EX-10.1



 Exhibit 10.1

REGISTRATION RIGHTS AGREEMENT 

This Registration Rights Agreement (this “Agreement”) is made and entered into as of January     , 2017,
by and among Cascadian Therapeutics, Inc., a Delaware corporation (the “Company”), and the several purchasers signatory hereto (each a “Purchaser” and collectively, the “Purchasers”). 

NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration, the
receipt and adequacy of which are hereby acknowledged, the Company and each of the Purchasers agree as follows: 

1.    Definitions. As used in this Agreement, the following terms shall have the following meanings: 

“Advice” has the meaning set forth in Section 6(d). 

“Affiliate” means, with respect to any Person, any other Person which directly or indirectly controls, is controlled by, or
is under common control with, such Person, as such terms are used and construed under Rule 405 under the Securities Act. 

“Agreement” has the meaning set forth in the Preamble. 

“Business Day” means a day, other than a Saturday or Sunday, on which banks in [New York City] are open for the general
transaction of business. 
 “Commission” means the Securities and Exchange Commission. 

“Common Stock” means the common stock, par value $0.0001 per share, of the Company. 

“Company” has the meaning set forth in the Preamble. 

“Effective Date” means the date that the Registration Statement filed pursuant to
Section 2(a) is first declared effective by the Commission. 
 “Effectiveness Deadline”
means, with respect to the Initial Registration Statement or the New Registration Statement, the thirtieth (30th) calendar day following the date the Initial Registration Statement or the New
Registration Statement is initially filed with the Commission (or, in the event the Commission reviews and has written or oral comments to the Initial Registration Statement or the New Registration Statement, the ninetieth (90th) calendar day following the date the Initial Registration Statement or the New Registration Statement is initially filed with the Commission); provided, however, that if the Company is
notified by the Commission that the Initial Registration Statement or the New Registration Statement will not be reviewed or is no longer subject to further review and comments, the Effectiveness Deadline as to such Registration Statement shall be
the fifth (5th) Trading Day following the date on which the Company is so notified if such date precedes the dates otherwise required above; provided, further, that if the Effectiveness
Deadline falls on a Saturday, Sunday or other day that the Commission is closed for business, the Effectiveness Deadline shall be extended to the next Business Day on which the Commission is open for business. 

“Effectiveness Period” has the meaning set forth in Section 2(b). 

“Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated
thereunder. 
 “Filing Deadline” means, with respect to the Initial Registration Statement required to be filed pursuant
to Section 2(a), the one hundredth (100th) calendar day following the date hereof, provided, however, that if the Filing Deadline falls on a Saturday, Sunday or
other day that the Commission is closed for business, the Filing Deadline shall be extended to the next business day on which the Commission is open for business. 







 “Holder” or “Holders” means the holder or holders, as the case
may be, from time to time of Registrable Securities. 
 “Indemnified Party” has the meaning set forth in
Section 5(c). 
 “Indemnifying Party” has the meaning set forth in
Section 5(c). 
 “Initial Registration Statement” means the initial Registration Statement filed
pursuant to Section 2(a) of this Agreement. 
 “Losses” has the meaning set forth in
Section 5(a). 
 “New Registration Statement” has the meaning set forth in
Section 2(a). 
 “Person” means an individual or corporation, partnership, trust, incorporated
or unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind. 

“Proceeding” means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or
partial proceeding, such as a deposition), whether commenced or threatened. 
 “Prospectus” means the prospectus included
in a Registration Statement (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A or Rule 430B promulgated
under the Securities Act), as amended or supplemented by any prospectus supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by a Registration Statement, and all other amendments and supplements
to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus. 

“Purchaser” or “Purchasers” has the meaning set forth in the Preamble. 

“Registrable Securities” means the shares of Common Stock issued or issuable upon conversion of the Shares (subject to
appropriate adjustment for share splits, share dividends, combination of shares, recapitalizations or other such events relating to the Common Stock from time to time after the date hereof) (collectively, “Existing Shares”) and any
securities issued or issuable upon any stock split, dividend or other distribution, recapitalization or similar event with respect to the foregoing, provided, that the Holder has completed and delivered to the Company a Selling Stockholder
Questionnaire; and provided, further, that with respect to a particular Holder, such Holder’s Existing Shares shall cease to be Registrable Securities upon the earliest to occur of the following: (A) a sale pursuant to a
Registration Statement or Rule 144 under the Securities Act; or (B) the date such Existing Shares are eligible for sale without restriction under Rule 144. 

“Registration Statements” means any one or more registration statements of the Company filed under the Securities Act that
covers the resale of any of the Registrable Securities pursuant to the provisions of this Agreement (including without limitation the Initial Registration Statement, the New Registration Statement and any Remainder Registration Statements),
including the Prospectus, amendments and supplements to each such registration statement or Prospectus, including, pre- and post-effective amendments, all exhibits and all material incorporated by reference or
deemed to be incorporated by reference in such registration statements. 
 “Remainder Registration Statement” has the
meaning set forth in Section 2(a). 
 “Rule 144” means Rule 144
promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

  
 2 








 “Rule 415” means Rule 415 promulgated by the Commission
pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Rule 424” means Rule 424 promulgated by the Commission pursuant to the Securities Act, as such
Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“SEC Guidance” means (i) any publicly-available written or oral guidance, comments, requirements or requests of the
Commission staff and (ii) the Securities Act. 
 “Securities Act” means the Securities Act of 1933, as amended, and
the rules and regulations promulgated thereunder. 
 “Selling Stockholder Questionnaire” means a questionnaire in the
form attached as Annex B hereto, or such other form of questionnaire as may reasonably be adopted by the Company from time to time. 

“Shares” means the shares of Series E Convertible Preferred Stock, par value $0.0001 per share, of the Company issued to the
Purchasers on the date hereof. 
 “Trading Day” means a day on which the Common Stock is listed or quoted and traded on
the NASDAQ Global Market, or, if the NASDAQ Global Market is not the principal trading market for the Common Stock, then on the principal securities exchange or securities market on which the Common Stock is then traded. 

2.     Registration. 

(a)    On or prior to the Filing Deadline, the Company shall prepare and file with the Commission a Registration Statement
covering the resale of all of the Registrable Securities not already covered by an existing and effective Registration Statement for an offering to be made on a continuous basis pursuant to Rule 415 or, if Rule 415 is not available for
offers and sales of the Registrable Securities, by such other means of distribution of Registrable Securities as the Holders may reasonably specify (the “Initial Registration Statement”). The Initial Registration Statement
shall be on Form S-3 (except if the Company is then ineligible to register for resale the Registrable Securities on Form S-3, in which case such registration
shall be on such other form available to register for resale the Registrable Securities as a secondary offering) subject to the provisions of Section 2(d) and shall contain (except if otherwise required pursuant to
written comments received from the Commission upon a review of such Registration Statement) the “Plan of Distribution” section attached hereto as Annex A (which may be modified to respond to comments, if any, provided by the
Commission). Notwithstanding the registration obligations set forth in this Section 2, in the event the Commission informs the Company that all of the Registrable Securities cannot, as a result of the application of
Rule 415, be registered for resale as a secondary offering on a single registration statement, the Company agrees to promptly (i) inform each of the holders thereof and use its commercially reasonable efforts to file amendments to the
Initial Registration Statement as required by the Commission and/or (ii) withdraw the Initial Registration Statement and file a new registration statement (a “New Registration Statement”), in either case covering the maximum
number of Registrable Securities permitted to be registered by the Commission, on Form S-3 or such other form available to register for resale the Registrable Securities as a secondary offering;
provided, however, that prior to filing such amendment or New Registration Statement, the Company shall be obligated to use its commercially reasonable efforts to advocate with the Commission for the registration of all of the Registrable
Securities in accordance with the SEC Guidance, including without limitation, the Manual of Publicly Available Telephone Interpretations D.29. In the event the Company amends the Initial Registration Statement or files a New Registration Statement,
as the case may be, under clauses (i) or (ii) above, the Company will use its commercially reasonable efforts to file with the Commission, as promptly as allowed by Commission or SEC Guidance provided to the Company or to registrants of
securities in general, one or more registration statements on Form S-3 or such other form available to register for resale those Registrable Securities that were not registered for resale on the Initial
Registration Statement, as amended, or the New Registration Statement (the “Remainder Registration Statements”). 

