Soleno Therapeutics SLNO
Scorpion petitions FDA to recall Soleno's VYKAT XR after 7 hospitalizations for fluid overload/potential heart failure in children and alleged safety-data manipulation invalidate the drug's risk-benefit.
Thesis
Scorpion Capital formally petitions the FDA to recall Soleno Therapeutics' VYKAT XR (diazoxide choline ER), approved March 2025 for Prader-Willi hyperphagia. Within weeks of launch, seven patients — an estimated ~135 total on drug — have been hospitalized for pulmonary/cardiac complications, including an 11-year-old who spent seven weeks in the hospital with a week on a ventilator. Scorpion argues diazoxide mechanistically causes fluid retention that monitoring, slower titration, and diuretics cannot prevent; only discontinuation works, per Desai 2021 and Timlin 2017. The firm also alleges Soleno obscures the signal: edema rates in the FDA label (27%/12%) contradict the Phase 3 paper (20.2%/9.5%), DEXA scans conflate fluid with lean body mass, ECG results are buried, and the 77-patient withdrawal study's last-minute p=0.049 strains credibility. The petition demands recall, a public health advisory, and an Ad Comm.
SCQA
VYKAT XR is Soleno's first-ever drug launch, FDA-approved March 2025 for hyperphagia in Prader-Willi syndrome; Soleno is a 131-employee company with ~135 commercial patients on drug.
Seven pediatric hospitalizations for pulmonary/cardiac fluid-overload events have emerged within weeks of launch; diazoxide-induced edema is non-dose-dependent, cannot be mitigated by diuretics or monitoring, and Soleno's safety disclosures appear manipulated.
FDA should request a voluntary market recall of VYKAT XR, issue a public health advisory to prescribers and caregivers, and convene an Advisory Committee with PWS trial investigators to review the drug's safety and efficacy.
Removing VYKAT XR from market prevents further pediatric ICU admissions and potential fatalities from congestive heart failure; implicitly, Soleno's equity value — entirely dependent on VYKAT XR — would collapse, rewarding Scorpion's short position.
The three reasons
- 1
7 hospitalizations out of ~135 patients within weeks of launch signals a post-marketing crisis
- 2
Diazoxide-induced fluid retention cannot be mitigated by diuretics — only discontinuation works
- 3
Label edema data (27%/12%) contradicts Phase 3 paper (20.2%/9.5%), suggesting data misconduct
Primary demands
- FDA request a voluntary recall of VYKAT XR from the US market
- FDA issue a formal public health advisory to prescribers, patients, caregivers
- FDA take additional regulatory/enforcement actions (e.g. compassionate use + REMS)
- FDA convene an Advisory Committee to review VYKAT XR's safety and efficacy
KPIs cited
Pattern membership
Precedents cited
- Scorpion 2023 Citizen Petition on Harmony Biosciences / Wakix (pitolisant)
- Scorpion 2025 Citizen Petition on TransMedics Organ Care System
- Desai et al 2021 (diazoxide NICU safety review)
- Timlin et al 2017 (diazoxide pulmonary hypertension case series)
Slide gallery ·
Notes
Short companion to Scorpion's 415-page SLNO1 investigative report (Aug 15, 2025). Submitted as FDA Citizen Petition on Aug 21, 2025 — a regulatory-pressure tactic alongside the public short thesis. Pure-text letter format, no charts or branding. Signatory is Kir Kahlon, Scorpion's founder/CIO. Primary rhetorical moves: (1) CEO-quote contradiction — Aug 6 earnings call denial of new safety signals vs 7 hospitalizations disclosed Aug 18 in Guggenheim note; (2) literature-based argument that diuretics/monitoring cannot mitigate diazoxide-induced fluid retention; (3) data-integrity allegations — mismatched edema figures between FDA label and Phase 3 paper, buried ECG results, unpublished withdrawal study, suspicious last-minute p=0.049. Precedent-chains to prior Scorpion petitions (Harmony/Wakix 2023; TransMedics 2025) to establish credibility with FDA. No stake disclosed and no explicit price target — campaign outcome in progress as of filing date.