Two more canon chapters for your KIA list, Philip.

And if no neophytes could be engineered then, in time, the Chapter itself would die, as so many had in the past. The Sons of Gorgax and the Silver Stars were now no more than dusty memories, the only evidence of their existence being a record within the Index Astartes. So it was that the life of the Chapter was totally dependant upon the medicae work of the Apothecaries.
Conquest of Armageddon (novel), p44