  
 3 








 (b)    The Company shall use its best efforts to cause each Registration
Statement to be declared effective by the Commission as soon as practicable and, with respect to the Initial Registration Statement or the New Registration Statement, as applicable, no later than the Effectiveness Deadline (including filing with the
Commission a request for acceleration of effectiveness in accordance with Rule 461 promulgated under the Securities Act), and shall use its reasonable best efforts to keep each Registration Statement continuously effective under the Securities
Act for so long as Registrable Securities remain outstanding (the “Effectiveness Period”). The Company shall telephonically request effectiveness of a Registration Statement as of 5:00 P.M. New York City time on a Trading
Day. The Company shall promptly notify the Holders via facsimile or electronic mail of the Commission’s verbal confirmation of effectiveness of a Registration Statement on the same Trading Day that the Company telephonically confirms
effectiveness with the Commission, which date of confirmation shall initially be the date requested for effectiveness of such Registration Statement. The Company shall, by 9:30 A.M. New York City time on the first Trading Day after the
Effective Date, file a final Prospectus with the Commission, as required by Rule 424(b).
 (c)    The Company shall
provide prompt notice to each Holder of the anticipated filing date of the Registration Statement. Each Holder agrees to furnish to the Company a completed Selling Stockholder Questionnaire on the later of (i) not more than ten
(10) Trading Days following the date of this Agreement, or (ii) at least thirty (30) Trading Days prior the filing date of a Registration Statement, unless such Holder receives notice of such anticipated filing date within such thirty
(30)-day period, in which case such period shall be extended to five (5) Trading Days from the date of receipt of such notice. At least five (5) Trading Days prior to the first anticipated filing
date of a Registration Statement for any registration under this Agreement, the Company will notify each Holder of the information the Company requires from that Holder other than the information contained in the Selling Stockholder Questionnaire,
if any, which shall be completed and delivered to the Company promptly upon request and, in any event, within two (2) Trading Days prior to the applicable anticipated filing date. Each Holder further agrees that it shall not be entitled to
be named as a selling securityholder in the Registration Statement or use the Prospectus for offers and resales of Registrable Securities at any time, unless such Holder has returned to the Company a completed and signed Selling Stockholder
Questionnaire and a response to any requests for further information as described in the previous sentence. If a Holder of Registrable Securities returns a Selling Stockholder Questionnaire or a request for further information, in either case, after
its respective deadline, the Company shall use its commercially reasonable efforts to take such actions as are required to name such Holder as a selling security holder in the Registration Statement and to include (to the extent not theretofore
included) in the Registration Statement the Registrable Securities identified in such late Selling Stockholder Questionnaire or request for further information. The Company shall not be required to file a
pre-effective or post-effective amendment to the Registration Statement to include a Holder that returned the Selling Stockholder Questionnaire after the deadline described in this section. Each Holder
acknowledges and agrees that the information in the Selling Stockholder Questionnaire or request for further information as described in this Section 2(c) will be used by the Company in the preparation of the
Registration Statement and hereby consents to the inclusion of such information in the Registration Statement. 

(d)    In the event that Form S-3 is not available for the registration of
the resale of Registrable Securities hereunder, the Company shall (i) register the resale of the Registrable Securities on another appropriate form reasonably acceptable to the Holders and (ii) undertake to register the Registrable
Securities on Form S-3 promptly after such form is available, provided that the Company shall maintain the effectiveness of the Registration Statement then in effect until such time as a
Registration Statement on Form S-3 covering the Registrable Securities has been declared effective by the Commission. 

3.    Registration Procedures 

In connection with the Company’s registration obligations hereunder, the Company shall: 

(a)    Except as otherwise set forth in Section 2(c), above, not less than three (3) Trading Days prior to the
filing of each Registration Statement and not less than two (2) Trading Days prior to the filing of any related Prospectus or any amendment or supplement thereto (except for Annual Reports on
Form 10-K and Current Reports on Form 10-Q and 8-K and any similar or successor reports), (i) furnish to the
Holder copies of such Registration Statement, Prospectus or amendment or supplement thereto, as proposed to be filed, which documents will be subject to the review of such Holder (it being acknowledged and agreed that if a Holder does not object to
or 

  
 4 








 
comment on the aforementioned documents within such three (3) Trading Day or two (2) Trading Day period, as the case may be, then the Holder shall be deemed to have consented to and
approved the use of such documents) and (ii) use commercially reasonable efforts to cause its officers and directors, counsel and independent registered public accountants to respond to such inquiries as shall be necessary, including in the
reasonable opinion of respective counsel to each Holder, to conduct a reasonable investigation within the meaning of the Securities Act in order to be able to respond to reasonable inquiries from Holders. The Company shall not file any
Registration Statement or amendment or supplement thereto in a form to which a Holder reasonably objects in good faith, provided that, the Company is notified of such objection in writing within the three (3) Trading Day or two (2) Trading
Day period described above, as applicable. 
 (b)     (i) Prepare and file with the Commission such amendments
(including post-effective amendments) and supplements, to each Registration Statement and the Prospectus used in connection therewith as may be necessary to keep such Registration Statement continuously effective as to the applicable Registrable
Securities for its Effectiveness Period; (ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement (subject to the terms of this Agreement), and, as so supplemented or amended, to be filed pursuant to
Rule 424; (iii) respond as promptly as reasonably practicable to any comments received from the Commission with respect to each Registration Statement or any amendment thereto and, as promptly as reasonably possible, provide the Holders
true and complete copies of all correspondence from and to the Commission relating to such Registration Statement that pertains to the Holders as “Selling Stockholders” but not any comments that would result in the disclosure to the
Holders of material and non-public information concerning the Company; and (iv) comply with the provisions of the Securities Act and the Exchange Act with respect to the disposition of all Registrable
Securities covered by a Registration Statement until such time as all of such Registrable Securities shall have been disposed of (subject to the terms of this Agreement) in accordance with the intended methods of disposition by the Holders thereof
as set forth in such Registration Statement as so amended or in such Prospectus as so supplemented; provided, however, that each Purchaser shall be responsible for the delivery of the Prospectus to the Persons to whom such Purchaser sells any
of the Shares (including in accordance with Rule 172 under the Securities Act), and each Purchaser agrees to dispose of Registrable Securities in compliance with the “Plan of Distribution” described in the Registration Statement and
otherwise in compliance with applicable federal and state securities laws. In the case of amendments and supplements to a Registration Statement which are required to be filed pursuant to this Agreement (including pursuant to this
Section 3(b)) by reason of the Company filing a report on Form 10-K, Form 10-Q or Form 8-K or
any analogous report under the Exchange Act, the Company shall have incorporated such report by reference into such Registration Statement, if applicable, or shall file such amendments or supplements with the Commission on the same day on which the
Exchange Act report which created the requirement for the Company to amend or supplement such Registration Statement was filed. 

