Independent analysis puts a QYB survodutide lot at 95.9%, against 94.3% on the certificate

A peptide content determination commissioned by the Journal on a 10 mg survodutide vial from QYB has returned 89% of the labelled mass. Chromatographic purity on the same vial was above 95.9%. The two numbers measure different things and only one of them was on the certificate.

The Journal purchased 200 vials from the same lot and had 12 of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.

Reported figures across the set were: highest 95.9%, lowest 94.3%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 12 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Discrepancies of one to two percentage points between a supplier’s figure and an independent determination are common and usually explicable: a faster gradient resolves fewer impurities, a higher integration threshold discards more small peaks, and a wider solvent-front exclusion window removes early-eluting fragments from the calculation altogether. None of that is misconduct. All of it is invisible unless the method is disclosed.

"The useful thing in that report is not the percentage, it is the system suitability data," said Lorcan Feeney, analytical services director at an independent laboratory. "It is the only part that tells you whether the percentage means anything."

QYB’s dossier has been updated with this determination and with the date of the request for comment. The dossier’s "what we could not verify" box records the questions still outstanding.