Assignment and Assumption dated as of August 4, 2020, by and among Athenex, Inc, as the borrower, Sagard Healthcare Royalty Partners, LP, OPB SHRP Co-Invest Credit Limited and SIMCOE SHRP Co-Invest Credit Ltd., as assignees, and the affiliates of Oaktree Capital Management, L.P. party thereto as assignors, and the other assignees party thereto

Exhibit 10.4

ASSIGNMENT AND ASSUMPTION

This Assignment and Assumption (this “Assignment and Assumption”) is dated as of the Effective Date set forth below and is entered into by and between Oaktree-TCDRS Strategic Credit, LLC; Exelon Strategic Credit Holdings LLC; Oaktree-NGP Strategic Credit, LLC; Oaktree-Minn Strategic Credit, LLC; Oaktree-Forrest Multi-Strategy, LLC - Series A; Oaktree-TBMR Strategic Credit Fund C, LLC; Oaktree-TBMR Strategic Credit Fund F, LLC; Oaktree-TBMR Strategic Credit Fund G, LLC; Oaktree-TSE 16 Strategic Credit, LLC; INPRS Strategic Credit Holdings, LLC; Oaktree Gilead Investment Fund AIF (Delaware), L.P.; Oaktree Huntington-GCF Investment Fund (Direct Lending AIF), L.P.; Oaktree Strategic Income II, Inc.; Oaktree Specialty Lending Corporation; and Oaktree Strategic Income Corporation (each, an “Assignor” and collectively, the “Assignors”) and Sagard Healthcare Royalty Partners, LP; OPB SHRP Co-Invest Credit Limited; and Simcoe SHRP Co-Invest Credit Ltd. (each, an “Assignee” and collectively, the “Assignees”). Capitalized terms used herein and not otherwise defined herein are used herein as defined in the Credit Agreement and Guaranty, dated as of June 19, 2020 (as amended or otherwise modified from time to time, the “Credit Agreement”), among Athenex, Inc., a Delaware corporation (the “Borrower”), the Subsidiary Guarantors from time to time party thereto, the lenders from time to time party thereto (the “Lenders”) and Oaktree Fund Administration, LLC, as administrative agent for the Lenders (in such capacity, together with its successors and assigns, the “Administrative Agent”), receipt of a copy of which is hereby acknowledged by the Assignee. The Standard Terms and Conditions set forth in Annex 1 attached hereto are hereby agreed to and incorporated herein by reference and made a part of this Assignment and Assumption as if set forth herein in full.

For an agreed consideration, the Assignors hereby irrevocably sell and assign to the Assignees, and the Assignees hereby irrevocably purchase and assume from the Assignors, subject to and in accordance with the Standard Terms and Conditions and the Credit Agreement, as of the Effective Date inserted by the Administrative Agent as contemplated below (i) all of the Assignors’ rights and obligations in their capacity as Lenders under the Credit Agreement and any other documents or instruments delivered pursuant thereto to the extent related to the amount and percentage interest identified below of all of such outstanding rights and obligations of the Assignors under the Credit Agreement and (ii) to the extent permitted to be assigned under applicable law, all claims, suits, causes of action and any other right of the Assignors (in their capacity as Lenders) against any Person, whether known or unknown, arising under or in connection with the Credit Agreement, any other documents or instruments delivered pursuant thereto or the loan transactions governed thereby or in any way based on or related to any of the foregoing, including, but not limited to, contract claims, tort claims, malpractice claims, statutory claims and all other claims at law or in equity related to the rights and obligations sold and assigned pursuant to clause (i) above (the rights and obligations sold and assigned by the Assignors to the Assignees pursuant to clauses (i) and (ii) above being referred to herein collectively as the “Assigned Interest”). Such sale and assignment is without recourse to the Assignors and, except as expressly provided in this Assignment and Assumption, without representation or warranty by the Assignors.

The Borrower and the Administrative Agent agree that, for purposes of the Credit Agreement, an Affiliate of OPB SHRP Co-Invest Credit Limited and Simcoe SHRP Co-Invest Credit Ltd. shall be deemed to include (i) any Person in which Workplace Safety and Insurance Board in any capacity (“WSIB”), Trustees of the Workplace Safety and Insurance Board Employees’ Pension Plan Trust (the “Trustees”) or the Ontario Pension Board (“OPB”) holds a direct or indirect majority beneficial ownership interest such as a trust of which WSIB or an Affiliate of WSIB is the sole beneficiary, (ii) any other Person through which the assets of only the Workplace Safety and Insurance Board Employees’ Pension Plan, Workplace Safety and Insurance Board Insurance Fund and/or the Workplace Safety and Insurance Board Loss of Retirement Income Fund are, directly or indirectly, invested, (iii) WSIB, the Trustees or OPB, (iv) an Affiliate of WSIB, the Trustees or OPB, (v) any member of IMCO (as contemplated by the Investment

Management Corporation of Ontario Act, 2015) (an “IMCO Client”), (vi) any Affiliate of any IMCO Client, and (vii) any Person in which one or more IMCO Clients holds a direct or indirect majority beneficial ownership interest (including, without limiting the generality of the foregoing, any trust or limited partnership of which one or more IMCO Clients or Affiliates of IMCO Clients are directly or indirectly invested); provided such Person’s assets are managed directly or indirectly by IMCO on behalf of such IMCO Clients.

