UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G/A

Under the Securities Exchange Act of 1934

(Amendment No. 4)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 046513107

⁽¹⁾ Redmile Group, LLC’s beneficial ownership of the Issuer’s common stock (“Common Stock”) is comprised of 4,648,570 shares of Common Stock owned by certain private investment vehicles and/or separately managed accounts managed by Redmile Group, LLC, which shares of Common Stock may be deemed beneficially owned by Redmile Group, LLC as investment manager of such private investment vehicles and/or separately managed accounts. The reported securities may also be deemed beneficially owned by Jeremy C. Green as the principal of Redmile Group, LLC. Redmile Group, LLC and Mr. Green each disclaim beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any. Subject to the Beneficial Ownership Blocker (as defined below), Redmile Group, LLC may also be deemed to beneficially own 2,945,026 shares of Common Stock issuable upon exercise of certain Pre-Funded Warrants to Purchase Common Stock (the “Warrants”). Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of any Warrant, and a holder of a Warrant does not have the right to exercise any portion of the Warrant held by such holder, to the extent that, after giving effect to the attempted exercise set forth in a notice of exercise, such holder, together with such holder’s affiliates and any other person whose beneficial ownership of Common Stock would be aggregated with such holder’s for the purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the applicable regulations of the Securities and Exchange Commission (the “SEC”), including any “group” of which such holder is a member, would beneficially own a number of shares of Common Stock in excess of the Beneficial Ownership Limitation (the “Beneficial Ownership Blocker”). The “Beneficial Ownership Limitation” is 9.99% of the shares of Common Stock then issued and outstanding, which percentage may be changed at a holder’s election upon 61 days’ notice to the Issuer. The 5,494,109 shares of Common Stock reported as beneficially owned by Redmile Group, LLC in this Schedule 13G represents 9.99% of the outstanding shares of Common Stock (calculated in accordance with footnote (2) below).

⁽²⁾ Percentage based on: (i) 54,150,553 shares of Common Stock outstanding as of October 31, 2019, as reported by the Issuer in its Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2019 filed with the SEC on November 7, 2019 (the “Form 10-Q”), plus (ii) 845,539 shares of Common Stock issuable upon exercise of certain of the Warrants, which, due to the Beneficial Ownership Limitation, is the maximum number of shares that could be issued upon exercise of the Warrants as of October 31, 2019.

CUSIP No. 046513107

⁽³⁾ Jeremy C. Green’s beneficial ownership of Common Stock is comprised of 4,648,570 shares of Common Stock owned by certain private investment vehicles and/or separately managed accounts managed by Redmile Group, LLC, which shares of Common Stock may be deemed beneficially owned by Redmile Group, LLC as investment manager of such private investment vehicles and/or separately managed accounts. The reported securities may also be deemed beneficially owned by Jeremy C. Green as the principal of Redmile Group, LLC. Redmile Group, LLC and Mr. Green each disclaim beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any. Subject to the Beneficial Ownership Blocker, Mr. Green may also be deemed to beneficially own 2,945,026 shares of Common Stock issuable upon exercise of the Warrants. Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of any Warrant, and a holder of a Warrant does not have the right to exercise any portion of the Warrant held by such holder, if the Beneficial Ownership Blocker applies. The 5,494,109 shares of Common Stock reported as beneficially owned by Redmile Group, LLC in this Schedule 13G represents 9.99% of the outstanding shares of Common Stock (calculated in accordance with footnote (4) below).

⁽⁴⁾ Percentage based on: (i) 54,150,553 shares of Common Stock outstanding as of October 31, 2019, as reported by the Issuer in Form 10-Q, plus (ii) 845,539 shares of Common Stock issuable upon exercise of certain of the Warrants, which, due to the Beneficial Ownership Limitation, is the maximum number of shares that could be issued upon exercise of the Warrants as of October 31, 2019.

Item 1.

Item 2.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 14, 2020

Exhibit A

Redmile Group, LLC is the relevant entity for which Jeremy C. Green may be considered a control person.