(c)    Notify the Holders (which notice shall, pursuant to clauses (iii) through (vi) hereof, be accompanied by
an instruction to suspend the use of the Prospectus until the requisite changes have been made) as promptly as reasonably practicable (and, in the case of (i)(A) below, not less than one (1) Trading Day prior to such filing) and (if
requested by any such Holder) confirm such notice in writing no later than one (1) Trading Day following the day: (i)(A) when a Prospectus or any Prospectus supplement or post-effective amendment to a Registration Statement is proposed to
be filed; (B) when the Commission notifies the Company whether there will be a “review” of such Registration Statement and whenever the Commission comments in writing on any Registration Statement (in which case the Company shall
provide to each of the Holders true and complete copies of all comments that pertain to the Holders as a “Selling Stockholder” or to the “Plan of Distribution” and all written responses thereto, but not information that the
Company believes would constitute material and non-public information); and (C) with respect to each Registration Statement or any post-effective amendment, when the same has become effective;
(ii) of any request by the Commission or any other Federal or state governmental authority for amendments or supplements to a Registration Statement or Prospectus or for additional information that pertains to the Holders as “Selling
Stockholders” or the “Plan of Distribution”; (iii) of the issuance by the Commission or any other federal or state governmental authority of any stop order suspending the effectiveness of a Registration Statement covering any or
all of the Registrable Securities or the initiation of any Proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the
Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any Proceeding for such purpose; (v) of the occurrence of any event or passage of time that makes the financial statements included in a Registration
Statement ineligible for inclusion therein or any statement made in such Registration Statement or Prospectus or any document incorporated or deemed to be incorporated therein by 

  
 5 








 
reference untrue in any material respect or that requires any revisions to such Registration Statement, Prospectus or other documents so that, in the case of such Registration Statement or the
Prospectus, as the case may be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, form of
prospectus or supplement thereto, in light of the circumstances under which they were made), not misleading and (vi) of the occurrence or existence of any pending corporate development with respect to the Company that the Company believes may
be material and that, in the determination of the Company, makes it not in the best interest of the Company to allow continued availability of a Registration Statement or Prospectus, provided that, any and all such information shall remain
confidential to each Holder until such information otherwise becomes public, unless disclosure by a Holder is required by law; and provided, further, that notwithstanding each Holder’s agreement to keep such information
confidential, each such Holder makes no acknowledgement that any such information is material, non-public information. 

(d)    Use commercially reasonable efforts to avoid the issuance of, or, if issued, obtain the withdrawal of (i) any
order suspending the effectiveness of a Registration Statement, or (ii) any suspension of the qualification (or exemption from qualification) of any of the Registrable Securities for sale in any jurisdiction, as soon as practicable. 

(e)    If requested by a Holder, furnish to such Holder, without charge, at least one conformed copy of each Registration
Statement and each amendment thereto and all exhibits to the extent requested by such Person (including those previously furnished or incorporated by reference) promptly after the filing of such documents with the Commission; provided, that
the Company shall have no obligation to provide any document pursuant to this clause that is available on the Commission’s EDGAR system. 

(f)    Prior to any resale of Registrable Securities by a Holder, use its commercially reasonable efforts to register or
qualify or cooperate with the selling Holders in connection with the registration or qualification (or exemption from the registration or qualification) of such Registrable Securities for the resale by the Holder under the securities or Blue Sky
laws of such jurisdictions within the United States as any Holder reasonably requests in writing, to keep each registration or qualification (or exemption therefrom) effective during the Effectiveness Period and to do any and all other acts or
things reasonably necessary to enable the disposition in such jurisdictions of the Registrable Securities covered by each Registration Statement; provided, that the Company shall not be required to qualify generally to do business in any
jurisdiction where it is not then so qualified, subject the Company to any material tax in any such jurisdiction where it is not then so subject or file a general consent to service of process in any such jurisdiction. 

(g)    If requested by a Holder, cooperate with such Holder to facilitate the timely preparation and delivery of
certificates representing Registrable Securities to be delivered to a transferee pursuant to the Registration Statement, which certificates shall be free, to the extent permitted under law, of all restrictive legends, and to enable such Registrable
Securities to be in such denominations and registered in such names as any such Holders may reasonably request. 

(h)    Following the occurrence of any event contemplated by Section 3(c), as promptly as
reasonably practicable (taking into account the Company’s good faith assessment of any adverse consequences to the Company and its stockholders of the premature disclosure of such event), prepare a supplement or amendment, including a
post-effective amendment, to the affected Registration Statements or a supplement to the related Prospectus or any document incorporated or deemed to be incorporated therein by reference, and file any other required document so that, as thereafter
delivered, no Registration Statement nor any Prospectus will contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus,
form of prospectus or supplement thereto, in light of the circumstances under which they were made), not misleading. If the Company notifies the Holders in accordance with clauses (iii) through (vi) of
Section 3(c) above to suspend the use of any Prospectus until the requisite changes to such Prospectus have been made, then the Holders shall suspend use of such Prospectus. The Company will use its commercially
reasonable efforts to ensure that the use of the Prospectus may be resumed as promptly as is practicable and to update the Registration Statement to the extent required by applicable law or regulation to ensure that it contains materially accurate
information with respect to the Company and no omission that would make the statements contained therein materially misleading. For the avoidance of doubt, no suspension of the availability of a


  
 6 








 
Registration Statement and Prospectus hereunder shall be deemed to restrict the sale of any Registrable Securities in any other manner that may be permitted by applicable law (including, to the
extent available, Rule 144). The Company shall be entitled to exercise its right under this Section 3(h) to suspend the availability of a Registration statement and Prospectus for a period not to exceed sixty
(60) calendar days (which need not be consecutive days) in any twelve (12) month period. 
 (i)    The Company
may require each selling Holder to furnish to the Company a certified statement as to (i) the number of shares of Common Stock beneficially owned by such Holder and any Affiliate thereof, (ii) any Financial Industry Regulatory Authority
(“FINRA”) affiliations, (iii) any natural persons who have the power to vote or dispose of shares of Common Stock and (iv) any other information as may be requested by the Commission, FINRA or any state securities
commission. 
 (j)    The Company shall cooperate with any registered broker through which a Holder proposes to resell
its Registrable Securities in effecting a filing with FINRA pursuant to FINRA Rule 2710 as requested by any such Holder and the Company shall pay the filing fee required for the first such filing within two (2) Business Days of the request
therefor. 
 (k)    With a view to making available to each Holder the benefits of Rule 144 and any other similar rule
or regulation of the Commission that may at any time permit such Holder to sell securities of the Company to the public without registration, the Company agrees (until all of the Registrable Securities have been sold or transferred under a
Registration Statement or pursuant to Rule 144) to use its commercially reasonable efforts to: 
  

	 	(i)	make and keep public information available, as those terms are understood and defined in Rule 144; 

  

	 	(ii)	file with the Commission in a timely manner (or obtain extensions in respect thereof and file within the applicable grace period) all reports and other documents required of the Company under the Securities Act and the
Exchange Act so long as the Company remains subject to such requirements; and 

  

	 	(iii)	furnish to such Holder, so long as such Holder owns any Registrable Securities, promptly upon written request (i) a written statement by the Company, if true, that it has complied with the reporting requirements of
Rule 144, the Securities Act and the Exchange Act, (ii) to the extent not publicly available through the Commission’s EDGAR database, a copy of the most recent annual or quarterly report of the Company and such other reports and documents
so filed by the Company with the Commission, and (iii) such other information as may be reasonably requested by such Holder in connection with such Holder’s compliance with any rule or regulation of the Commission which permits the selling
of any such securities without registration. 

