INVESTORS
Sierra Holds Analyst & Investor Event for SRA737

- Sierra management and distinguished oncologists Professor Johann de Bono and Dr. Rebecca Kristeleit discuss clinical findings and possible next steps for SRA737 -
- Sierra reported SRA737 activity, including 30% response rate for SRA737+LDG in anogenital cancer, in preliminary Phase 1/2 data presented at the 2019 ASCO Annual Meeting –
- Regulatory clarity for Sierra's lead asset momelotinib anticipated in the near-term -

VANCOUVER, June 3, 2019 /CNW/ - Sierra Oncology, Inc. (SRRA), a late-stage drug development company focused on advancing targeted therapeutics for the treatment of patients with significant unmet needs in hematology and oncology, is holding an analyst and investor event today featuring distinguished oncologists Professor Johann de Bono and Dr. Rebecca Kristeleit, to discuss clinical findings and possible next steps for its oral, highly selective Chk1 inhibitor, SRA737.

On Saturday, June 1st, Sierra reported positive preliminary clinical data from its two first-in-human Phase 1/2 studies of SRA737, as monotherapy and as SRA737+LDG (low dose gemcitabine), at the 2019 Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago. Detailed results were issued by press release on June 1st and are available on Sierra's website at www.sierraoncology.com. Anti-cancer activity was demonstrated across multiple indications and genetic contexts, with SRA737+LDG specifically achieving a notable 30% response rate in anogenital cancer patients, an indication for which the second line metastatic setting represents a significant unmet medical need with no approved therapies and very poor life expectancy. Additionally, subjects whose tumors harbored FA/BRCA gene network mutations displayed favorable outcomes, including an Overall Response Rate = 25% and Disease Control Rate = 81%.

"These positive data indicate that SRA737 is a demonstrably active anti-cancer drug that we believe warrants further development. The initial efficacy and favorable tolerability profile described at ASCO also enables several potentially promising opportunities for its development in combination with other therapeutics, in particular with PARP inhibitors and immunotherapy agents where we have previously reported robust preclinical efficacy data," said Dr. Nick Glover, President and CEO of Sierra Oncology. "We also look forward to announcing regulatory clarity for our lead asset momelotinib in the near-term. We have been holding productive discussions with regulators and continue to prepare for a Phase 3 clinical trial intended to potentially support its registration. Given momelotinib is our lead drug candidate and highest priority, we will be exploring options to enable the continued advancement of SRA737 in the context of our emerging pipeline."

SRA737 Analyst & Investor Event
The company is hosting an Analyst and Investor Event on Monday, June 3, 2019, to discuss these clinical findings and potential next steps in the development strategy for SRA737+LDG.

Date and Time: June 3, 2019, 6:00 – 7:00 am CT

Location: History event room, Marriot Marquis Hotel, 2121 S Prairie Ave, Chicago, Illinois.

The event will feature presentations by two distinguished oncologists:

  • Professor Johann de Bono, Regius Professor of Cancer Research, Head of the Division of Clinical Studies and Professor in Experimental Cancer Medicine at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, will discuss the critical role of Chk1 in tumor cell survival during replication stress, as well as describe potential opportunities to combine SRA737 with other therapeutic modalities including PARP inhibitors and immunotherapy agents.
  • Dr. Rebecca Kristeleit, Clinical Senior Lecturer and Honorary Consultant Medical Oncologist at University College London (UCL) Cancer Institute & UCLH Dept. of Oncology, a leading expert in gynecological malignancies, will discuss her clinical experience with SRA737+LDG, and potential development opportunities for this novel combination in the treatment of anogenital cancers.

Event registration and webcast information are available through the Sierra Oncology website at www.sierraoncology.com. An archive of the presentation will be accessible after the event through the Sierra Oncology website.

About SRA737 and SRA737+LDG
SRA737 is a potent, highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key regulator of cell cycle progression and the DNA Damage Response (DDR). Tumors with high levels of replication stress become reliant on Chk1 to mitigate the potentially catastrophic consequences of excess genomic instability.

Intrinsic sources of replication stress can include genetic alterations in tumor suppressors, oncogenes or DNA Damage Repair genes. Tumors harboring defects in these gene classes are hypothesized to have higher levels of intrinsic replication stress due to dysregulated cell cycle control, increased proliferation demands and increased genomic instability. SRA737+LDG is a novel drug combination, where non-cytotoxic low dose gemcitabine (LDG) acts as a potent extrinsic inducer of replication stress.

Sierra Oncology retains the global commercialization rights to SRA737.

About Sierra Oncology
Sierra Oncology is a clinical stage drug development company advancing targeted therapeutics for the treatment of patients with unmet medical needs in hematology and oncology. Our lead drug candidate, momelotinib, is a potent, selective and orally bioavailable JAK1, JAK2 and ACVR1 inhibitor that has been investigated in two completed Phase 3 trials for the treatment of myelofibrosis and has demonstrated a potentially differentiated therapeutic profile encompassing anemia-related benefits, as well as achieving substantive splenic volume reduction and constitutional symptom control.

Sierra Oncology is also advancing SRA737 and SRA141. SRA737 is a potent, highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key regulator of cell cycle progression and the DNA Damage Response (DDR). SRA141 is a potent, selective, orally bioavailable small molecule inhibitor of Cell division cycle 7 kinase (Cdc7). Cdc7 is a key regulator of DNA replication and is involved in the DDR network, making it a compelling emerging target for the potential treatment of a broad range of tumor types.

For more information, please visit www.sierraoncology.com.

Cautionary Note on Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding Sierra Oncology's expectations from current data, anticipated clinical development activities, time of regulatory communications and potential benefits of Sierra Oncology's product candidates. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. These statements are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and assumptions that could cause actual results to differ materially from those described in the forward-looking statements. Such forward-looking statements are subject to risks and uncertainties, including, among others, the risk that Sierra Oncology may be unable to successfully develop and commercialize product candidates, product candidates may not demonstrate safety and efficacy or otherwise produce positive results, Sierra Oncology may experience delays in the preclinical and anticipated clinical development of its product candidates, Sierra Oncology may be unable to acquire additional assets to build a pipeline of additional product candidates, Sierra Oncology's third-party manufacturers may cause its supply of materials to become limited or interrupted or fail to be of satisfactory quantity or quality, Sierra Oncology's cash resources may be insufficient to fund its current operating plans and it may be unable to raise additional capital when needed, Sierra Oncology may be unable to obtain and enforce intellectual property protection for its technologies and product candidates and the other factors described under the heading "Risk Factors" set forth in Sierra Oncology's filings with the Securities and Exchange Commission from time to time. Sierra Oncology undertakes no obligation to update the forward-looking statements contained herein or to reflect events or circumstances occurring after the date hereof, other than as may be required by applicable law.

SOURCE Sierra Oncology

For further information: James Smith, Vice President, Corporate Affairs, Sierra Oncology, 604.558.6536, investors@sierraoncology.com