Flotufolastat F 18
A fluorine-18 PSMA scan agent built to leave less radioactivity in the bladder
Flotufolastat F 18, developed as 18F-rhPSMA-7.3, is a radioactive imaging agent that binds PSMA on prostate cancer cells so that a PET scan can show where the cancer is. It was approved in the US as Posluma in 2023. It is a hospital diagnostic, given once by injection before a scan, and nobody can buy it or use it for anything else.
Manufacturer's recommended dosing (FDA label): 296 MBq (8 mCi), Single injection, Intravenous bolus, at most 5 mL undiluted Details ↓
Recommended Dosing
Manufacturer's recommended dosing (FDA label)
From the prescribing information. Other doses studied, if any, are in the full dosing data below.
What is it?
Radioligand scans pair a molecule that recognises a target in the body with a radioactive atom a scanner can see. For prostate cancer the usual target is prostate-specific membrane antigen (PSMA), a surface protein that most prostate tumours carry in large amounts. After a small injection, the agent spreads through the blood, sticks where PSMA is plentiful and is cleared from everywhere else; the positron emission tomography (PET) camera then records where the radioactivity has collected, and a CT scan taken in the same session shows the anatomy underneath. The amounts of drug are tiny and the agent does nothing therapeutic: it is a way of seeing.
Flotufolastat F 18 is a radiohybrid agent. The part of it that binds PSMA carries two handles: a silicon-fluoride group that holds the radioactive fluorine-18, and a DOTAGA chelator that holds an atom of ordinary, non-radioactive gallium. The design lets one molecule be labelled with either fluorine-18 or a radioactive metal. A US trial team describes it as the FDA-approved PSMA agent with the least radioactivity passing into urine. That matters because the bladder sits next to the prostate, and a bright bladder can hide a small recurrence. On the label, only about 7% of the injected radioactivity reaches the urine in the first two hours.
FDA approved it as Posluma in May 2023 for the same two groups as the other PSMA PET agents: men with suspected spread who are candidates for a first curative treatment, and men with a rising PSA after treatment. It is not in the European Medicines Agency's register of authorised medicines. Like every PET radiopharmaceutical, it is produced on the day, expires 10 hours after manufacture and is given only by licensed nuclear medicine staff. There is no form of it that a person could buy, and it has no use outside a scan.
Two phase 3 trials supported the approval. In LIGHTHOUSE, 352 newly diagnosed men were scanned and 296 then had surgery: the scan correctly cleared 93% to 97% of the men whose pelvic nodes were free of cancer, but it found only 23% to 30% of the men whose nodes held cancer, so the sensitivity goal was missed. In SPOTLIGHT, 389 men with suspected recurrence, the scan was positive in 83%, and the share of men with at least one lesion confirmed by biopsy or follow-up imaging (51% to 54%) met its target; the region-level positive predictive value did not. In the 171 SPOTLIGHT men whose standard imaging had been negative, 95% had a positive scan and 64% had a confirmed true-positive lesion.
Studies since then fill in the picture. In a German series of 242 men with recurrence after surgery, it found disease in 62% even at PSA between 0.2 and 0.5 ng/mL, and a simulated tumour board changed treatment in 63%. When men with a negative first scan were scanned again later, 57% of 101 had a positive second scan, more often when PSA had risen. In a small US trial, a 20 mg injection of the diuretic furosemide with the tracer cut bladder activity to about a third and raised detection of recurrence in the prostate bed from 60% to 85%. A 2026 comparison in the same 55 men found much lower bladder activity than with piflufolastat and a higher positive rate (45% against 27%).
The label warns about misreading. Uptake is not unique to prostate cancer, and in the recurrence trial readers disagreed most often about the prostate and prostate bed, so the label suggests a second opinion or biopsy when a decision rests only on uptake there or on a borderline spot. A reproducibility study still found that readers agreed with each other in at least 95% of newly diagnosed and 75% of recurrent cases. In six healthy volunteers, the effective radiation dose was 0.0141 mSv per MBq, about 4 mSv for the 296 MBq label activity, and one mild headache was the only possibly related adverse event.
Mechanism of Action
Flotufolastat F 18 binds prostate-specific membrane antigen and carries fluorine-18, so cancer that carries PSMA shows on a PET scan.
PSMA binding
A high-affinity motif that binds PSMA attaches to prostate cancer cells that display the protein.
Radiohybrid design
Fluorine-18 sits on a silicon-fluoride acceptor; a DOTAGA chelator holds non-radioactive gallium (label section 11).
Distribution and clearance
It goes to liver (15.8% of the dose), heart blood pool (7.4%) and kidneys (3.2%); about 7% reaches the urine in 2 hours and 15% by 4.5 hours (label 12.3).
