VendorInvestigate result on a Xi'an cagrilintide lot lands 0.7 points below the supplier’s figure

Two laboratories analysing vials from the same cagrilintide lot have returned figures 0.7 percentage points apart. VendorInvestigate reported 98.3%; PeptideMeter reported a lower number on a shallower gradient with a tighter integration threshold. Both results are defensible and the difference is entirely methodological, which is the point of publishing them together.

Reported figures across the set were: highest 98.3%, lowest 94.9%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 21 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

The Journal purchased 2000 vials from the same lot and had 21 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.

Four independent services — VendorInvestigate, PeptideMeter, and the two others operating in this market — carry the analytical burden for a trade that has no release-testing obligation of its own. Each is paid by whoever submits the sample, which is usually the vendor. The Journal’s position is that a submitter-pays model is workable but that its incentive structure has to be stated whenever a result is quoted as verification.

"Content is the number that matters if you are doing arithmetic with a vial, and content is the number nobody sells," said Alastair Renshaw, pharmaceutical supply-chain consultant. "Purity is what you can afford. Content is what you need."

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.