EXECUTION VERSION AGREEMENT AND PLAN OF MERGER By and Among BIOBLAST PHARMA LTD. TREBLAST LTD. AND ENLIVEX THERAPEUTICS LTD. Dated as of

AGREEMENT AND PLAN OF MERGER

BIOBLAST PHARMA LTD.

ENLIVEX THERAPEUTICS LTD.

Dated as of November 19, 2018

Exhibits and Schedules:

PLAN OF MERGER, dated as of November 19, 2018 (this "Agreement"), is by and among BIOBLAST PHARMA LTD., a company

formed under the laws of the State of Israel ("Bioblast"), TREBLAST LTD., a company formed under the laws of

the State of Israel and wholly owned by Bioblast ("Merger Sub"), and ENLIVEX THERAPEUTICS LTD., a company formed

under the laws of the State of Israel ("Enlivex").

WHEREAS, the respective

boards of directors of Bioblast (the "Bioblast Board") and Enlivex (the "Enlivex Board")

have unanimously adopted this Agreement, and such respective boards of directors have determined that the terms of this Agreement,

including the Merger are fair to, and in the respective best interests, of Bioblast and Enlivex, respectively, and their respective

shareholders and that, considering the financial position of Enlivex and Merger Sub, no reasonable concern exists that the Surviving

Company will be unable to fulfill the obligations of Enlivex to its creditors;

of Directors of Merger Sub has approved this Agreement and declared it advisable that Merger Sub enter into this Agreement and

consummate the Transactions, including the Merger, and has recommended that Bioblast, as its sole shareholder, approve and adopt

this Agreement, the Merger and the other Transactions;

WHEREAS, simultaneously

with the execution and delivery of this Agreement, as a condition to Enlivex's entering into this Agreement and as an inducement

thereto, Enlivex and certain shareholders of Bioblast identified in Schedule I, who together hold approximately 34.8% of

the issued and outstanding Bioblast Ordinary Shares, are entering into voting and support agreements, substantially in the form

attached as Exhibit A (the "Voting Agreement"), pursuant to which such shareholders are agreeing to take

specified actions in furtherance of the Merger, including voting their respective Bioblast Ordinary Shares in favor of the approval

of the Merger and adoption of this Agreement;

WHEREAS, the Bioblast

Board has recommended that its shareholders approve this Agreement;

WHEREAS, the Enlivex

Board has recommended that its shareholders approve this Agreement;

WHEREAS, for U.S. federal

income tax purposes, the parties hereto intend that the Merger qualify as a "reorganization" within the meaning of

Section 368(a) of the Code (as defined below) (the "Intended Tax Treatment"), and by executing this Agreement,

the parties hereto intend that this Agreement be adopted as a plan of reorganization within the meaning of Treasury Regulations

Sections 1.368-2(g) and 1.368-3; and

Merger Sub and Enlivex desire to make certain representations, warranties, covenants and agreements in connection with the Merger

and also to prescribe various conditions to the Merger.

consideration of the foregoing, the parties hereto, intending to be legally bound, hereby agree as follows:

1.01 The Merger. On the terms and subject to the

conditions set forth in this Agreement, and in accordance with Sections 314 through 327 of the Israeli Companies Law - 5759-1999

(the "Companies Law"), at the Effective Time, Merger Sub shall be merged with and into Enlivex (the "Merger").

At the Effective Time, the separate corporate existence of Merger Sub (as the target company, or Chevrat Ha'Ya'ad)

shall cease and Enlivex (as the absorbing company, or HaChevra Ha'Koletet) shall continue as the surviving corporation

in the Merger (the "Surviving Company"). As a result of the Merger, Enlivex shall (a) become a wholly owned

subsidiary of Bioblast, (b) continue to be governed by the Laws of the State of Israel, (c) have a registered office in the State

of Israel, and (d) succeed to and assume all of the rights, properties and obligations of Merger Sub in accordance with the Companies

Law, and the existing shareholders of Enlivex shall be entitled to the Merger Consideration in accordance with the provisions

1.02 Closing. Unless this Agreement shall have been

terminated in accordance with Section 8.01, the closing (the "Closing") of the Merger shall take place

at the offices of Yigal Arnon & Co., 1 Azrieli Center, Tel Aviv, Israel 6702101 (or pursuant to the electronic or other

remote exchange of all executed documents and other deliverables required by this Agreement to be delivered at Closing, including

pursuant to Article VII) at 7:00 a.m., Eastern time, on the third Business Day following the satisfaction or (to the extent

permitted by Law) waiver by the party or parties entitled to the benefits thereof of the conditions set forth in Article VII

(other than those conditions that by their nature are to be satisfied at the Closing, but subject to the satisfaction or (to

the extent permitted by Law) waiver of those conditions), or at such other place, time and date as shall be agreed in writing

between Bioblast and Enlivex. The date on which the Closing occurs is referred to in this Agreement as the "Closing Date."

