What it is
Piflufolastat F 18 is the active ingredient of Pylarify, a radioactive diagnostic drug. It is injected once, travels to cells that carry a protein called PSMA (prostate-specific membrane antigen), and the radioactive fluorine-18 atom it carries shows those cells on a PET scan. Most prostate cancer cells carry PSMA in large amounts, so the scan shows where the cancer is.
It is not a peptide. The label's chemical name describes a small molecule built around a urea link: 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}ureido)-pentanedioic acid, molecular weight 441.4. PubChem's record (CID 71532123) gives the formula C18H23FN4O8. It appears in this library because readers meet it alongside PSMA tracers that are described as peptide-like, such as gozetotide, and alongside true peptide tracers such as DOTATATE.
How it works
The mechanism section of the label is two sentences long: the molecule binds to cells that express PSMA, and fluorine-18 emits positrons that a PET scanner detects. The label's pharmacokinetics section adds that blood levels fall in two phases (half-lives of 0.17 and 3.47 hours), that the kidneys take up 16.5% of the injected activity within an hour, and that about half of the radioactivity leaves in the urine in the first 8 hours.
What the two trials found
The label rests on two open-label trials, each read by three blinded central readers.
| Trial | Who was scanned | What was measured | Result (range across 3 readers) |
|---|---|---|---|
| OSPREY (NCT02981368) | 252 evaluable men with high-risk cancer, before prostatectomy | Pelvic lymph-node cancer vs. surgical pathology | Sensitivity 28–39%, specificity 95–98%, PPV 72–81%, NPV 81–84% |
| CONDOR (NCT03739684) | 208 men with rising PSA after treatment; standard imaging negative or unclear | Whether positive spots matched a reference standard | Correct localisation rate 85–87% (imputed across all scanned men: 78–81%) |
What these numbers mean in plain terms. In OSPREY, about 24% of the men had cancer in their pelvic lymph nodes on pathology. When the scan was positive it was usually right, but it missed more than half of the men whose nodes were affected. In CONDOR, 59–66% of men had at least one positive spot, and in the men whose spots could be checked, most were confirmed. The correct localisation rate counts only checkable positives, so it says nothing about cancers the scan did not show.
Safety, as the label reports it
In 593 trial patients who each received one dose, the label lists headache in 13 (2%), altered taste (dysgeusia) in 10 (2%) and fatigue in 7 (1%), plus one hypersensitivity reaction. The warnings section names three risks: misreading the image (PSMA uptake also occurs in other cancers, in non-cancerous conditions and in normal tissue), hypersensitivity, and radiation exposure.
What is not established
- The label states plainly that a negative scan does not rule out prostate cancer and a positive scan does not confirm it; clinical correlation, sometimes a biopsy, is recommended.
- OSPREY did not count prostate-gland or distant findings in its primary analysis, so the trial figures above describe pelvic lymph nodes only.
- This entry does not compare piflufolastat with other PSMA tracers, such as the larger fluorine-18 agent flotufolastat F 18 (Posluma). A comparison of products is not what this library does, and the trials above did not test one against another.
Where it stands
| Question | Answer as of 2026-11-10 |
|---|---|
| Is it a peptide? | No — a urea-based small molecule (label) |
| US status | Pylarify, NDA 214793, approved 2021-05-26; Pylarify TruVu, NDA 220089, 2026-03-06 (Drugs@FDA) |
| Given by | A nuclear-medicine team, one intravenous dose before a PET/CT scan |
| Published record | 499 PubMed records; 45 tagged as clinical trials |
| Advice | None given here. Questions about a scan belong with the treating team. |
Related reading
For a true peptide tracer used in a different cancer, see the entry on DOTATATE, which binds the same somatostatin receptors that the somatostatin copy octreotide targets. A PSMA-targeted drug that treats rather than images prostate cancer is vipivotide tetraxetan (Pluvicto). The library's peptide vs. protein entry explains where the line between a peptide and other molecules is drawn.