Cyrano Therapeutics' CYR-064 shows positive Phase II results in persistent post-viral smell loss

# Cyrano Therapeutics Reports Positive Phase II Data for CYR-064 in Persistent Smell Loss Florida-based Cyrano Therapeutics [announced](https://www.prnewswire.com/news-releases/cyrano-therapeutics-announces-positive-topline-results-from-phase-2-flavor-trial-of-cyr-064-a-proprietary-and-potential-first-to-market-regenerative-therapy-for-persistent-smell-loss-302689451.html) positive topline results from its Phase II FLAVOR trial evaluating CYR-064, an intranasal broad-spectrum phosphodiesterase (PDE) inhibitor, in patients with persistent post-viral hyposmia — a condition for which no pharmacotherapy is currently approved. The randomized, placebo-controlled study met its primary safety endpoint and key prespecified secondary efficacy endpoints, with the company reporting durable improvements in smell function. If the findings hold in a larger trial, CYR-064 could become the first regulated pharmaceutical treatment for the millions of people worldwide living with persistent smell loss after viral infection, a population that expanded substantially during the COVID-19 pandemic. ## Trial specifics The [FLAVOR trial](https://www.prnewswire.com/news-releases/cyrano-therapeutics-announces-positive-topline-results-from-phase-2-flavor-trial-of-cyr-064-a-proprietary-and-potential-first-to-market-regenerative-therapy-for-persistent-smell-loss-302689451.html) was a randomized, double-blind, placebo-controlled Phase II study that enrolled 151 patients with persistent post-viral hyposmia lasting at least six months across 14 clinical sites in the United States. CYR-064 was administered as a patent-protected intranasal soft-mist spray, though specific dose levels, dosing frequency, and the duration of the double-blind treatment period were not disclosed in the topline announcement. The randomization ratio was also not specified. The trial's primary endpoint was safety and tolerability. On that measure, the company reported no treatment-related serious adverse events. Across multiple prespecified secondary efficacy endpoints, CYR-064 demonstrated what the company described as durable improvements in smell function. Specific numerical results — including effect sizes, p-values, and the particular psychophysical smell tests used — were not released. Cyrano said it intends to present detailed data at an upcoming medical conference in 2026. Rick Geoffrion, President and CEO of Cyrano Therapeutics, stated: "This is the first randomized, controlled trial to show a pharmaceutical agent can safely improve smell function in patients with persistent post-viral hyposmia." He added that "once a person has lost their sense of smell for as long as 6 months, the chances become extremely small that their sense of smell will return," and noted that loss of smell also eliminates up to 80% of taste perception. Mas Takashima, Chairman of the Department of Otolaryngology at Houston Methodist Hospital and the trial's primary investigator, said the results showed CYR-064 "may one day become the first front-line treatment for this serious condition." On the basis of the Phase II CYR-064 Phase 2 results, the company said it plans to advance CYR-064 into Phase III development in the second half of 2026. No specific regulatory filing timeline was disclosed, and no open-label extension study was mentioned. ## Research context CYR-064 is formulated as an intranasal soft-mist spray containing a broad-spectrum PDE inhibitor paired with a proprietary delivery system designed to reach the olfactory epithelium in the nasal cavity. The mechanistic rationale centers on the role of cyclic nucleotide signaling in olfactory sensory neurons. PDE enzymes degrade cyclic AMP and cyclic GMP, second messengers that are central to the signal transduction cascade triggered when odorant molecules bind to olfactory receptors. By inhibiting PDE activity at the olfactory epithelium, CYR-064 is intended to enhance neuronal excitability and, according to the company, promote regeneration of olfactory function. This mechanism is directly relevant to the pathology of post-viral hyposmia, in which viral-mediated damage to the olfactory neuroepithelium can impair both the sensory neurons themselves and the supporting sustentacular cells. Unlike many other neural tissues, the olfactory epithelium retains regenerative capacity throughout life, but in a subset of patients — particularly those whose smell loss persists beyond six months — recovery stalls. CYR-064 is positioned as a regenerative therapy aimed at reactivating this stalled recovery process. Post-viral hyposmia is estimated to affect more than 60 million people across the United States, Europe, and Japan, according to the company. The condition carries consequences