definiens: means any chemical ( includingany Cytotoxic Compounds ), biological ( including any Antibodies ) and other tangibleresearch materials Controlled by [COMPANY] and provided by [COMPANY] to CytomXunder this Agreement . Subject to the last sentence of this definition, any mutant, derivative, progeny or improvement of [COMPANY] Proprietary Materials shall beconsidered to be [COMPANY] Proprietary Materials . Without limiting the generality of theforegoing, any [ * * * ] furnished by [COMPANY] to CytomX or any of its Affiliates, Sublicensees or Permitted Third Party Service Providers, including, without limitation anysamples, cultures or cell banks derived directly or indirectly from any [ * * * ], derivative, [ * * * ] or improvement thereof ( collectively, [ * * * ] ), shall be deemed to be [COMPANY] ProprietaryMaterials and included within the Licensed Know‑How . Without prejudice to any ofImmunoGen ’s intellectual property rights in and to MAY Compounds, any tangible MAYCompounds manufactured by or for CytomX or any of its Affiliates, Sublicensees orPermitted Third Party Service Providers using the [ * * * ] as a precursor in connection withthe Development, Manufacture, use and Commercialization of Licensed Products shallnot be deemed to be [COMPANY] Proprietary Materials for purposes of this Agreement