releasing hormone) antagonist cycles is \~5% (Griesinger et al., 2016; Vuong et al., 2021). A non-inferiority margin of 5% (i.e., 10% total threshold) is selected, aligned with clinical tolerance standards (Fatemi et al., 2019). With α = 0.05 (one-sided) and 80% power, the minimum sample required is 102 per group. Allowing for a 10% dropout, the total enrolment target is 230 participants (115 per group).

Data will be populated in excel and the data collection form will be attached to the participant file and upload to the secure study database. 5. Eligibility Criteria:

Inclusion Criteria:

Women aged 18-40 years Body Mass Index \< 35 kg/m² Antral Follicle Count ≥ 8 or Anti-Müllerian Hormone ≥ 1.2 ng/mL Undergoing freeze-all IVF (for Ovarian Hyperstimulation Syndrome - OHSS risk, PGT- Preimplantation Genetic Testing, or personal preference)

Exclusion Criteria:

Poor responders (Bologna criteria) Stage III-IV endometriosis Pituitary or hypothalamic dysfunction Planned fresh embryo transfer Severe Male Factor. Semen Count \<1 ×〖10〗\^6 (\<1 Million/ml) or Azoospermia) 6. Stimulation Protocol:

Stimulation:

Ovarian stimulation will begin between Cycle Day 2 and Cycle Day 5 of spontaneous or withdrawal-induced menstruation, as determined by physician assessment and baseline ultrasound and hormonal evaluation.

Ovarian stimulation will be performed using human menopausal gonadotropin (HMG) or recombinant FSH, based on physician discretion and patient characteristics.

Starting dose (typically 150-300 IU daily) will be individualized based on age, BMI (body mass index), AMH (Anti Mullerian Hormone), and Antral Follicle Count The choice of gonadotropin will be documented, and distribution between study arms will be analyzed to ensure balance.

LUTEINIZING HORMONE Suppression:

Cetrorelix acetate 0.25 mg Subcutaneously (control) Natural progesterone 25 mg Subcutaneously (Prolutex) (intervention) Starting on stimulation day 5 until the day of ovulation trigger Trigger: Either Triptorelin 0.2 mg Subcutaneously or recombinant hCG (Human Chorionic Gonadotropin), per physician assessment Oocyte Retrieval: 36 hours post-trigger Embryo Handling: Blastocyst culture followed by vitrification for all embryos (with or without embryo biopsy)

Standard IVF Procedures Under Institutional Coverage:

All Procedures - ovarian stimulation, hormone monitoring, and oocyte retrieval - are identical to routine clinical practice already being conducted at Trust Fertility Clinic - Burjeel Medical City.

Participants will receive the same monitoring and safety precautions as standard IVF patients.

No additional interventions will be introduced, and all clinical care will remain within the framework of the institution's established protocols.

The study treatment and assessments will be covered by patient medical insurance/self-pay as these are considered standards of care. There are no additional expected risks beyond what the participants would typically encounter in a standard IVF cycle, in which case patient will receive appropriate medical care from the hospital in line with their insurance/self-pay coverage. 7. Monitoring and Hormonal Assessment:

• secondary outcomes [Time frame: 2 weeks after stimulation]
• maturation rate [Time frame: 2 weeks after stimulation]
• • Fertilization rate [Time frame: 2 days after egg collection]
• • Blastocyst formation rate [Time frame: 3 weeks after stimulation]
• • Duration of stimulation (in days) [Time frame: 10 to 14 days from start]
• • Hormonal profile (Luteinizing Hormone, Estradiol, Progesterone) [Time frame: 2 weeks duration from start of stimulation]