 4.    Registration Expenses. All fees and
expenses incident to the Company’s performance of or compliance with its obligations under this Agreement (excluding any underwriting discounts and selling commissions and all legal fees and expenses of legal counsel for any Holder) shall be
borne by the Company whether or not any Registrable Securities are sold pursuant to a Registration Statement. The fees and expenses referred to in the foregoing sentence shall include, without limitation, (i) all registration and filing
fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with the NASDAQ Global Market or any other trading market on which the Common Stock is then listed for trading, (B) with respect to
compliance with applicable state securities or Blue Sky laws (including, without limitation, fees and disbursements of counsel for the Company in connection with Blue Sky qualifications or exemptions of the Registrable Securities and determination
of the eligibility of the Registrable Securities for investment under the laws of such jurisdictions as requested by the Holders) and (C) if not previously paid by the Company in connection with
Section 3(j) above, with respect to any filing that may be required to be made by any broker through which a Holder intends to make sales of Registrable Securities with FINRA pursuant to the FINRA Rule 2710, so
long as the broker is receiving no more than a customary brokerage commission in connection with such sale, (ii) printing expenses (including, without limitation, expenses of printing certificates for Registrable Securities and of printing
prospectuses if the printing of prospectuses is reasonably requested by the Holders of a majority of the Registrable Securities included 

  
 7 








 
in the Registration Statement), (iii) messenger, telephone and delivery expenses, (iv) reasonable fees and disbursements of counsel for the Company, (v) reasonable fees and
disbursements of one (1) counsel to the Holders, in an amount not to exceed $25,000, (vi) Securities Act liability insurance, if the Company so desires such insurance, and (vii) reasonable fees and expenses of all other Persons
retained by the Company in connection with the consummation of the transactions contemplated by this Agreement. In addition, the Company shall be responsible for all of its internal expenses incurred in connection with the consummation of the
transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of its officers and employees performing legal or accounting duties), the expense of any annual audit and the fees and expenses incurred in
connection with the listing of the Registrable Securities on any securities exchange as required hereunder. In no event shall the Company be responsible for any underwriting, broker or similar fees or commissions of any Holder or, except to the
extent provided for herein, any legal fees or other costs of the Holders. 
 5.    Indemnification. 

(a)    Indemnification by the Company. The Company shall, notwithstanding any termination of this Agreement,
indemnify, defend and hold harmless each Holder, the officers, directors, agents, partners, members, managers and employees of each of them, each Person who controls any such Holder (within the meaning of Section 15 of the Securities Act or
Section 20 of the Exchange Act) and the officers, directors, partners, members, managers agents and employees of each such controlling Person, to the fullest extent permitted by applicable law, from and against any and all losses, claims,
damages, liabilities, costs (including, without limitation, reasonable costs of preparation and investigation and reasonable attorneys’ fees) and expenses (collectively, “Losses”), as incurred, that arise out of or are based
upon (i) any untrue statement of a material fact contained in any Registration Statement, any Prospectus or any form of prospectus or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any
omission to state a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus or supplement thereto, in light of the circumstances under which they were made) not
misleading, or (ii) any violation by the Company of the Securities Act, Exchange Act or any state securities law or any rule or regulation thereunder, in connection with the performance of its obligations under this Agreement, except to
the extent, but only to the extent, that (A) such untrue statements, or omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such
information relates to such Holder or such Holder’s proposed method of distribution of Registrable Securities and was reviewed and approved in writing by such Holder expressly for use in the Registration Statement, such Prospectus or such
form of Prospectus or in any amendment or supplement thereto (it being understood that each Holder has approved Annex A hereto for this purpose) or (B) in the case of an occurrence of an event of the type specified in
Section 3(c)(iii)-(vi), related to the use by a Holder of an outdated or defective Prospectus after the Company has notified such Holder in writing that the Prospectus is outdated or defective and prior to the
receipt by such Holder of the Advice contemplated and defined in Section 6(d) below, to the extent that following the receipt of the Advice the misstatement or omission giving rise to such Loss would have been
corrected or (C) to the extent that any such Losses arise out of the Purchaser’s (or any other indemnified Person’s) failure to send or give a copy of the Prospectus or supplement (as then amended or supplemented), if required,
pursuant to Rule 172 under the Securities Act (or any successor rule) to the Persons asserting an untrue statement or omission at or prior to the written confirmation of the sale of Registrable Securities to such Person if such statement or
omission was corrected in such Prospectus or supplement. The Company shall notify the Holders promptly of the institution, threat or assertion of any Proceeding arising from or in connection with the transactions contemplated by this Agreement
of which the Company is aware. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of an Indemnified Party (as defined in Section 5(c)) and shall survive the
transfer of the Registrable Securities by the Holders. 
 (b)    Indemnification by Holders. Each Holder shall,
severally and not jointly, indemnify and hold harmless the Company, its directors, officers, agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act and Section 20 of the Exchange
Act), and the directors, officers, agents or employees of such controlling Persons, to the fullest extent permitted by applicable law, from and against all Losses, as incurred, based solely upon any untrue statement of a material fact contained in
any Registration Statement, any Prospectus, or any form of prospectus, or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission of a material fact required to be stated therein or
necessary to make the statements therein (in the case of any Prospectus, or any form of prospectus or supplement 

  
 8 








 
thereto, in light of the circumstances under which they were made) not misleading (i) to the extent that such untrue statements or omissions are based solely upon information regarding such
Holder furnished in writing to the Company by such Holder expressly for use therein or (ii) to the extent that such information relates to such Holder or such Holder’s proposed method of distribution of Registrable Securities and was
reviewed and approved in writing by such Holder expressly for use in a Registration Statement (it being understood that the Holder has approved Annex A hereto for this purpose), such Prospectus or such form of Prospectus or in any amendment
or supplement thereto or (iii) in the case of an occurrence of an event of the type specified in Section 3(c)(iii)-(vi), to the extent related to the use by such Holder of an outdated or defective Prospectus
after the Company has notified such Holder in writing that the Prospectus is outdated or defective and prior to the receipt by such Holder of the Advice contemplated in Section 6(d), but only if and to the extent that
following the receipt of the Advice, the misstatement or omission giving rise to such Losses would have been corrected; provided that, the foregoing indemnity shall not apply to amounts paid in settlement of any such Losses if such settlement
is effected without the consent of the Holder (which consent shall not be unreasonably withheld, conditioned or delayed). In no event shall the liability of any selling Holder hereunder be greater in amount than the dollar amount of the net
proceeds received by such Holder upon the sale of the Registrable Securities giving rise to such indemnification obligation. 

