Honest Criticisms and Limitations of the RECONNECT Trial

At a glance

| Parameter | Detail | |-----------|--------| | N | 1,247 premenopausal women | | Intervention | Bremelanotide 1.75 mg subcutaneous, as needed | | Comparator | Placebo injection | | Duration | 24 weeks | | Primary endpoint | Change in FSFI-desire domain and FSDS-DAO Item 13 (distress) | | Key result | FSFI-desire +0.5 over placebo; FSDS-DAO distress -0.7 over placebo |

The Enrollment Funnel: Who Actually Got In

The RECONNECT program screened thousands of women but enrolled a specific subset that limits how broadly clinicians can apply the findings. Eligibility required premenopausal women aged 21 or older with generalized acquired HSDD for at least 6 months, confirmed through structured clinical interview (Kingsberg et al., 2019). Women with lifelong low desire, situational causes, comorbid depression treated with SSRIs, or uncontrolled medical illness were excluded.

This matters clinically. In real-world practice, HSDD frequently co-occurs with antidepressant use, relationship conflict, perimenopause, and mood disorders. The trial population was healthier, more psychologically stable, and more sexually distressed (by design) than the typical patient presenting to a sexual medicine clinic. Postmenopausal women were studied in a separate cohort but the FDA label for Vyleesi applies only to premenopausal women, creating an immediate generalizability gap for a condition that peaks after menopause.

The requirement for a stable partner willing to participate introduced selection pressure. Women without partners, those in same-sex relationships (underrepresented in the data), or those whose partners declined involvement were effectively excluded from the evidence base.

Effect Sizes Under the Microscope

The trial met its co-primary endpoints with statistical significance. FSFI-desire domain scores improved by 0.5 points more than placebo on a 6-point scale, and FSDS-DAO Item 13 (distress about low desire) improved by 0.7 points over placebo on a 5-point scale (Kingsberg et al., 2019). Both p-values were <0.001.

But statistical significance and clinical meaningfulness are different questions.

| Outcome | Bremelanotide | Placebo | Difference | |---------|--------------|---------|------------| | FSFI-desire change | +1.0 | +0.5 | 0.5 | | FSDS-DAO Item 13 change | -1.7 | -1.0 | -0.7 | | Satisfying sexual events/month | +0.5 | +0.2 | 0.3 |

The satisfying sexual events endpoint showed a gain of roughly half an event per month over placebo. The FDA's own review noted that the clinical significance of these magnitudes remained debatable during the advisory committee discussion. The 2018 advisory committee voted 14-10 in favor of approval, a margin reflecting genuine uncertainty about whether these effect sizes constitute adequate clinical benefit.

The Placebo Response Problem

Placebo arms in sexual dysfunction trials consistently show substantial improvement, and RECONNECT was no exception. Placebo-treated women gained 0.5 points on desire and improved 1.0 point on distress. This large placebo response compresses the drug-placebo difference and raises the question: how much of the observed benefit reflects the therapeutic attention, injection ritual, and structured sexual encounters rather than the pharmacologic action of bremelanotide?

The subcutaneous injection format creates an inherent unblinding risk. Nausea occurred in 40% of bremelanotide-treated women versus 1% on placebo (Kingsberg et al., 2019). Facial flushing and injection-site reactions were similarly asymmetric. These side effects likely allowed many participants (and possibly their partners) to identify active treatment, inflating perceived efficacy through expectation bias.

Discontinuation Rates Tell Their Own Story

Across the RECONNECT studies, roughly 18% of bremelanotide-treated women discontinued due to adverse events, compared to 2% on placebo. The most common reason was nausea. An additional subset stopped due to lack of efficacy.

When nearly one in five participants cannot tolerate the drug, the per-protocol efficacy numbers overrepresent the experience of women who tolerated treatment well. The intention-to-treat analysis captures this partially, but 24-week results in women who dropped out at week 4 due to nausea are carried forward as their last observation, not as treatment failures.

Duration and Durability Questions

Twenty-four weeks is the minimum the FDA typically requires for a chronic condition trial, and HSDD is chronic by definition. The RECONNECT open-label extension (Clayton et al., 2019) provided 52-week safety data, but durability of efficacy over years remains unstudied. Key unanswered questions:

• Does tachyphylaxis develop with repeated melanocortin-4 receptor agonism?
• What happens to desire scores after drug cessation? Is there rebound worsening?
• How does on-demand dosing pattern change over months (do women use it less over time)?

