Exhibit
10.6


 


EXECUTION
COPY


Exhibit
E


 


WAIVER AND
TERMINATION AGREEMENT


 


THIS WAIVER AND
TERMINATION AGREEMENT (as may be amended or modified from time to time, this “Agreement”) is entered into
on November 12, 2018, by and among Fortress Biotech, Inc., a Delaware corporation (“Fortress”), Avenue Therapeutics,
Inc., a Delaware corporation (the “Company”), and InvaGen Pharmaceuticals Inc., a New York corporation (“Buyer”).


 


WHEREAS, the
Company, Madison Pharmaceuticals Inc., and Buyer have entered into that certain Stock Purchase and Merger Agreement, dated as of
the date hereof (the “SPMA”);


 


WHEREAS, in
connection with the Transactions, during the Term, Fortress has agreed to waive certain payments and benefits it may be entitled
to receive in connection with (i) its ownership of Class A Preferred Shares; (ii) the Amended and Restated Founders Agreement by
and among Fortress and the Company, dated as of September 13, 2016 (the “Founders Agreement”), attached hereto
as Exhibit A; (iii) the Management Services Agreement by and among Fortress and the Company, dated as of February 17, 2015,
as amended on May 15, 2017 (the “MSA”), attached hereto as Exhibit B; and (iv) any other Contracts between
Fortress or its Affiliates, on the one hand, and the Company, on the other hand.


 


WHEREAS, in
connection with the Transaction, Fortress has agreed that immediately prior to the Second Stage Closing, it will convert its Preferred
Shares into Common Shares, and the Founders Agreement and the MSA shall be automatically terminated.


 


NOW, THEREFORE,
in consideration of the mutual promises and covenants contained herein, and other good and valuable consideration, the receipt
and adequacy of which are hereby acknowledged, the parties agree as follows:


 


1.          Definitions.
Capitalized terms used but not defined in this Agreement shall have the respective meanings ascribed to them in the SPMA. 


 


2.          Class
A Preferred Shares.


 


		a.	Fortress hereby irrevocably waives, and such waiver shall
be deemed to occur annually prior to any distribution or payment, its right to receive (i) the annual dividend of Common Shares
equal to two and one half percent (2.5%) of the fully-diluted outstanding equity of the Company at the time of the dividend and
(ii) any fees, payments, reimbursements or other distributions not covered by clause (i), in the case of each of clauses (i) and
(ii), pursuant to the terms of the certificate of incorporation of the Company, as amended from time to time, for the period from
the date hereof to the termination of Buyer’s rights under Section 4 of the Stockholders Agreement (the “Term”).



 


		b.	In addition, Fortress agrees that immediately prior to
the Second Stage Closing, it will convert all of its Preferred Shares into Common Shares pursuant to the terms of the certificate
of incorporation of the Company, as amended from time to time.



 




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3.          Founders
Agreement. 


 





	 	a.	Fortress
hereby irrevocably waives its right to receive the following due to it under the Founders Agreement for the duration of the Term:



    


		i.	equity fees in Common Shares equal to two and one half
percent (2.5%) of the gross amount of any equity or debt financing for the Company, as set forth in Section 1.2(d) of the Founders
Agreement;



 


		ii.	a change in control fee equal to five times (5x) the
product of (i) net sales for the twelve (12) months immediately preceding a change in control of the Company and (ii) four and
one-half percent (4.5%), as set forth in Section 1.2(e) of the Founders Agreement;



 


		iii.	cash fees equal to four and one half percent (4.5%) of the Company’s annual net sales
                                                                                   of the Product, as defined in the Founders Agreement, as set forth in Section 1.2(f) of the Founders Agreement; and



 


		iv.	any fees, payments, reimbursements or other distributions not covered by clauses i, ii or iii
                                                                                  above.



 


		b.	Each of Fortress and the Company hereby agrees that the
Founders Agreement shall automatically terminate without any liability to the Company immediately prior to the Second Stage Closing
Date; no further notice or action by Fortress or Buyer shall be required to effect such termination.



 


4.          Management
Services Agreement. 


 


		a.	Fortress hereby irrevocably waives its right to receive
(i) the annual consulting fee of $0.5 million due to it under Section 3.1 of the MSA and (ii) any fees, payments, reimbursements
or other distributions not covered by clause (i), in the case of clauses (i) and (ii), for the duration of the Term; provided,
that Fortress shall continue to receive an annual payment, which as of the date hereof equals $90,000, for desk space provided
to the Company by Fortress pursuant to Section 4 of the MSA.



