Back Spike (world)/secret
In the 690s, Spike Society scientists managed to synthesize anagathics following a formula officially "contributed by an eccentric, anonymous inventor". Only the highest levels of Spike Society intelligence officers were cleared to know this inventor was actually Tiji of the Tijian Khaganate, who contributed the formula because he wanted anagathics available to but not manufactured in the Tijian Khaganate. They assume it was his invention; not a one knows where he really got the formula and infrastructure recipes from. A number of them have correctly guessed that Tiji is a series of clones, and that wider availability of anagathics in the Tijian Khaganate might interfere with his ability to continue ruling as a series of clones instead of a single never-aging individual.
Regardless of the origin of this knowledge, manufacturing capability was established on Back Spike, well hidden from outsiders. There it remained until the Empress Wave destroyed it via psionically-driven plant based wreckage, the same way the Empress Wave wrecked many other buildings and starports. The Spike Society's surviving leadership had enough reserve supply to last for a while, but rebuilding Back Spike was a personal priority so as to reestablish the infrastructure needed for the anagathics factory, as well as the factory itself. This goal was met well before 1097, but by the time the factory was back up and running, the public had become used to the story that Back Spike was being rebuilt for its own purposes. It was convenient to maintain this fiction until the public tired of it in 1097.