Exhibit 4.5

    

     

    

    
      FOURTH AMENDMENT TO RIGHTS AGREEMENT

       

      

      This FOURTH AMENDMENT (this
          “Amendment”), dated as of May 27, 2016, to the RIGHTS AGREEMENT, dated as of May 14, 2002, as amended on June 19, 2003, and as further amended on of February 3, 2011 and
          March 5, 2014 (the “Rights Agreement”), between BioSpecifics Technologies Corp., a Delaware corporation (the “Company”), and Worldwide Stock Transfer, LLC (as successor in interest to OTC Corporate Transfer Service Company) as Rights Agent (the “Rights Agent”).

       

        

      WHEREAS the Company may from time to time supplement or amend the Rights Agreement in accordance with the
          provisions of Section 27 thereof; and

       

        

      WHEREAS the Company desires to amend certain provisions of the Rights Agreement as set forth herein.

       

        

      NOW, THEREFORE, in consideration of the foregoing and the mutual agreements set forth in the Rights Agreement
          and this Amendment, the parties hereto hereby agree as follows:

       

        

      1.          Section 7. Section 7(a) of the Rights Agreement is hereby amended by deleting the reference to “May 31, 2016” in clause (i) thereof and inserting “May 31, 2018” in place thereof.

       

        

      2.          Exhibit B. Exhibit B to the Rights Agreement is hereby amended by deleting all references therein to “May 31, 2016” and inserting “May 31, 2018” in place thereof.

       

        

      3.          Exhibit C. Exhibit C to the Rights Agreement is hereby amended by deleting all references therein to “May 31, 2016” and inserting “May 31, 2018” in place thereof.

       

        

      4.          Full Force and Effect. Except as expressly amended hereby, the Rights Agreement shall continue in full force and effect in accordance with the provisions thereof.

       

        

      5.         Governing Law. This Amendment shall be deemed to be a contract made under the laws of the State of Delaware and for all purposes shall be governed by and construed in accordance with the laws of
          such State applicable to contracts to be made and performed entirely within such State; provided, however,
          that all provisions regarding the rights, duties and obligations of the Rights Agent shall be governed by and construed in accordance with the laws of the State of New York applicable to contracts made to be performed entirely within such State.

       

        

      6.          Counterparts; Effectiveness. This Amendment may be executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts
          shall together constitute but one and the same instrument. This Amendment shall be effective as of the date hereof.

       

        

      
        
          


      

      
      7.          Descriptive Headings. Descriptive headings of the several Sections of this Amendment are inserted for convenience only and shall not control or affect the meaning or construction of any
          of the provisions hereof.

       

        

      8.          Rights Agreement as Amended. From and after the date hereof, any reference to the Rights Agreement shall mean the Rights Agreement as amended hereby.

       

        

      9.         Severability. If any term, provision, covenant or restriction of this Amendment is held by a court of competent jurisdiction or other authority to be invalid, void or unenforceable, the
          remainder of the terms, provisions, covenants and restrictions of this Amendment shall remain in full force and effect and shall in no way be affected, impaired or invalidated.

       

        

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      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly executed as of the day and year
          first above written.

      

      

      	

            	
              BIOSPECIFICS TECHNOLOGIES CORP.

            
	

            	

            
	

            	
              By:

            	
              Thomas L. Wegman

            
	

            	

            	

            
	

            	
              Name:

            	
              Thomas L. Wegman

            
	

            	

            	

            
	

            	
              Title:

            	
              President

            


      

      

      	 	
              WORLDWIDE STOCK TRANSFER, LLC

            
	 	

            
	 	
              By:

            	
              Yonah J. Kopstick

            
	 	

            	

            
	 	
              Name:

            	
              Yonah J. Kopstick

            
	 	

            	

            
	 	
              Title:

            	
              Senior Vice President