(c)    Conduct of Indemnification Proceedings. If any Proceeding shall be brought or asserted against any Person
entitled to indemnity hereunder (an “Indemnified Party”), such Indemnified Party shall promptly notify the Person from whom indemnity is sought (the “Indemnifying Party”) in writing, and the Indemnifying Party shall
have the right to assume the defense thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party and the payment of all reasonable fees and expenses incurred in connection with defense thereof; provided, that
the failure of any Indemnified Party to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except (and only) to the extent that it shall be finally determined by a court of
competent jurisdiction (which determination is not subject to appeal or further review) that such failure shall have proximately, materially and adversely prejudiced the Indemnifying Party. 

An Indemnified Party shall have the right to employ separate counsel in any such Proceeding and to participate in the defense thereof, but
the fees and expenses of such counsel shall be at the expense of such Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed
promptly to assume the defense of such Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3) the named parties to any such Proceeding (including any impleaded parties) include both
such Indemnified Party and the Indemnifying Party, and such Indemnified Party shall have been advised by counsel that a conflict of interest exists if the same counsel were to represent such Indemnified Party and the Indemnifying Party (in which
case, if such Indemnified Party notifies the Indemnifying Party in writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying Party shall not have the right to assume the defense thereof and such
counsel shall be at the expense of the Indemnifying Party); provided, that the Indemnifying Party shall not be liable for the fees and expenses of more than one separate firm of attorneys at any time for all Indemnified Parties. The
Indemnifying Party shall not be liable for any settlement of any such Proceeding effected without its written consent, which consent shall not be unreasonably withheld, delayed or conditioned. No Indemnifying Party shall, without the prior
written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any Indemnified Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on
claims that are the subject matter of such Proceeding. 
 Subject to the terms of this Agreement, all fees and expenses of the Indemnified
Party (including reasonable fees and expenses to the extent incurred in connection with investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section 5) shall be paid to the Indemnified
Party, as incurred, within twenty (20) Trading Days of written notice thereof to the Indemnifying Party; provided, that the Indemnified Party shall promptly reimburse the Indemnifying Party for that portion of such fees and expenses
applicable to such actions for which such Indemnified Party is finally judicially determined to not be entitled to indemnification hereunder). The failure to deliver written notice to the Indemnifying Party within a reasonable time of the
commencement of any such action shall not relieve such Indemnifying Party of any liability to the Indemnified Party under this Section 5, except to the extent that the Indemnifying Party is materially and adversely
prejudiced in its ability to defend such action. 

  
 9 








 (d)    Contribution. If a claim for indemnification under
Section 5(a) or 5(b) is unavailable to an Indemnified Party or insufficient to hold an Indemnified Party harmless for any Losses, then each Indemnifying Party, in lieu of indemnifying such Indemnified
Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with the
actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The relative fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things,
whether any action in question, including any untrue statement of a material fact or omission of a material fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties’
relative intent, knowledge, access to information and opportunity to correct or prevent such action, statement or omission. The amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations
set forth in this Agreement, any reasonable attorneys’ or other reasonable fees or expenses incurred by such party in connection with any Proceeding to the extent such party would have been indemnified for such fees or expenses if the
indemnification provided for in this Section 5 was available to such party in accordance with its terms. 
 The
parties hereto agree that it would not be just and equitable if contribution pursuant to this Section 5(d) were determined by pro rata allocation or by any other method of allocation that does not take into account the
equitable considerations referred to in the immediately preceding paragraph. Notwithstanding the provisions of this Section 5(d), (A) no Holder shall be required to contribute, in the aggregate, any amount in
excess of the amount by which the net proceeds actually received by such Holder from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages that such Holder has otherwise been required to pay by reason of
such untrue statement or omission and (B) no contribution will be made under circumstances where the maker of such contribution would not have been required to indemnify the Indemnified Party under the fault standards set forth in this
Section 5. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any Person who was not guilty of such fraudulent
misrepresentation. 
 6.    Miscellaneous. 

(a)    Remedies. In the event of a breach by the Company or by a Holder of any of their obligations under this
Agreement, each Holder or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement, including recovery of damages, will be entitled to specific performance of its rights under this
Agreement. The Company and each Holder agree that monetary damages would not provide adequate compensation for any losses incurred by reason of a breach by it of any of the provisions of this Agreement and hereby further agrees that, in the
event of any action for specific performance in respect of such breach, it shall waive the defense that a remedy at law would be adequate. 

(b)    No Piggyback on Registrations; Prohibition on Filing Other Registration Statements. Neither the Company
nor any of its security holders (other than the Holders in such capacity pursuant hereto) may include securities of the Company in a Registration Statement other than the Registrable Securities and the Company shall not prior to the Effective Date
enter into any agreement providing any such right to any of its security holders. The Company shall not file with the Commission a registration statement relating to an offering for its own account under the Securities Act of any of its equity
securities other than a registration statement in connection with employee equity awards or in connection with an acquisition until the earlier of (i) the date that is thirty (30) days after the Initial Registration Statement or New
Registration Statement, as the case may be, is declared effective or (ii) the date that all Registrable Securities are eligible for resale by non-affiliates without volume or manner of sale restrictions
under Rule 144 and without the requirement for the company to be in compliance with the current public information requirements under Rule 144. For the avoidance of doubt, the Company shall not be prohibited from preparing and filing with the
Commission a registration statement relating to an offering of Common Stock by existing stockholders of the Company under the Securities Act pursuant to the terms of registration rights held by such stockholder or from filing amendments to
registration statements filed prior to the date of this Agreement. 
 (c)    Compliance. Each Holder
covenants and agrees that it will comply with the prospectus delivery requirements of the Securities Act as applicable to it (unless an exemption therefrom is available) in connection with sales of Registrable Securities pursuant to the Registration
Statement and shall sell the Registrable Securities only in accordance with a method of distribution described in the Registration Statement 

  
 10 








 (d)    Discontinued Disposition. By its acquisition of
Registrable Securities, each Holder agrees that, upon receipt of a notice from the Company of the occurrence of any event of the kind described in Section 3(c)(iii)-(vi), such Holder will forthwith discontinue
disposition of such Registrable Securities under a Registration Statement until it is advised in writing (the “Advice”) by the Company that the use of the applicable Prospectus (as it may have been supplemented or amended) may be
resumed. The Company will use its commercially reasonable efforts to ensure that the use of the Prospectus may be resumed as promptly as is reasonably practicable.

(e)    Subsequent Registration Rights. Until the Initial Registration Statement required hereunder is declared
effective by the Commission, the Company shall not enter into any agreement granting any registration rights with respect to any of its securities to any Person without the written consent of Holders representing no less than a majority of the then
outstanding Registrable Securities; provided, that this Section 6(e) shall not prohibit the Company from fulfilling its obligations under any other registration rights agreements existing as of the date hereof.  

