UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 28, 2019

Principia Biopharma Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware	001-38653	26-3487603
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)
220 East Grand Avenue, South San Francisco, California		94080
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s Telephone Number, Including Area Code: (650) 416-7700

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events

Results of the Believe-PV proof-of-concept clinical trial of PRN1008 in pemphigus were presented today, February 28, 2019, at the Medical Dermatology Society (MDS) Annual Meeting. The meeting was held in Washington, D.C. PRN1008 achieved Control of Disease Activity (CDA) on Low Dose Corticosteroids (LDCS), in 7/26 patients (27%), 14/26 (54%) and 19/26 (73%) by 2, 4 and 12 weeks, respectively. Complete response (CR) on LDCS at any time during the trial was achieved by 6/24 (25%) patients completing the study. Treatment-related adverse events reported by ³ 10% of patients were Grade 1/2 nausea (15%), headache (11%) and abdominal pain (upper) (11%).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	Company Name
Date: February 28, 2019	By:	/s/ Christopher Y. Chai
		Christopher Y. Chai
		Chief Financial Officer