false 0001718852 0001718852 2022-07-26 2022-07-26





Washington, D.C. 20549







Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): July 26, 2022




(Exact name of registrant as specified in its charter)




Delaware   001-40187   81-4282653

(State or other jurisdiction of

incorporation or organization)



File Number)


(I.R.S. Employer

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3050 Science Park Road

San Diego, California 92121

(Address of principal executive offices) (Zip Code)

(858) 422-4300

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



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Securities registered pursuant to Section 12(b) of the Act:


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Common Stock, par value $0.0001 per share   RXDX   The Nasdaq Global Select Market

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  

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Item 8.01.

Other Events.

On July 26, 2022, Prometheus Biosciences, Inc. (“Prometheus” or the “Company”) held its previously announced R&D Day focused on the Company’s second program, PR600, and unveiled its corresponding clinical candidate, PRA052, an anti-CD30L monoclonal antibody. The CD30L-CD30 co-stimulatory pathway has been implicated in inflammatory bowel disease (“IBD”) by genetic, preclinical, and human translational data. In preclinical studies, CD30L antagonism was observed to improve multiple animal models of colitis. PRA052 is designed to have high affinity and specificity for CD30L and to block both membrane-bound and soluble CD30L.

The Company plans to file an investigational new drug application (“IND”) for PRA052 in the third quarter of 2022 and expects to advance PRA052 into a Phase 1 single ascending dose/multiple ascending dose clinical trial in normal healthy volunteers in the fourth quarter of 2022. The Company also announced that it is developing a proprietary companion diagnostic genetic test for PRA052 that incorporates functional genomics from IBD patient cohorts to identify patients that are more likely to respond to CD30L inhibition.

Forward Looking Statements

Prometheus cautions readers that statements contained in this report regarding matters that are not historical facts are forward-looking statements. These statements are based on the company’s current beliefs and expectations. Such forward-looking statements include, but are not limited to statements regarding: the timing of filing the IND and initiating a Phase 1 clinical trial for PRA052; and the potential for PRA052 to improve IBD symptoms, including colitis. The inclusion of forward-looking statements should not be regarded as a representation by Prometheus that any of our plans will be achieved. Actual results may differ from those set forth in this report due to the risks and uncertainties inherent in our business, including, without limitation: our approach to the discovery and development of precision medicines based on Prometheus360TM is unproven, and we do not know whether we will be able to develop any therapeutics or companion diagnostic products of commercial value; potential delays in the commencement, enrollment and completion of clinical trials and preclinical studies; we are early in our development efforts and have only one product candidate in early clinical development and all of our other development programs are in the preclinical or discovery stage; disruption to our operations from the COVID-19 pandemic; the success of clinical trials and preclinical studies for our product candidates; the results of preclinical studies and early clinical trials are not necessarily predictive of future results; our dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; unexpected adverse side effects or inadequate efficacy of our product candidates that may limit their development, regulatory approval and/or commercialization, or may result in recalls or product liability claims; our ability to develop companion diagnostics for our therapeutic product candidates; regulatory developments in the United States and foreign countries, including acceptance of INDs and similar foreign regulatory filings and the proposed design of future clinical trials;; and other risks described in our filings with the SEC, including under the heading “Risk Factors” in our Form 10-K filed with the SEC on March 9, 2022 and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.


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 hereunto duly authorized.


Date: July 26, 2022     By:  

/s/ Timothy K. Andrews

      Timothy K. Andrews
      General Counsel and Secretary