(f)    No Inconsistent Agreements. Neither the Company nor any of its Subsidiaries has entered, as of the date
hereof, nor shall the Company or any of its Subsidiaries, on or after the date hereof, enter into any agreement with respect to its securities, that would have the effect of impairing the rights granted to the Holders in this Agreement or otherwise
conflicts with the provisions hereof. 
 (g)    Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or supplemented, or waived unless the same shall be in writing and signed by the Company and Holders holding no less than a majority of the then outstanding Registrable
Securities, provided that any party may give a waiver as to itself, provided further that if any amendment, modification or waiver disproportionately and adversely impacts a Holder, the consent of such disproportionately impact Holder shall also be
required. Notwithstanding the foregoing, a waiver or consent to depart from the provisions hereof with respect to a matter that relates exclusively to the rights of Holders and that does not directly or indirectly affect the rights of
other Holders may be given by Holders of all of the Registrable Securities to which such waiver or consent relates; provided, however, that the provisions of this sentence may not be amended, modified, or supplemented except in
accordance with the provisions of the immediately preceding sentence. 
 (h)    Notices. All notices,
requests, consents and other communications or deliveries required or permitted to be provided hereunder shall be in writing, shall be sent by confirmed facsimile or electronic mail, or mailed by first-class registered or certified airmail, or
nationally recognized overnight express courier, postage prepaid, and shall be deemed given when so sent in the case of facsimile or electronic mail transmission, or when so received in the case of mail or courier, and addressed as follows: 

If to the Company, to: 

Cascadian Therapeutics, Inc. 

2601 Fourth Avenue, Suite 500 

Seattle, Washington 98121 

Attention: Julie Eastland 
 E-Mail: jeastland@cascadianrx.com 
 Facsimile: 

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

Fenwick & West LLP 

1191 Second Avenue, Floor 10 

Seattle, WA 98101 
 Attention:
Alan Smith 
 E-Mail: acsmith@fenwick.com 

Facsimilie: 
 If to a Purchaser,
to:     
 the address set forth under such Purchaser’s name on the signature page hereto; 

  
 11 








 If to any other Person who is then a registered Holder, to: 

the address of such Holder as it appears in the stock transfer books of the Company; 

or such other address as may be designated in writing hereafter, in the same manner, by such Person. 

(i)    Successors and Assigns. This Agreement shall inure to the benefit of and be binding upon the successors
and permitted assigns of each of the parties and shall inure to the benefit of each Holder. Nothing in this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors and assigns
any rights, remedies, obligations, or liabilities under or by reason of this Agreement, except as expressly provided in this Agreement. The Company may not assign its rights (except by merger or in connection with another entity acquiring all
or substantially all of the Company’s assets) or obligations hereunder without the prior written consent of all the Holders of the then outstanding Registrable Securities. Each Holder may assign its respective rights hereunder to a
transferee of the Registrable Securities; provided in each case that (i) the Holder agrees in writing with the transferee or assignee to assign such rights and related obligations under this Agreement, and for the transferee or assignee to
assume such obligations, and a copy of such agreement is furnished to the Company within a reasonable time after such assignment, (ii) the Company is, within a reasonable time after such transfer or assignment, furnished with written notice of
the name and address of such transferee or assignee and the securities with respect to which such registration rights are being transferred or assigned, (iii) at or before the time the Company received the written notice contemplated by clause
(ii) of this sentence, the transferee or assignee agrees in writing with the Company to be bound by all of the provisions contained herein and (iv) the transferee is an “accredited investor,” as that term is defined in
Rule 501 of Regulation D. 
 (j)    Execution and Counterparts. This Agreement may be executed in
two or more counterparts, each of which when so executed shall be deemed to be an original and, all of which taken together shall constitute one and the same Agreement and shall become effective when counterparts have been signed by each party and
delivered to the other party, it being understood that both parties need not sign the same counterpart. In the event that any signature is delivered by facsimile transmission or by e-mail delivery of a
“.pdf” format data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile or “.pdf” signature
were the original thereof. 
 (k)    Governing Law. All questions concerning the construction, validity,
enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of Delaware, without regard to the principles of conflicts of law thereof. With respect to any
disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, the courts in New Castle County in the State of Delaware (or in the event of federal jurisdiction, the applicable courts
located in Delaware). Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with
evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to
limit in any way any right to serve process in any other manner permitted by law. EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING
OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY. 
 (l)    Cumulative
Remedies. The remedies provided herein are cumulative and not exclusive of any other remedies provided by law 

(m)    Severability. If any term, provision, covenant or restriction of this Agreement is held by a court of
competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or invalidated,
and the parties hereto shall use their good faith reasonable efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is
hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or
unenforceable. 

  
 12 








 (n)    Headings. The headings in this Agreement are for
convenience only and shall not limit or otherwise affect the meaning hereof. 
 (o)    Independent Nature of
Purchasers’ Obligations and Rights. The obligations of each Purchaser under this Agreement are several and not joint with the obligations of any other Purchaser hereunder, and no Purchaser shall be responsible in any way
for the performance of the obligations of any other Purchaser hereunder. The decision of each Purchaser to purchase the Securities pursuant to the Transaction Documents has been made independently of any other Purchaser. Nothing contained
herein or in any other agreement or document delivered at any closing, and no action taken by any Purchaser pursuant hereto or thereto, shall be deemed to constitute the Purchasers as a partnership, an association, a joint venture or any other kind
of entity, or create a presumption that the Purchasers are in any way acting in concert with respect to such obligations or the transactions contemplated by this Agreement. Each Purchaser acknowledges that no other Purchaser has acted as agent
for such Purchaser in connection with making its investment hereunder and that no Purchaser will be acting as agent of such Purchaser in connection with monitoring its investment in the Securities or enforcing its rights under the Transaction
Documents. Each Purchaser shall be entitled to protect and enforce its rights, including, without limitation, the rights arising out of this Agreement, and it shall not be necessary for any other Purchaser to be joined as an additional party in any
Proceeding for such purpose. The Company acknowledges that each of the Purchasers has been provided with the same Registration Rights Agreement for the purpose of closing a transaction with multiple Purchasers and not because it was required or
requested to do so by any Purchaser. 
 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK] 

  
 13 








 IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date
first written above. 
  

			
	CASCADIAN THERAPEUTICS, INC.
		
	By:	 	 /s/ Scott D. Myers

	Name:	 	Scott D. Myers
	Title:	 	Chief Executive Officer


 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK] 

  
 14 








 IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date
first written above. 
  

			
	NAME OF INVESTING ENTITY
	
	  

	
	AUTHORIZED SIGNATORY
		
	By:	 	  

	Name:	 	
	Title:	 	


 
			
	
	ADDRESS FOR NOTICE
		
		 	  

		
	Street:	 	  

		
	City/State/Zip:	 	  

		
	Attention:	 	  

		
	Tel:	 	  

		
	Fax:	 	  

		
	Email:	 	  




  
 15 








 ANNEX A 

PLAN OF DISTRIBUTION 
 We are
registering shares of Common Stock issuable upon the conversion of the Shares issued to the selling stockholders to permit the resale of the shares of Common Stock by the holders of the Shares from time to time after the date of this
prospectus. We will not receive any of the proceeds from the sale by the selling stockholders of the shares of Common Stock. We will bear all fees and expenses incident to our obligation to register the shares of Common Stock. 

