A medical requisition form from the facility
The D'Dren Medical Facility was a Cardassian hospital in a Bajoran internment camp in the Bajor sector, one of the places Dr. Crell Moset did his research on the Fostossa virus.
Among the materials Moset requested were dermal regenerators, every strain of the Fostossa virus, and supplies of cordrazine.
The requisition forms were intercepted by the Federation, and included in starship databases thereafter. When Seven of Nine and Harry Kim were researching into claims of Crell Moset's torture in 2375, they found the requisition manifests - noting they didn't request any of the traditional antivirals needed for humane research. (VOY: "Nothing Human")
Not mentioned in dialogue, the facility is only named on the LCARS panel Seven shows The Doctor. Based on the format of the screen, it's possible this requisition went out in the year 2328.
Harry Kim mentions the information and other research they found was attained, among other ways, by Starfleet ships passing near the area. This was possibly reconnaissance during the Cardassian wars.