SPPI—I assume [the non-inferiority delta for approval of the Rituxan biosimilar] would be based on some fraction of whatever delta there was historically between CHOP-R and CHOP.
I don’t think the NI delta for a Rituxan biosimilar from SPPI (or anyone else) will be based on NI deltas used in prior Rituxan studies; rather, it will be an arbitrary value negotiated by the sponsor and the FDA.
If the FDA is unduly demanding in the specification of NI deltas for approval of FoB’s, it will undermine the intent of the enabling legislation for FoB’s and invite the wrath of Congress, which is something the FDA probably does not want.