Published Research
The studies behind flotufolastat F 18 (18F-rhPSMA-7.3), read from their PubMed abstracts. Studies of the related isomer mixture 18F-rhPSMA-7 are left out, because it is a different product.
LIGHTHOUSE: staging before surgery
In 352 newly diagnosed men scanned 50 to 70 minutes after 296 MBq, 296 of whom had node dissection, sensitivity for pelvic node metastases was 23% to 30% across three readers (missing its threshold) and specificity 93% to 97% (meeting it); distant lesions were reported in 16% to 28%, and no serious adverse events occurred.
SPOTLIGHT: suspected recurrence
Among 389 men with an evaluable scan the detection rate was 83%; in 366 with a standard of truth, the verified detection rate (51% to 54%) met its threshold but region-level positive predictive value (46% to 60%) did not. In the histopathology subset both were above threshold, at 81% and 72%.
SPOTLIGHT: men with negative standard imaging
In 171 men whose conventional imaging had been negative, 95% had a positive scan and 64% had at least one true-positive lesion confirmed by biopsy or follow-up imaging; after prostatectomy, confirmed lesions were mostly in pelvic nodes and distant sites.
African American men in SPOTLIGHT
The 61 African American participants (17% of the trial) had a detection rate of 93% and a verified detection rate of 64%, similar to or slightly higher than other participants.
Do readers agree?
Across 741 scans from both phase 3 trials, pairs of masked readers agreed in at least 95% of newly diagnosed and 75% of recurrent cases, and readers agreed with their own earlier reads in at least 86%.
First in humans: safety and dosimetry
Six healthy volunteers received about 220 MBq; one mild headache was possibly related, the effective dose was 0.0141 mSv per MBq, the adrenals and kidneys received the most, and about 7% of the activity was in the urine by 111 minutes.
Phase 1 in prostate cancer
In ten men with localised, hormone-sensitive or castration-resistant cancer, the scan found the primary tumour in all three localised cases and node or bone lesions in all seven metastatic patients, including some not seen on standard imaging.
Primary staging against surgery
In 83 men who had prostatectomy with node dissection, patient-level sensitivity and specificity for pelvic node metastases were 66.7% and 96.6%, against 37.5% and 91.5% for conventional cross-sectional imaging, with better agreement between readers.
Recurrence before salvage treatment
In 242 men with biochemical recurrence after prostatectomy, 72.7% had positive findings, from 61.8% at PSA 0.2 to under 0.5 ng/mL to 95.7% at 2 ng/mL or more; a simulated tumour board changed treatment in 63.2%.
A second scan after a negative one
Of 101 men with suspected recurrence after prostatectomy and a negative first scan, 57% had a positive second scan; positivity was more likely with PSA above 0.82 ng/mL, a doubling of PSA, or a PSA doubling time of 17 months or less.
Furosemide to quiet the bladder
Twenty men had two scans, one with 20 mg of intravenous furosemide; median bladder SUVmax fell from 13.35 to 4.20 and prostate-bed recurrence detection rose from 60% to 85%, with no difference in other regions.
Normal-organ uptake
In 546 scans from LIGHTHOUSE and SPOTLIGHT, liver uptake was consistent (mean SUVmean 6.7) while bladder uptake varied widely (median 10.6); bladder uptake was lower than reported for gallium-68 PSMA-11 and 18F-DCFPyL.
Against piflufolastat in the same men
In 55 men with PSA of 0.5 ng/mL or less after prostatectomy, median bladder activity was 10.9 with flotufolastat against 29.0 with piflufolastat, and patient-level detection was 45.5% against 27.3%.
First approval summary
Summarises the development of flotufolastat F 18 by Blue Earth Diagnostics, part of Bracco Imaging, up to its first US approval in May 2023 for PSMA PET before definitive therapy or with suspected recurrence.
Dosing Data
Flotufolastat F 18 is a single intravenous diagnostic dose, measured in radioactivity and given by nuclear medicine staff; the PET scan starts about an hour later.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
The approved product, as its label describes it:
- Posluma (flotufolastat f-18 injection): POSLUMA injection is supplied as a clear, colorless solution in a multiple-dose glass vial containing 296 MBq/mL to 5,846 MBq/mL (8 mCi/mL to 158 mCi/mL) as flotufolastat F 18 gallium in approximately 25 mL at end of synthesis.
Source: Posluma (flotufolastat f-18 injection) label, How Supplied (DailyMed version 11, effective July 25, 2026).
Mixing a vial: a worked example
Nothing to mix at home, and no syringe units to work out: Flotufolastat F 18 is a radioactive drug, prepared and given in nuclear-medicine departments, and its dose is an amount of radioactivity (MBq or GBq), not a weight.
This page's dosing note: “Flotufolastat F 18 is dosed by radioactivity, 296 MBq, measured by nuclear medicine staff against the time since production; no reconstitution maths applies.”
