The short version
5 companies supply this market — a reasonable cushion if one runs into trouble. The generic price has fallen 48% in a year, to $95.02 per unit — and generics that get this cheap tend to get abandoned rather than defended. The brand (Dificid) runs $248.47 per unit — 2.6× more. Put together: this looks like a healthy supply — the boring kind, which is exactly what you want.
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