Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): May 15, 2019



Constellation Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)




Delaware   001-38584   26-1741721

(State or Other Jurisdiction

of Incorporation)



File Number)


(IRS Employer

Identification No.)


215 First Street, Suite 200

Cambridge, Massachusetts

(Address of Principal Executive Offices)   (Zip Code)

Registrant’s telephone number, including area code: (617) 714-0555

Not applicable

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



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

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


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Trading Symbols(s)


Name of each exchange on which

Common Stock, par value $0.0001   CNST   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 ☒

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 7.01

Regulation FD Disclosure.

On May 15, 2019, Abstract #260583, A Phase 2 Study of CPI-0610, a Bromodomain and Extraterminal Protein Inhibitor (BETi) alone or with Ruxolitinib (RUX), in Patients with Myelofibrosis (MF), which had been submitted by Constellation Pharmaceuticals, Inc. to the American Society for Clinical Oncology (ASCO) in connection with the 2019 ASCO Annual Meeting on May 31-June 4, 2019 in Chicago, Illinois, was published by ASCO. A copy of the abstract is attached hereto as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

The information in this Item 7.01, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933 or the Exchange Act, except as expressly set forth by specific reference in such a filing.


Item 9.01

Financial Statements and Exhibits.

(d) Exhibits


99.1    Abstract #260583, ASCO Annual Meeting, May 31-June 4, 2019 | Chicago, Illinois. A Phase 2 Study of CPI-0610, a Bromodomain and Extraterminal Protein Inhibitor (BETi) alone or with Ruxolitinib (RUX), in Patients with Myelofibrosis (MF) (furnished herewith)


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


Date: May 15, 2019     By:   /s/ Jigar Raythatha

Name: Jigar Raythatha

Title: Chief Executive Officer


Exhibit 99.1

Abstract #260583

2019 ASCO Annual Meeting

May 31-June 4, 2019 | Chicago, Illinois

A Phase 2 Study of CPI-0610, a Bromodomain and Extraterminal Protein Inhibitor (BETi) alone or with Ruxolitinib (RUX), in Patients with Myelofibrosis (MF)

Background: BETi have been shown to regulate NF-KB, MYC, BCL2, and TGF-ß signaling, important drivers of marrow fibrosis. Preclinical studies have suggested that combined BETi and JAK2 inhibition synergistically reduce MF-related splenomegaly, bone marrow fibrosis and the malignant allele burden (Kleppe, 2018). CPI-0610 is a selective and potent oral BETi, being evaluated in the first study of a BETi in MF

Methods: Phase 2 trial with 3 arms: CPI-0610 monotherapy (Arm 1) or RUX + CPI-0610 “add-on” (Arm 2) in pts who have progressed/ had an inadequate response to RUX, or CPI-0610 + RUX in JAK inhibitor-naïve pts with anemia (Arm 3). Arms 1 and 2 are stratified: transfusion dependence (TD) yes: A/no: B. The primary objectives are to evaluate the effect of CPI-0610 on transfusion dependence (TD, 1A and 2A) and spleen volume (1B, 2B and 3). A Simon two-stage design: if 2 responses are seen will advance to the 2nd stage

Results: 4 pts enrolled in Arm 1, 14 pts in Arm 2, no pts accrued to Arm 3 yet. Median age: 69 years (46-83), gender: 9 male pts; 11pts received =1 prior therapy besides RUX. JAK2/MPL/CALR mutations: 17/18 pts, =3 mutations: 10 pts, ASXL1 mutations: 11 (61%) pts. Hemoglobin <10 g/dL at baseline: 11 (61%) pts. 6 pts received ³ 24 weeks of CPI-0610 treatment at this analysis. 2 TD pts in Arm 2 became transfusion independence, both remain on treatment free of transfusions. Hgb increase of ³1.5 g/dL from baseline was observed with successive cycles of therapy in anemic pts: 2/2 pts in Arm 1(100%) and 3/9 pts in Arm 2, (33%). Spleen volume reduction, by MRI (6-44%) was observed in all 10 evaluable pts irrespective of their driver mutation. Symptom improvement and reductions of cytokine levels were observed. In Arm 1: 2/2 evaluable pts had marrow fibrosis improvement with Hgb increase; additionally, thrombocytosis resolved in 2/2 pts (baseline ³791

103/uL). Most common adverse events were mild diarrhea, nausea/vomiting; and reversible and non-cumulative thrombocytopenia

Conclusions: CPI-0610 is a well-tolerated, and an effective therapeutic agent for the treatment of MF. Collectively, these data indicate that CPI-0610 +/- RUX might have disease modifying effects. Updated data will be provided

Authors: Marina Kremyanskaya MD, PhD1, Ronald Hoffman MD2, John Mascarenhas MD3, Prithviraj Bose MD4, Vikas Gupta MD5, Gary J. Schiller MD6, Elena Liew MD7, Claudia Lebedinsky MD8, Adrian Mario Senderowicz MD8, Jennifer Mertz PhD8, Patrick Trojer PhD8, Srdan Verstovsek MD, PhD4

1 Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA; 2 Tisch Cancer Institute, Department of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, USA; 3Division of Hematology/Medical Oncology/Pathology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai; Myeloproliferative Neoplasm Research Consortium (MPN-RC), New York, USA; 4 Department of Leukemia, M.D. Anderson Cancer Center, Houston, TX, USA; 5 Princess Margaret Hospital, Toronto, Canada, 6 University of California, Los Angeles, USA; 7 University of Alberta Hospital, Alberta, Canada; 8 Constellation Pharmaceuticals, Cambridge, MA, USA