Its label says: “Radiopharmaceuticals should be used by or under the control of physicians who are qualified by specific training and experience in the safe use and handling of radionuclides, and whose experience and training have been approved by the appropriate governmental agency authorized to license the use of radionuclides.”
Source: this page's own note in Dosing Data below; Posluma (flotufolastat f-18 injection) label, section 2 (DailyMed version 11, effective July 25, 2026); the amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: the label on file for Flotufolastat F 18 (Posluma (flotufolastat f-18 injection) label, sections 16 and 2 (DailyMed version 11, effective July 25, 2026)) has no storage sentence we could read. It is a radioactive drug held by the nuclear-medicine department that prepares and gives it (see the part above); the home rules for a mixed vial in the mixing guide do not apply to it.
How it is taken
As the approved label gives it: Intravenous bolus, at most 5 mL undiluted (Single injection; Label: PSMA PET in men with prostate cancer (Posluma)).
Source: Manufacturer's recommended dosing (FDA label): the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: not established by a measurement cited on this entry.
How long the doses were given: Label: PSMA PET in men with prostate cancer (Posluma): Imaging about 60 minutes after injection, mid-thigh to skull base.
When effects appear: unknown; no source on this page gives a time to effect for Flotufolastat F 18. Results reported in the studies are under Published Research.
Source: Manufacturer's recommended dosing (FDA label), the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: One mild headache, possibly related, among six healthy volunteers; No serious adverse events in the LIGHTHOUSE trial; no significant safety concerns in SPOTLIGHT; Radiation exposure: an effective dose of 0.0141 mSv per MBq in healthy volunteers. Full list and cautions ↓
When to stop or get help: unknown; the label's warnings summary we read gives no rule for stopping Flotufolastat F 18. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the studies above”).
Interactions
- androgen deprivation therapy and other therapies targeting the androgen pathway: can change flotufolastat F 18 uptake in prostate cancer; the effect on PET performance has not been established
Every peptide's record, with its source: the interaction matrix.
Source: Posluma (flotufolastat F 18) injection, US prescribing information, section 7. DailyMed set 907ac4a4, version 11, effective July 25, 2026, read October 28, 2026.
Checking what you bought
Unknown: no published independent test of Flotufolastat F 18 products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder; it checks the measured mass against Flotufolastat F 18's expected mass, 1,471.6 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: FDA Approved (FDA-approved: Posluma, NDA 216023 (Blue Earth Diagnostics), approved May 25, 2023 (Drugs@FDA via openFDA, read October 29, 2026). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the studies above.
Contraindications & Cautions
From the Posluma US prescribing information (DailyMed set 907ac4a4, version 11, effective July 25, 2026), sections 4, 5 and 7.
Legal Status
Flotufolastat F 18 is an approved prescription diagnostic drug in the US only, given in nuclear medicine departments.
Frequently Asked Questions
?What is a radioligand scan?
An imaging test in which a small amount of a molecule that binds one target, here PSMA on prostate cancer cells, is injected with a radioactive label attached. A PET scanner then shows where the molecule has collected. It is a diagnostic, not a treatment.
?Can I buy flotufolastat?
No. It is a radioactive prescription diagnostic made on the day of use, it expires within hours, and only licensed nuclear medicine staff can give it. It has no use outside a scan.
?What does radiohybrid mean?
The molecule carries both a silicon-fluoride group, which holds radioactive fluorine-18, and a chelator holding a metal, here non-radioactive gallium. The same design can be labelled with either kind of isotope.
?Why does lower bladder activity matter?
The bladder sits beside the prostate. When it fills with radioactive urine it can hide a small recurrence nearby. With flotufolastat about 7% of the dose reaches the urine in the first two hours.
?How is the scan done?
Patients drink water beforehand, receive one injection of 296 MBq into a vein, empty the bladder, and are scanned about an hour later from mid-thigh to the base of the skull. The scan takes about 20 minutes.
References
- [fda-pi] Posluma (flotufolastat F 18) injection, US prescribing information, sections 1, 2, 4, 5, 7, 11 and 12.3 (Blue Earth Diagnostics; DailyMed set 907ac4a4, version 11, effective July 25, 2026; read October 29, 2026).
- [other] PubChem CID 149063248, Flotufolastat: formula C63H99FN12O25Si, molecular weight 1471.6. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/149063248
- [fda] US FDA, Drugs@FDA (openFDA): POSLUMA, NDA 216023, original approval May 25, 2023; marketing status prescription. Read October 29, 2026.
- [other] European Medicines Agency, medicines list (downloaded October 3, 2026; searched October 29, 2026): no record for flotufolastat.