 


		b.	Each of Fortress and the Company hereby agrees that the
MSA shall automatically terminate without any liability to the Company immediately prior to the Second Stage Closing Date; no
further notice or action by Fortress or Buyer shall be required to effect such termination.



 




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5.            Other
Agreements. Fortress on its behalf and on behalf of any of its Affiliates hereby irrevocably waives its and its Affiliates
right to receive any fees, payments, reimbursements or other distributions from the Company not otherwise covered by this Agreement
for the duration of the Term. Each of Fortress and the Company hereby agrees that any Contract providing for any such fees, payments,
reimbursements or other distributions shall automatically terminate without any liability to the Company immediately prior to
the Second Stage Closing Date; no further notice or action by Fortress or Buyer shall be required to effect such termination.
Fortress shall not terminate any of the MSAs (as defined herein) without the Buyer’s prior written consent, and shall continue
to allow the Company to enter inter work orders under the MSAs, and the Company shall enter into such work orders, in the ordinary
course of business. To the extent that any Intellectual Property was or is developed under any of the MSAs and is owned by Fortress,
Fortress will promptly transfer such Intellectual Property, upon Buyer’s request, to the Company, at no cost. For purposes
of this Section 5, “MSAs” means the Master Services Agreement between Fortress and Axiom Real-Time Metrics
Inc. dated June 27, 2017, Master Services Agreement between Fortress and Clinical Supplies Management Holdings Inc. dated July
26, 2017, Master Services Agreement between and iCardiac Technologies Inc. dated June 13, 2017, Master Services Agreement between
Fortress and JMI Laboratories Inc. dated October 28, 2015, Master Services Agreement between Fortress and Worldwide Clinical Trials
Early Phase Services/Bioanalytical Sciences, Inc. dated November 10, 2015 and Master Services Agreement between Fortress and LabConnect,
LLC dated July 7, 2017.


 


6.            Representations
and Warranties. Each of Fortress and the Company represent and warrant to Buyer as follows (for purposes of this Section
6, each a “Representing Party”):


 


		a.	(i) It is a corporation duly organized, validly
existing and in good standing under the laws of Delaware, (ii) it is duly licensed and qualified to conduct its business
in each jurisdiction where the nature of the properties owned, leased or operated by it and the business transacted by it requires
such licensing or qualification, except where any such failures to be so qualified or licensed have not had, or are not reasonably
likely to have, a material adverse effect on its ability to perform its obligations under or to consummate the transactions contemplated
by this Agreement, and (iii) it holds all necessary corporate power and authority to own, license and operate its assets
and properties, to conduct its business, to enter into this Agreement, to perform its obligations hereunder and to consummate
the transactions contemplated hereby.



 


		b.	The execution and delivery of this Agreement by the Representing
Party and the performance by the Representing Party of its obligations hereunder have been duly authorized by all requisite action
on the part of the Representing Party, and no other actions or proceedings on the part of the Representing Party are necessary
to authorize the execution and delivery of this Agreement.



 


		c.	This Agreement has been duly executed and delivered by
the Representing Party and constitutes the valid and binding agreement
of the Representing Party, enforceable against the Representing
Party in accordance with its terms.



 




    	3



     


    

 


		d.	The execution or delivery by the Representing Party of
this Agreement or the performance by the Representing Party of its obligations under this Agreement will not (i) result in any
breach of any provision of the Representing Party’s certificate of incorporation or bylaws, (ii) result in any breach of,
require (with or without notice or lapse of time or both) any payment, consent or notice or constitute a default (or give rise
to any right of purchase, termination, amendment, acceleration or cancellation) under any Contract or order or judgment to which
the Representing Party is a party or by which it or its assets are bound, (iii) result in the creation of an Encumbrance, or (iv)
violate any applicable Legal Requirement, other than, in the case of clauses (ii) through (iv), such breaches, defaults or violations
that have not had, or are not reasonably likely to have, a material adverse effect on the ability of the Representing Party to
perform its obligations under or to consummate the transactions contemplated by this Agreement.



 


7.          Termination.
This Agreement shall automatically terminate without force and effect upon termination of Buyer’s rights under Section
4 of the Stockholders Agreement; provided that any breach hereof prior to such termination shall survive such termination.
Notwithstanding the preceding sentence, Section 8 shall survive any termination of this Agreement.