1.03 Effective Time. As soon as practicable after

the determination of the date on which the Closing is to take place in accordance with Section 1.02, each of Enlivex and

Merger Sub shall (and Bioblast shall cause Merger Sub to), in coordination with each other, inform the Registrar of Companies

of the State of Israel (the "Israeli Registrar of Companies") that all conditions to the Merger under the Companies

Law and this Agreement have been met (together with any other documentation required to be submitted to the Israeli Registrar

of Companies, whether under this Agreement or the Merger Proposal, by the Israeli Registrar of Companies or otherwise) and setting

forth the proposed date for the date of effectiveness of the Merger on which the Israeli Registrar of Companies is requested to

issue a certificate evidencing the Merger in accordance with Section 323(5) of the Companies Law (the "Certificate of

Merger"). The Merger shall become effective upon the issuance by the Israeli Registrar of Companies of the Certificate

of Merger in accordance with Section 323(5) of the Companies Law (the time at which the Merger becomes effective is referred to

herein as the "Effective Time"). For the avoidance of doubt, the Parties intend that the Merger shall be declared

effective and that the issuance by the Israeli Registrar of Companies of the Certificate of Merger in accordance with Section

323(5) of the Companies Law shall both occur on the Closing Date, as a condition to Closing.

1.04 Effects. The Merger shall have the effects

set forth in this Agreement and as specified in the applicable provisions of the Companies Law. Without limiting the generality

of the foregoing, and subject thereto, at the Effective Time, the Surviving Company shall succeed to all the rights and properties

and the business of Merger Sub, and shall assume all of the debts, claims, liabilities and obligations of Merger Sub, Merger Sub

will be merged with and into Enlivex, and the separate corporate existence of Merger Sub will cease, and the Surviving Company

will become wholly owned (including with respect to any warrants, options or other securities) directly by Bioblast, all as provided

under the Companies Law.

1.05 Articles of Association of the Surviving Company.

At or prior to the Effective Time, the articles of association of Enlivex shall be amended by means of a shareholder vote and

restated to read in their entirety in the form of Exhibit B, and as so amended shall remain in effect from and after

the Effective Time as the articles of association of the Surviving Company (the "Surviving Company Articles")

until duly amended as provided therein or by applicable Law.

1.06 Directors and Officers of the Surviving Company.

At the Effective Time, the directors and officers of the Surviving Company, each to hold office in accordance with the Surviving

Company Articles and until their earlier resignation or removal or until their respective successors are duly elected or appointed

and qualified, shall be Enlivex's current directors and officers.

1.07 Contingent Value Right. Prior to the Effective

Time at a date determined by the Bioblast Board, Bioblast shareholders of record at such date shall be entitled to one CVR issued

by Bioblast in respect of each Bioblast Ordinary Share owned by them, subject to and in accordance with the terms and conditions

of the CVR Agreement. At or prior to the Effective Time, Bioblast and Enlivex shall authorize and duly adopt, execute and deliver,

together with the CVR Agent, the CVR Agreement.

Effect on Share Capital; Exchange of Certificates

2.01 Effect on Share Capital of Enlivex.

the Effective Time, by virtue of the Merger and without any action on the part of Bioblast, Merger Sub or Enlivex, or the holders

of any Enlivex Shares, all outstanding shares of Enlivex, other than Enlivex Ordinary Shares and any Dormant Shares, shall, in

accordance with the Enlivex Charter, be converted into Enlivex Ordinary Shares, and then, each Enlivex Ordinary Share (other than

any Dormant Share) shall be deemed transferred to Bioblast for no consideration other than the right to receive that number of

fully paid and nonassessable Bioblast Ordinary Shares equal to the Exchange Ratio. All such Bioblast Ordinary Shares to be issued