- [pubmed] Surasi DS, et al. "Diagnostic Performance and Safety of Positron Emission Tomography with (18)F-rhPSMA-7.3 in Patients with Newly Diagnosed Unfavourable Intermediate- to Very-high-risk Prostate Cancer: Results from a Phase 3, Prospective, Multicentre Study (LIGHTHOUSE)." Eur Urol, 2023;84(4):361-370. PMID: 37414702.
- [pubmed] Jani AB, et al. "Diagnostic Performance and Safety of (18)F-rhPSMA-7.3 Positron Emission Tomography in Men With Suspected Prostate Cancer Recurrence: Results From a Phase 3, Prospective, Multicenter Study (SPOTLIGHT)." J Urol, 2023;210(2):299-311. PMID: 37126069.
- [clinical-trial] Fleming MT, et al. "True-Positive (18)F-Flotufolastat Lesions in Patients with Prostate Cancer Recurrence with Baseline-Negative Conventional Imaging: Results from the Prospective, Phase 3, Multicenter SPOTLIGHT Study." J Nucl Med, 2024;65(7):1080-1086. PMID: 38782456.
- [pubmed] Rais-Bahrami S, et al. "(18)F-Flotufolastat Positron Emission Tomography in African American Patients With Suspected Prostate Cancer Recurrence: Findings From the Phase 3 SPOTLIGHT Study." Adv Radiat Oncol, 2024;9(9):101571. PMID: 39188996.
- [clinical-trial] Kuo PH, et al. "Interreader and Intrareader Reproducibility of (18)F-Flotufolastat Image Interpretation in Patients with Newly Diagnosed or Recurrent Prostate Cancer: Data from Two Phase 3 Prospective Multicenter Studies." J Nucl Med, 2024;65(8):1239-1243. PMID: 38871390.
- [clinical-trial] Tolvanen T, et al. "Safety, Biodistribution, and Radiation Dosimetry of (18)F-rhPSMA-7.3 in Healthy Adult Volunteers." J Nucl Med, 2021;62(5):679-684. PMID: 33067338.
- [clinical-trial] Malaspina S, et al. "Uptake of (18)F-rhPSMA-7.3 in Positron Emission Tomography Imaging of Prostate Cancer: A Phase 1 Proof-of-Concept Study." Cancer Biother Radiopharm, 2022;37(3):205-213. PMID: 34962139.
- [pubmed] Langbein T, et al. "Utility of (18)F-rhPSMA-7.3 PET for Imaging of Primary Prostate Cancer and Preoperative Efficacy in N-Staging of Unfavorable Intermediate- to Very High-Risk Patients Validated by Histopathology." J Nucl Med, 2022;63(9):1334-1342. PMID: 34992154.
- [pubmed] Rauscher I, et al. "Detection Efficacy of (18)F-rhPSMA-7.3 PET/CT and Impact on Management in Patients with Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy and Before Potential Salvage Treatment." J Nucl Med, 2021;62(12):1719-1726. PMID: 33712531.
- [pubmed] Kirchhoff S, et al. "Value of a repeat (18)F-flotufolastat PET scan following a negative scan in patients with suspected biochemical recurrence of prostate cancer after radical prostatectomy." Eur J Nucl Med Mol Imaging, 2026;53(8):4862-4872. PMID: 41721835.
- [clinical-trial] Lawal IO, et al. "Diuresis During (18)F-Flotufolastat (rhPSMA-7.3) PET/CT Improves Recurrence Detection After Prostatectomy: A Prospective Phase II Trial." J Nucl Med, 2025;66(2):230-237. PMID: 39848765.
- [pubmed] Penny R, et al. "Normal-organ distribution of PSMA-targeting PET radiopharmaceutical (18)F-flotufolastat: a post hoc analysis of the LIGHTHOUSE and SPOTLIGHT studies." Am J Nucl Med Mol Imaging, 2024;14(5):337-344. PMID: 39583908.
- [clinical-trial] Nordquist LT, et al. "An intra-patient contemporaneous comparison of (18)F-piflufolastat and (18)F-flotufolastat urinary radioactivity and pelvic region detection rates in men with low PSA biochemical recurrence of prostate cancer after radical prostatectomy." Eur J Nucl Med Mol Imaging, 2026;53(6):3529-3541. PMID: 41729277.
- [review] Heo YA. "Flotufolastat F 18: Diagnostic First Approval." Mol Diagn Ther, 2023;27(5):631-636. PMID: 37439946.
Sources & Citations
Studies were read from their PubMed abstracts; the Posluma label from DailyMed and the approval from Drugs@FDA, read October 29, 2026. The stub's searches (October 28, 2026) found 34 PubMed records for flotufolastat or rhPSMA-7.3, 19 ClinicalTrials.gov studies, 1 Drugs@FDA record and none at the EMA.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.