 


8.          Miscellaneous. 


 


		a.	Entire Agreement. This Agreement, together with
all other documents referred to herein, constitutes the entire agreement between the parties hereto with respect to the subject
matter of this Agreement and supersedes any and all prior agreements, negotiations, correspondence, undertakings, understandings
and communications of the parties hereto with respect to the subject matter of this Agreement.



 


		b.	Transaction Costs. Except as otherwise provided
herein, the parties to this Agreement will pay their own costs and expenses (including legal, accounting and other fees) relating
to this Agreement.



 


		c.	Modifications. Any amendment or modification to
this Agreement, including this undertaking itself, shall only be valid if effected by an instrument or instruments in writing
and shall be effective against each of the parties hereto that has signed such instrument or instruments. The parties agree that
they jointly negotiated and prepared this Agreement and that this Agreement will not be construed against any party on the grounds
that such party prepared or drafted the same.



 


		d.	Notices. Notices will be deemed to have been received
(a) upon receipt of a registered letter, (b) three Business Days following proper deposit with an internationally recognized express
overnight delivery service, or (c) in the case of transmission by email, as of the date so transmitted (or if so transmitted after
normal business hours at the place of the recipient, on the Business Day following such transmission):



 




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If to the Company:


 


Avenue Therapeutics,
Inc.


2 Gansevoort
Street, 9th Floor


New York,
NY 10014


Attn: Dr.
Lucy Lu, M.D.


Email: llu@avenuetx.com


 


With a copy
(which shall not constitute notice) to:


 


Alston &
Bird LLP


90 Park Avenue,
12th Floor


New York,
NY 10016


Attn: Mark
F. McElreath


Email: mark.mcelreath@alston.com


 


If to Fortress:


 


Fortress
Biotech, Inc.


2 Gansevoort
Street, 9th Floor


New York,
NY 10014


Attn: Dr.
Lindsay Rosenwald, M.D.


Email: lrosenwald@fortressbiotech.com


 


With a copy
(which shall not constitute notice) to:


 


Fortress
Biotech, Inc.


2 Gansevoort
Street, 9th Floor


New York,
NY 10014


Attn: Samuel
W. Berry, Esq.


Email: sberry@fortressbiotech.com


 


If to Buyer:


 


InvaGen Pharmaceuticals
Inc.


Site B, 7
Oser Ave.


Hauppauge,
NY 11788


c/o


A.S. Kumar,
Esq.


Global General
Counsel


Cipla Ltd.


Cipla House,
Peninsula Business Park,


Ganapatrao
Kadam Marg, Lower Parel West,


Mumbai, Maharashtra
400013, India


Email:
as.kumar@cipla.com and cosecretary@cipla.com


 




    	5



     


    

 


With a copy
(which shall not constitute notice) to:


 


InvaGen Pharmaceuticals
Inc.


Site B, 7
Oser Ave.


Hauppauge,
NY 11788


c/o


Nishant Saxena


Global Chief
Strategy Officer


Cipla Ltd.


Cipla House,
Peninsula Business Park,


Ganapatrao
Kadam Marg, Lower Parel West,


Mumbai, Maharashtra
400013, India


Email: nishant.saxena@cipla.com


 


With a copy
(which shall not constitute notice) to:


 


Hughes Hubbard
& Reed LLP


One Battery
Park Plaza


New York,
NY 10004-1482


Attn: Kenneth
A. Lefkowitz


Email: ken.lefkowitz@hugheshubbard.com


 


or to such other address as
may be hereafter communicated in writing by the parties in a notice given in accordance with this Section 8(d), which address
shall then apply to the respective notice provisions of the SPMA and all other Ancillary Agreements.


 


		e.	Public Announcements.
Except as required by Legal Requirements or by the requirements of any stock exchange on which the securities of a party hereto
or any of its Affiliates are listed, no party to this Agreement will make, or cause to be made, any press release or public announcement
in respect of this Agreement or the transactions contemplated hereby or otherwise communicate with any news media with respect
to the foregoing without prior notification to the other parties, and the parties to this Agreement will consult with each other
and cooperate as to the form, timing and contents of any such press release, public announcement or disclosure.