The selling stockholders may sell all or a portion of the shares of Common Stock (or interests in shares of Common Stock) beneficially owned
by them and offered hereby from time to time directly or through one or more underwriters, broker-dealers or agents. If the shares of Common Stock are sold through underwriters or broker-dealers, the selling stockholders will be responsible for
underwriting discounts or commissions or agent’s commissions. The shares of Common Stock may be sold on any national securities exchange or quotation service on which the securities may be listed or quoted at the time of sale, in the over-the-counter market or in private transactions otherwise than on these exchanges or systems or in the
over-the-counter market and in one or more transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of
sale, or at negotiated prices. These sales may be effected in transactions, which may involve crosses or block transactions. The selling stockholders may use any one or more of the following methods when selling shares: 

 

	 	•	 	ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers; 

  

	 	•	 	block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction; 


 

	 	•	 	purchases by a broker-dealer as principal and resale by the broker-dealer for its account; 

  

	 	•	 	an exchange distribution in accordance with the rules of the applicable exchange; 

  

	 	•	 	privately negotiated transactions; 

  

	 	•	 	settlement of short sales entered into after the effective date of the registration statement of which this prospectus is a part; 

  

	 	•	 	broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share; 

  

	 	•	 	through the writing or settlement of options or other hedging transactions, whether such options are listed on an options exchange or otherwise; 


 

	 	•	 	a combination of any such methods of sale; and 

  

	 	•	 	any other method permitted pursuant to applicable law. 

 The selling stockholders also may
resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, as permitted by that rule, or Section 4(1) under the Securities Act, if available, rather than under this
prospectus, provided that they meet the criteria and conform to the requirements of those provisions. 
 Broker-dealers engaged by the
selling stockholders may arrange for other broker-dealers to participate in sales. If the selling stockholders effect such transactions by selling shares of Common Stock to or through underwriters, broker-dealers or agents, such underwriters,
broker-dealers or agents may receive commissions in the 

  
 16 








 
form of discounts, concessions or commissions from the selling stockholders or commissions from purchasers of the shares of Common Stock for whom they may act as agent or to whom they may sell as
principal. Such commissions will be in amounts to be negotiated, but, except as set forth in a supplement to this Prospectus, in the case of an agency transaction will not be in excess of a customary brokerage commission in compliance with FINRA
Rule 2440; and in the case of a principal transaction a markup or markdown in compliance with FINRA IM-2440. 

In connection with sales of the shares of Common Stock or otherwise, the selling stockholders may enter into hedging transactions with
broker-dealers or other financial institutions, which may in turn engage in short sales of the shares of Common Stock in the course of hedging in positions they assume. The selling stockholders may also sell shares of Common Stock short and if
such short sale shall take place after the date that this Registration Statement is declared effective by the Commission, the selling stockholders may deliver shares of Common Stock covered by this prospectus to close out short positions and to
return borrowed shares in connection with such short sales. The selling stockholders may also loan or pledge shares of Common Stock to broker-dealers that in turn may sell such shares, to the extent permitted by applicable law. The selling
stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of
shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction). Notwithstanding the foregoing, the selling
stockholders have been advised that they may not use shares registered on this registration statement to cover short sales of our Common Stock made prior to the date the registration statement, of which this prospectus forms a part, has been
declared effective by the SEC. 
 The selling stockholders may, from time to time, pledge or grant a security interest in some or all of the
shares of Common Stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell shares of Common Stock from time to time pursuant to this prospectus or any amendment to
this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933, as amended, amending, if necessary, the list of selling stockholders to include the pledgee, transferee or other successors in interest as
selling stockholders under this prospectus. The selling stockholders also may transfer and donate shares of Common Stock in other circumstances in which case the transferees, donees, pledgees or other successors in interest will be the selling
beneficial owners for purposes of this prospectus. 
 The selling stockholders and any broker-dealer or agents participating in the
distribution of the shares of Common Stock may be deemed to be “underwriters” within the meaning of Section 2(11) of the Securities Act in connection with such sales. In such event, any commissions paid, or any discounts or
concessions allowed to, any such broker-dealer or agent and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. Selling Stockholders who are
“underwriters” within the meaning of Section 2(11) of the Securities Act will be subject to the applicable prospectus delivery requirements of the Securities Act including Rule 172 thereunder and may be subject to certain
statutory liabilities of, including but not limited to, Sections 11, 12 and 17 of the Securities Act and Rule 10b-5 under the Securities Exchange Act of 1934, as amended, or the Exchange Act. 

Each selling stockholder has informed the Company that it is not a registered broker-dealer and does not have any written or oral agreement or
understanding, directly or indirectly, with any person to distribute the Shares (or shares of Common Stock issuable upon conversion of the Shares). Upon the Company being notified in writing by a selling stockholder that any material
arrangement has been entered into with a broker-dealer for the sale of the shares of Common Stock through a block trade, special offering, exchange distribution or secondary distribution or a purchase by a broker or dealer, a supplement to this
prospectus will be filed, if required, pursuant to Rule 424(b) under the Securities Act, disclosing (i) the name of each such selling stockholder and of the participating broker-dealer(s), (ii) the number of shares involved,
(iii) the price at which such the shares of Common Stock were sold, (iv) the commissions paid or discounts or concessions allowed to such broker-dealer(s), where applicable, (v) that such broker-dealer(s) did not conduct any
investigation to verify the information set out or incorporated by reference in this prospectus, and (vi) other facts material to the transaction. In no event shall any broker-dealer receive fees, commissions and markups, which, in the
aggregate, would exceed eight percent (8.0%). 
 Under the securities laws of some states, the shares of Common Stock may be sold in such
states only through registered or licensed brokers or dealers. In addition, in some states the shares of Common Stock may not be sold unless such shares have been registered or qualified for sale in such state or an exemption from registration
or qualification is available and is complied with. 

  
 17 








 There can be no assurance that any selling stockholder will sell any or all of the Registrable
Securities registered pursuant to the shelf registration statement, of which this prospectus forms a part. 
 Each selling stockholder and
any other person participating in such distribution will be subject to applicable provisions of the Exchange Act and the rules and regulations thereunder, including, without limitation, to the extent applicable, Regulation M of the Exchange
Act, which may limit the timing of purchases and sales of any of the shares of Common Stock by the selling stockholder and any other participating person. To the extent applicable, Regulation M may also restrict the ability of any person
engaged in the distribution of the Common Stock to engage in market-making activities with respect to the Common Stock. All of the foregoing may affect the marketability of the Common Stock and the ability of any person or entity to engage in
market-making activities with respect to the Ordinary Shares. 
 We will pay all expenses of the registration of the Registrable Securities
pursuant to the registration rights agreement, including, without limitation, Securities and Exchange Commission filing fees and expenses of compliance with state securities or “blue sky” laws; provided, however, that each
selling stockholder will pay all underwriting discounts and selling commissions, if any and any related legal expenses incurred by it. We will indemnify the selling stockholders against certain liabilities, including some liabilities under the
Securities Act, in accordance with the registration rights agreement, or the selling stockholders will be entitled to contribution. We may be indemnified by the selling stockholders against civil liabilities, including liabilities under the
Securities Act, that may arise from any written information furnished to us by the selling stockholders specifically for use in this prospectus, in accordance with the related registration rights agreements, or we may be entitled to contribution.


  
 18 








 ANNEX B 

SELLING STOCKHOLDER NOTICE AND QUESTIONNAIRE 

The undersigned holder of Series E Convertible Preferred Stock, par value $0.0001 per share of Cascadian Therapeutics, Inc. (the
“Company”) issued concurrently with the execution of the Registration Rights Agreement, dated as of January     , 2017 (the “Agreement”), understands that the Company intends to file with the
Securities and Exchange Commission a registration statement on Form S-3 (the “Resale Registration Statement”) for the registration and the resale under Rule 415 of the Securities Act
of 1933, as amended (the “Securities Act”), of the Registrable Securities. All capitalized terms not otherwise defined herein shall have the meanings ascribed thereto in the Agreement. 