Each party hereto agrees that no past, present or future director, officer, employee, incorporator, member, partner, stockholder, Affiliate, agent, attorney or representative of the Assignors shall have any liability (whether in contract or in tort) to the Assignees arising under, in connection with or related to this Assignment and Assumption and the Assigned Interests including, without limitation, any alleged non-disclosure or misrepresentations made by any such Persons.

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Effective Date:August 4, 2020

The terms set forth in this Assignment and Assumption are hereby agreed to:

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Consented to:

Athenex, Inc.

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ANNEX 1

STANDARD TERMS AND CONDITIONS

1.Representations and Warranties.

1.1Assignor. The Assignor (a) represents and warrants that (i) it is the legal and beneficial owner of the Assigned Interest, (ii) the Assigned Interest is free and clear of any lien, encumbrance or other adverse claim and (iii) it has full power and authority, and has taken all action necessary, to execute and deliver this Assignment and Assumption and to consummate the transactions contemplated hereby; and (b) assumes no responsibility with respect to (i) any statements, warranties or representations made in or in connection with the Credit Agreement or any other Loan Document, (ii) the execution, legality, validity, enforceability, genuineness, sufficiency or value of the Loan Documents or any collateral thereunder, (iii) the financial condition of the Borrower, any of its Subsidiaries or Affiliates or any other Person obligated in respect of any Loan Document or (iv) the performance or observance by the Borrower, any of its Subsidiaries or Affiliates or other Person of any of their respective obligations under any Loan Document.

1.2Assignee. The Assignee (a) represents and warrants that (i) it has full power and authority, and has taken all action necessary, to execute and deliver this Assignment and Assumption and to consummate the transactions contemplated hereby and to become a Lender under the Credit Agreement, (ii) it is an Eligible Transferee, and it satisfies the requirements, if any, specified in the Credit Agreement that are required to be satisfied by it in order to acquire the Assigned Interest and become a Lender, (iii) from and after the Effective Date, it shall be bound by the provisions of the Credit Agreement as a Lender thereunder and, to the extent of the Assigned Interest, shall have the obligations of a Lender thereunder, (iv) it is sophisticated with respect to decisions to acquire assets of the type represented by the Assigned Interest and either it, or the Person exercising discretion in making its decision to acquire the Assigned Interest, is experienced in acquiring assets of such type, (v) it has received a copy of the Credit Agreement, together with copies of the most recent financial statements delivered pursuant to Sections 8.01(a) and (b) thereof, as applicable, and such other documents and information as it has deemed appropriate to make its own credit analysis and decision to enter into this Assignment and Assumption and to purchase the Assigned Interest on the basis of which it has made such analysis and decision independently and without reliance on the Administrative Agent or any other Lender and (vi) attached to the Assignment and Assumption is any documentation required to be delivered by it pursuant to the terms of the Credit Agreement, duly completed and executed by the Assignee; and (b) agrees that (i) it will, independently and without reliance on the Administrative Agent, the Assignor or any other Lender, and based on such documents and information as it shall deem appropriate at the time, continue to make its own credit decisions in taking or not taking action under the Loan Documents, and (ii) it will perform in accordance with their terms all of the obligations which by the terms of the Loan Documents are required to be performed by it as a Lender.

2.Payments. From and after the Effective Date, the Administrative Agent shall make all payments in respect of the Assigned Interest (including payments of principal, interest, fees and other amounts) to the Assignee whether such amounts have accrued prior to, on or after the Effective Date. The Assignor and the Assignee shall make all appropriate adjustments in payments by the Administrative Agent for periods prior to the Effective Date or with respect to the making of this assignment directly between themselves.

3.General Provisions. This Assignment and Assumption shall be binding upon, and inure to the benefit of, the parties hereto and their respective successors and assigns. This Assignment and Assumption may be executed in any number of counterparts, which together shall constitute one instrument. Delivery of an executed counterpart of a signature page of this Assignment and Assumption by facsimile or other electronic transmission (PDF format) shall be effective as delivery of a manually executed counterpart of this Assignment and Assumption. This Assignment and Assumption shall be governed by, and construed in accordance with, the law of the State of New York.