 


		f.	Severability. Each provision of this Agreement
will be interpreted in such manner as to be effective and valid under applicable Legal Requirements, but if any provision of this
Agreement is found to be unenforceable or invalid under applicable Legal Requirements, such provision will be ineffective only
to the extent of such unenforceability or invalidity, and the parties will negotiate in good faith to modify this Agreement so
that the unenforceable or invalid provision is replaced by such valid and enforceable provision which the parties consider, in
good faith, to match as closely as possible the invalid or unenforceable provision and to achieve the same or a similar economic
effect and to give effect to the parties’ original intent. The remaining provisions of this Agreement will continue to be
binding and in full force and effect.



 




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		g.	Assignment. No party hereto may assign, in whole
or in part, or delegate all or any part of its rights, interests or obligations under this Agreement without the prior written
consent of the other party. Any assignment or delegation made without such consent will be void. Notwithstanding the foregoing,
Buyer shall be entitled to (a) assign its rights under this Agreement to any one of its Affiliates, and (b) assign any or all
of its rights and obligations under this Agreement (in whole or in part) as collateral security in a financing transaction.



 


		h.	Governing Law. This Agreement and any claims or
causes of action pursuant to it will be governed by and construed in accordance with the laws of the State of Delaware, without
regard for its principles of conflict of laws.



 





		i.	Specific Performance. Each party acknowledges
and agrees that the other party would be irreparably damaged if the provisions of this Agreement are not performed in accordance
with their terms and that any breach of this Agreement and the non-consummation of the transactions contemplated hereby by either
party could not be adequately compensated in all cases by monetary damages alone. Accordingly, in addition to any remedy to which
such other party may be entitled under Section 8(j), provisional measures and injunctive relief necessary to protect the
possibility of each party to seek specific performance from the other from the tribunal referred to in Section 8(j) can
be sought from any court of competent jurisdiction. Each of the parties hereto (i) agrees that it shall not oppose the granting
of any such relief and (ii) hereby irrevocably waives any requirement for the security or posting of any bond in connection with
any such relief (it is understood that clause (i) of this sentence is not intended to, and shall not, preclude any party hereto
from litigating on the merits the substantive claim to which such remedy relates).









 


		j.	Submission to Jurisdiction. Each of the parties
hereto irrevocably agrees that any Proceeding with respect to this Agreement and the rights and obligations arising
hereunder, or for recognition and enforcement of any judgment in respect of this Agreement and the rights and obligations
arising hereunder brought by any other party hereto or its successors or assigns, shall be brought and determined exclusively
in the Court of Chancery of the State of Delaware, or in the event (but only in the event) that such court does not have subject
matter jurisdiction over such action or proceeding, in the federal courts sitting in the State of Delaware. Each of the parties
hereto agrees that mailing of process or other papers in connection with any such action or proceeding in the manner provided
in Section 8(d) or in such other manner as may be permitted by applicable Legal Requirements, will be valid and sufficient
service thereof. Each of the parties hereto hereby irrevocably submits with regard to any such action or proceeding for itself
and in respect of its property, generally and unconditionally, to the personal jurisdiction of the aforesaid courts and agrees
that it will not bring any action relating to this Agreement or any of the transactions contemplated by this Agreement in
any court or tribunal other than the aforesaid courts. Each of the parties hereto hereby irrevocably waives, and agrees not to
assert, by way of motion, as a defense, counterclaim, or otherwise, in any action or proceeding with respect to this Agreement and
the rights and obligations arising hereunder, or for recognition and enforcement of any judgment in respect of this Agreement and
the rights and obligations arising hereunder: (a) any claim that it is not personally subject to the jurisdiction of the above
named courts for any reason other than the failure to serve process in accordance with this Section 8(j); (b) any
claim that it or its property is exempt or immune from jurisdiction of any such court or from any legal process commenced in such
courts (whether through service of notice, attachment prior to judgment, attachment in aid of execution of judgment, execution
of judgment or otherwise); and (c) to the fullest extent permitted by the applicable Legal Requirements, any claim that (i) the
suit, action or proceeding in such court is brought in an inconvenient forum, (ii) the venue of such suit, action or proceeding
is improper, or (iii) this Agreement, or the subject matter hereof, may not be enforced in or by such courts.



 




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		k.	Waiver of Jury Trial. EACH PARTY ACKNOWLEDGES
AND AGREES THAT ANY CONTROVERSY WHICH MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT
ISSUES AND, THEREFORE, EACH SUCH PARTY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT
OF ANY LEGAL ACTION ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY. EACH PARTY
TO THIS AGREEMENT CERTIFIES AND ACKNOWLEDGES THAT: (A) NO REPRESENTATIVE OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR
OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT SEEK TO ENFORCE THE FOREGOING WAIVER IN THE EVENT OF A LEGAL ACTION; (B) SUCH PARTY
HAS CONSIDERED THE IMPLICATIONS OF THIS WAIVER; (C) SUCH PARTY MAKES THIS WAIVER VOLUNTARILY; AND (D) SUCH PARTY HAS BEEN INDUCED
TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 8(k).