beyond sensory impairment: published literature links persistent olfactory dysfunction to nutritional deficits, depression, safety hazards (inability to detect smoke, gas leaks, or spoiled food), and in older adults, increased risk of cognitive decline and mortality. The current standard of care is olfactory training — a structured regimen of repeated exposure to specific odors intended to leverage neuroplasticity — which has [demonstrated](https://pubmed.ncbi.nlm.nih.gov/19235739/) modest efficacy in some patients but is not a pharmacological intervention and has variable outcomes. No US FDA designations such as Fast Track, Breakthrough Therapy, or Orphan Drug status have been publicly disclosed for CYR-064. The molecule remains unapproved globally. Cyrano Therapeutics is a private, venture-backed company and does not appear to have disclosed any licensing or co-development partnerships for the asset. ## Competitive landscape for persistent smell loss treatment The field of pharmacotherapy for post-viral olfactory dysfunction is sparse. No drug is approved for this indication in any major market, and CYR-064 is the most advanced molecule in clinical development specifically targeting persistent smell loss through PDE inhibition. The closest mechanistic comparator — intranasal theophylline, a non-selective PDE inhibitor and methylxanthine — has been studied in academic settings but has not entered commercial development and produced mixed results in the most rigorous trial conducted to date. Key programs and comparators include: * **Intranasal theophylline** (academic-led, Washington University School of Medicine): A [randomized, placebo-controlled trial](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2813838) (NCT05015673) in approximately 51 patients with post-COVID olfactory dysfunction failed to meet its primary endpoint of change in University of Pennsylvania Smell Identification Test (UPSIT) score versus placebo. Earlier [open-label work](https://pubmed.ncbi.nlm.nih.gov/19359985/) by Robert Henkin had suggested potential benefit, but the controlled data were not confirmatory. No pharmaceutical company has advanced intranasal theophylline into pivotal development. * **Intranasal platelet-rich plasma (PRP)** (academic-led, multiple centers): Small pilot studies and randomized trials ([NCT04944225](https://clinicaltrials.gov/ct2/show/NCT04944225)) have explored injection of autologous PRP into the olfactory cleft to deliver growth factors and promote neuroepithelial regeneration. Results have been mixed, and the approach remains in early-stage investigation without commercial sponsorship. * **Intranasal sodium citrate** (academic-led, McGill University and others): A calcium chelation strategy intended to modulate olfactory receptor neuron signaling. Small [randomized studies](https://pubmed.ncbi.nlm.nih.gov/28221723/) have been conducted, but the approach has not advanced beyond early clinical investigation. * **Olfactory training** remains the de facto standard of care but is a behavioral intervention rather than a pharmacotherapy, with [published evidence](https://pubmed.ncbi.nlm.nih.gov/19235739/) supporting modest and variable benefit. No selective PDE4 inhibitors (such as roflumilast, approved for COPD) or PDE5 inhibitors (such as sildenafil) have entered clinical testing for olfactory dysfunction, despite theoretical mechanistic rationale based on PDE expression in olfactory tissue. The failure of intranasal theophylline to meet its primary endpoint in a controlled setting is a relevant data point for evaluating CYR-064's prospects. Cyrano has not disclosed how CYR-064's formulation, PDE isoform selectivity profile, or delivery technology differs from generic theophylline preparations used in academic trials, though the company's emphasis on its proprietary delivery system and patent-protected formulation suggests these are intended points of differentiation. Whether these differences translate into the efficacy signal reported in the FLAVOR trial — and whether that signal will replicate in a Phase III smell loss therapy clinical trial — will be the central question as the program advances. The absence of any approved anosmia regenerative therapy or pharmacological treatment for persistent post-viral hyposmia means that CYR-064, if it confirms efficacy in Phase III, would enter a market with no direct commercial competition. The detailed FLAVOR trial smell loss data, expected at a medical conference later in 2026, will be closely watched by otolaryngologists, neurologists, and the broader drug development community for the specifics that this topline readout did not provide. --- Spot something wrong? [Report an issue with this article](https://newsgen-prod.reframedata.com/feedback/cyr-064-phase-ii-cyrano-therapeutics-shows)