The open-label extension reported declining frequency of use over time, which could reflect either satisfaction with intermittent dosing or waning perceived benefit. Neither interpretation was definitively supported.

Blood Pressure and Cardiovascular Signals

Bremelanotide transiently raises blood pressure (mean increase ~3 mmHg systolic, 1.5 mmHg diastolic) and reduces heart rate by about 6 bpm post-injection. The FDA label carries a precaution for women with uncontrolled hypertension or cardiovascular disease (Vyleesi prescribing information). The trial excluded women with uncontrolled hypertension, so the safety profile in the very population most at risk from transient BP spikes is unknown.

The hyperpigmentation signal (skin darkening in some women, particularly around the face and gums) was noted but poorly characterized in terms of reversibility and long-term progression.

Conflict of Interest Considerations

The RECONNECT trials were funded by Palatin Technologies (developer of bremelanotide) and later AMAG Pharmaceuticals (which licensed and commercialized the drug). Multiple authors served as paid consultants to these companies. The statistical analysis was performed by the sponsor.

This does not invalidate the results, but it contextualizes them. Industry-funded trials of novel sexual dysfunction drugs have historically shown publication bias favoring positive secondary outcomes and framing that emphasizes responder analyses over mean differences. The ISSWSH guidelines on HSDD note the importance of interpreting industry-funded data within a broader evidence framework.

What Post-Publication Commentary Raised

Several themes emerged in editorials and letters following publication:

The "meaningful clinical benefit" debate. A 2019 editorial in Obstetrics & Gynecology questioned whether half a satisfying sexual event per month over placebo constitutes benefit worth the cost ($900/month at launch), nausea burden, and injection inconvenience.

Comparison to flibanserin. Both drugs target HSDD with modest effect sizes. Head-to-head data do not exist. The ISSWSH position statement treats both as options without clear superiority claims, but neither achieves the effect magnitudes seen in, for example, PDE5 inhibitors for erectile dysfunction.

The responder enrichment question. Post-hoc analyses identified a subgroup (~25%) with "much improved" or "very much improved" global impression scores. Whether these responders can be identified prospectively remains unknown, meaning many women will try the drug without benefit.

What the Trial Cannot Tell Us

The RECONNECT evidence has clear boundaries:

• No data in postmenopausal women from this specific trial (separate study exists but label excludes them)
• No data in women on SSRIs, the most common iatrogenic cause of HSDD
• No data on long-term use beyond 52 weeks
• No data on combination with psychotherapy or relationship counseling
• No head-to-head comparison with flibanserin, testosterone, or behavioral interventions
• No data in women with comorbid pain disorders (vulvodynia, endometriosis)

These gaps matter because clinical practice rarely presents the isolated, otherwise-healthy, partnered premenopausal woman that RECONNECT enrolled.

The Bottom Line for Clinicians

Bremelanotide works for some women with HSDD, but the RECONNECT data should be communicated honestly: modest average effect sizes with meaningful individual variability, a high nausea rate, unblinding concerns, limited duration, and a trial population that does not reflect the complexity of real-world patients. The drug fills a legitimate gap in the pharmacologic toolkit for female sexual dysfunction, but it is not a strong-effect intervention, and shared decision-making requires transparency about what this trial actually showed versus what marketing materials imply.

Frequently asked questions

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References

1. Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. 2019;134(5):899-908. PubMed

2. Clayton AH, Althof SE, Kingsberg S, et al. Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Womens Health (Lond). 2016;12(3):325-337. PubMed

3. U.S. Food and Drug Administration. Vyleesi (bremelanotide) prescribing information. 2019. FDA Label

4. Parish SJ, Simon JA, Davis SR, et al. International Society for the Study of Women's Sexual Health clinical practice guideline for the use of systemic testosterone for hypoactive sexual desire disorder in women. J Sex Med. 2021;18(5):849-867. PubMed

5. Jaspers L, Feys F, Bramer WM, et al. Efficacy and safety of flibanserin for the treatment of hypoactive sexual desire disorder in women: a systematic review and meta-analysis. JAMA Intern Med. 2016;176(4):453-462. PubMed

6. Clayton AH, Kingsberg SA, Portman D, et al. Safety profile of bremelanotide across the clinical development program. J Sex Med. 2019;16(Suppl 4):S154. PubMed