 


		l.	Waiver. Any term or condition of this Agreement
may be waived at any time by the party that is entitled to the benefit thereof, but no such waiver shall be effective unless set
forth in a written instrument duly executed by or on behalf of the party waiving such term or condition, and no waiver by any
party of any default, misrepresentation, or breach of warranty or covenant hereunder, shall be deemed to extend to any prior or
subsequent default, misrepresentation, or breach of warranty, covenant or agreement hereunder or affect in any way any rights
arising by virtue of any such prior or subsequent occurrence. No failure or delay of any party in exercising any right or remedy
hereunder shall operate as a waiver thereof, and no waiver by any party of any term or condition of this Agreement, in any one
or more instances, shall be deemed to be or construed as a waiver of the same or any other term or condition of this Agreement
on any future occasion.



 




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		m.	Counterparts; Facsimile Signature. This Agreement
may be executed in one (1) or more counterparts, by original or facsimile (or other such electronically transmitted) signature,
each of which will be deemed an original, but all of which will constitute one and the same instrument. Any party executing this
Agreement by facsimile (or other such electronically transmitted) signature shall, upon request from another party hereto, promptly
deliver to the requesting party an original counterpart of such signature.



 


		n.	Rights Cumulative. All rights and remedies of
each of the parties under this Agreement will be cumulative, and the exercise of one or more rights or remedies will not preclude
the exercise of any other right or remedy available under this Agreement or applicable Legal Requirements.



 


		o.	Interpretation. (a) The words “hereof”,
“herein”, and “hereunder” and words of similar import, when used in this Agreement, shall refer to this
Agreement as a whole and not to any particular provision of this Agreement; (b) the words “date hereof,” when
used in this Agreement, shall refer to the date set forth in the Preamble; (c) the terms defined in the singular have a comparable
meaning when used in the plural, and vice versa; (d) the terms defined in the present tense have a comparable meaning when
used in the past tense, and vice versa; (e) any references herein to a specific Section or Article shall refer, respectively,
to Sections or Articles of this Agreement; (f) wherever the word “include”, “includes”, or “including”
is used in this Agreement, it shall be deemed to be followed by the words “without limitation”; (g) references
herein to any gender includes each other gender; (h) the word “or” shall not be exclusive; (i) the headings
herein are for convenience of reference only, do not constitute part of this Agreement and shall not be deemed to limit or otherwise
affect any of the provisions hereof; (j) any references herein to any Governmental Authority shall be deemed to also be a reference
to any successor Governmental Authority thereto; and (k) the parties hereto have participated jointly in the negotiation and drafting
of this Agreement and, in the event that an ambiguity or question of intent or interpretation arises, this Agreement shall be
construed as jointly drafted by the parties hereto and no presumption or burden of proof shall arise favoring or disfavoring any
party by virtue of the authorship of any provision of this Agreement.



 


[SIGNATURE PAGE TO FOLLOW]


 




    	9



     


    

 


IN WITNESS WHEREOF,
the parties hereto have executed this Waiver and Termination Agreement as of the date first set forth above.


 





	 	AVENUE THERAPEUTICS, INC.
	 	 	 
	 	By:	/s/ Lucy Lu
	 	Name:  	Lucy Lu
	 	Title:	CEO
	 	 	 
	 	FORTRESS BIOTECH, INC.
	 	 	 
	 	By:	/s/  Lindsay A. Rosenwald
	 	Name:  	 Lindsay A. Rosenwald
	 	Title:	President and CEO
	 	 	 
	 	INVAGEN PHARMACEUTICALS INC.
	 	 	 
	 	By:	/s/ Deepak Agarwal
	 	Name:  	Deepak Agarwal
	 	Title:	CFO




 


[Signature Page to
Waiver Agreement]


 




     


     


    

 


EXHIBIT
A


 


FOUNDERS AGREEMENT


 


[Exhibit A to Waiver Agreement]


 




     


     


    

 


EXHIBIT
B


 


MSA 


 


[Exhibit B to Waiver Agreement]