In order to sell or otherwise dispose of any Registrable Securities pursuant to the Resale Registration Statement, a holder of Registrable
Securities generally will be required to be named as a selling stockholder in the related prospectus or a supplement thereto (as so supplemented, the “Prospectus”) and deliver the Prospectus to purchasers of Registrable Securities
(including pursuant to Rule 172 under the Securities Act). Holders must complete and deliver this Notice and Questionnaire in order to be named as selling stockholders in the Prospectus. Holders of Registrable Securities who do not
complete, execute and return this Notice and Questionnaire within five (5) Trading Days following the date of the Agreement (1) will not be named as selling stockholders in the Resale Registration Statement or
the Prospectus and (2) may not use the Prospectus for resales of Registrable Securities. 
 Certain legal
consequences arise from being named as a selling stockholder in the Resale Registration Statement and the Prospectus. Holders of Registrable Securities are advised to consult their own securities law counsel regarding the consequences of being
named or not named as a selling stockholder in the Resale Registration Statement and the Prospectus. 
 NOTICE 

The undersigned holder (the “Selling Stockholder”) of Registrable Securities hereby gives notice to the Company of its
intention to sell or otherwise dispose of Registrable Securities owned by it and listed below in Item (3), unless otherwise specified in Item (3), pursuant to the Resale Registration Statement. The undersigned, by signing and returning this
Notice and Questionnaire, understands and agrees that it will be bound by the terms and conditions of this Notice and Questionnaire. 
 The
undersigned hereby provides the following information to the Company and represents and warrants that such information is accurate and complete: 

QUESTIONNAIRE 
  

	1.	Name. 

 (a) Full Legal Name of Selling Stockholder: 

(b) Full Legal Name of Registered Holder (if not the same as (a) above) through which Registrable Securities Listed in
Item 3 below are held: 
 (c) Full Legal Name of Natural Control Person (which means a natural person who directly or
indirectly alone or with others has power to vote or dispose of the securities covered by the questionnaire): 

  
 19 









	2.	Address for Notices to Selling Stockholder: 

 Telephone: 

Fax: 
 Contact Person: 

E-mail address of Contact Person: 
  

	3.	Beneficial Ownership of Registrable Securities: 

 (a) Type and Number of
Registrable Securities beneficially owned: 
 (b) Number of shares of Common Stock to be registered pursuant to this Notice
for resale: 
  

	4.	Broker-Dealer Status: 

 (a) Are you a broker-dealer? 

Yes  ☐            No  ☐ 

(b) If “yes” to Section 4(a), did you receive your Registrable Securities as compensation for investment
banking services to the Company? 

Yes  ☐            No  ☐ 

Note: If no, the Commission’s staff has indicated that you should be identified as an underwriter in the Registration Statement. 

(c) Are you an affiliate of a broker-dealer? 

Yes  ☐            No  ☐ 

Note: If yes, provide a narrative explanation below: 

(c) If you are an affiliate of a broker-dealer, do you certify that you bought the Registrable Securities in the ordinary
course of business, and at the time of the purchase of the Registrable Securities to be resold, you had no agreements or understandings, directly or indirectly, with any person to distribute the Registrable Securities? 

Yes  ☐            No  ☐ 

Note: If no, the Commission’s staff has indicated that you should be identified as an underwriter in the Registration
Statement. 
  

	5.	Beneficial Ownership of Other Securities of the Company Owned by the Selling Stockholder. 


Except as set forth below in this Item 5, the undersigned is not the beneficial or registered owner of any securities of the Company other
than the Registrable Securities listed above in Item 3. 

  
 20 








 Type and amount of other securities beneficially owned: 

 

	6.	Relationships with the Company: 

 Except as set forth below, neither the undersigned
nor any of its affiliates, officers, directors or principal equity holders (owners of 5% of more of the equity securities of the undersigned) has held any position or office or has had any other material relationship with the Company (or its
predecessors or affiliates) during the past three years. 
 State any exceptions here: 

 

	7.	Plan of Distribution: 

 The undersigned has reviewed the form of Plan of Distribution
attached as Annex A to the Agreement, and hereby confirms that, except as set forth below, the information contained therein regarding the undersigned and its plan of distribution is correct and complete. 

State any exceptions here: 

*********** 
 The undersigned agrees to promptly
notify the Company of any inaccuracies or changes in the information provided herein that may occur subsequent to the date hereof and prior to the effective date of any applicable Resale Registration Statement. All notices hereunder and pursuant to
the Agreement shall be made in writing, by hand delivery, confirmed or facsimile transmission, electronic transmission, first-class mail or air courier guaranteeing overnight delivery at the address set forth below. In the absence of any such
notification, the Company shall be entitled to continue to rely on the accuracy of the information in this Notice and Questionnaire. 
 By signing below,
the undersigned consents to the disclosure of the information contained herein in its answers to Items (1) through (7) above and the inclusion of such information in the Resale Registration Statement and the Prospectus. The
undersigned understands that such information will be relied upon by the Company in connection with the preparation or amendment of any such Registration Statement and the Prospectus. 

By signing below, the undersigned acknowledges that it understands its obligation to comply, and agrees that it will comply, with the provisions of the
Exchange Act and the rules and regulations thereunder, particularly Regulation M in connection with any offering of Registrable Securities pursuant to the Resale Registration Statement. The undersigned also acknowledges that it understands
that the answers to this Questionnaire are furnished for use in connection with Registration Statements filed pursuant to the Agreement and any amendments or supplements thereto filed with the Commission pursuant to the Securities Act. 

The undersigned hereby acknowledges and is advised of the following Interpretation A.65 of the July 1997 SEC Manual of Publicly Available Telephone
Interpretations regarding short selling: 
 “An Issuer filed a Form S-3 registration statement for a
secondary offering of common stock which is not yet effective. One of the selling stockholders wanted to do a short sale of common stock “against the box” and cover the short sale with registered shares after the effective
date. The issuer was advised that the short sale could not be made before the registration statement become effective, because the shares underlying the short sale are deemed to be sold at the time such sale is made. There would,
therefore, be a violation of Section 5 if the shares were effectively sold prior to the effective date.” 
 By returning this Questionnaire,
the undersigned will be deemed to be aware of the foregoing interpretation. 

  
 21 








 I confirm that, to the best of my knowledge and belief, the foregoing statements (including without limitation
the answers to this Questionnaire) are correct. 
 IN WITNESS WHEREOF the undersigned, by authority duly given, has caused this Questionnaire to be executed
and delivered either in person or by its duly authorized agent. 
  

									
	Dated:	 	  
	 		 	    Beneficial Owner:	 	  



									
					
		 		 		 	By:	 	  

		 		 		 	Name:	 	
		 		 		 	Title:	 	

 PLEASE FAX A COPY OF THE COMPLETED AND EXECUTED NOTICE AND QUESTIONNAIRE, AND RETURN THE ORIGINAL BY OVERNIGHT MAIL, TO:

 Cascadian Therapeutics, Inc. 

[ADDRESS AND CONTACT] 

  
 22