Initial results are expected in 2H 2022

NEW YORK, NY and SAN DIEGO, CA, USA I September 13, 2021 I Zentalis Pharmaceuticals, Inc. (Nasdaq: ZNTL), a clinical-stage biopharmaceutical company focused on discovering and developing small molecule therapeutics targeting fundamental biological pathways of cancers, today announced that the first patient has been dosed in the Phase 1/2 trial of ZN-c3, the Company’s oral WEE1 inhibitor product candidate, in combination with gemcitabine, a chemotherapy used to treat certain malignant tumors, in pediatric and adult patients with relapsed or refractory osteosarcoma.

“We are thrilled to expand our ZN-c3 program with the initiation of a fourth clinical trial for this candidate, underscoring ZN-c3’s potential versatility across a broad range of solid tumors,” commented Dr. Anthony Sun, Chairman and Chief Executive Officer of Zentalis. “Relapsed or refractory patients with osteosarcoma, a rare type of bone cancer, have an extremely poor prognosis, reinforcing the need for novel treatment regimens to combat this highly aggressive disease. With over 50% of osteosarcomas having a mutation in TP53 – potentially resulting in chemoresistance – we believe that inhibiting the DNA damage response protein WEE1 could enhance the efficacy of gemcitabine in this pre-treated population. We are eager to conduct this seminal study evaluating this combination’s clinical safety and efficacy and look forward to reporting initial results from this trial in the second half of 2022.”

Zentalis recently received orphan drug and rare pediatric disease designations from the U.S. Food and Drug Administration for pediatric osteosarcoma. If ZN-c3 were to obtain approval for the designated indication, it could potentially be eligible for a rare pediatric disease priority voucher upon approval.

The Phase 1/2 trial (ZN-c3-003) is a dose escalation and dose expansion study, evaluating the clinical activity, safety, pharmacodynamics and pharmacokinetics of ZN-c3 in combination with gemcitabine in relapsed or refractory osteosarcoma. The primary efficacy endpoint is event-free survival (EFS) at 18 weeks per RECIST criteria. Secondary endpoints include EFS per RECIST, median overall survival and overall survival at 12 months. More information about the trial is available at NCT04833582.

About Osteosarcoma

Osteosarcoma, while rare, is the most common type of bone cancer and is often associated with a high degree of malignancy, early metastasis, rapid progression, and poor prognosis. This cancer occurs primarily in children, teens and young adults ranging from 10 to 30 years old. The risk of diagnosis decreases in adulthood, but rises again in older adults usually over the age of 60. Approximately 1,000 new cases of osteosarcoma are diagnosed in the United States each year. Treatment typically includes a combination of surgery and chemotherapy, with chemotherapy administered before and after surgery to help lower the risk of relapse. Even though curative therapy is available for the primary tumor, long-term outcomes for osteosarcoma patients continue to be impacted by metastatic progression. In addition, over 50% of osteosarcomas have a mutation in TP53 which portends a poorer prognosis and implies chemoresistance. As no substantive improvements in long-term outcomes have occurred for more than three decades, there remains an urgent need for improved therapies to prevent or treat metastatic disease.

About ZN-c3

ZN-c3 is a potentially first-in-class and best-in-class oral inhibitor of WEE1 in development for the treatment of advanced solid tumors. The inhibition of WEE1, a DNA damage response protein, aims to generate sufficient DNA damage in cancer cells, causing cell death, thereby preventing tumor growth and potentially causing tumor regression. ZN-c3 has broad potential as a monotherapy and in combination and we are currently evaluating this candidate in several ongoing and planned studies, including two potentially registrational monotherapy trials in USC and a biomarker-driven setting, as well as combination studies such as with chemotherapy in patients with advanced ovarian cancer. We also recently received orphan drug and rare pediatric disease designations from the FDA for pediatric osteosarcoma and have initiated a Phase 1/2 trial in combination with chemotherapy.

About Zentalis Pharmaceuticals

Zentalis Pharmaceuticals, Inc. is a clinical-stage biopharmaceutical company focused on discovering and developing small molecule therapeutics targeting fundamental biological pathways of cancers. The Company is developing a broad pipeline of potentially best-in-class oncology candidates, all internally discovered, which include ZN-c3, a WEE1 inhibitor for advanced solid tumors, ZN-c5, an oral selective estrogen receptor degrader (SERD) for ER+/HER2- breast cancer, ZN-d5, a BCL-2 inhibitor for hematologic malignancies, and ZN-e4, an EGFR inhibitor for non-small cell lung carcinoma (NSCLC). Zentalis has licensed ZN-c3, ZN-c5 and ZN-d5 to its joint venture, Zentera Therapeutics, to develop and commercialize these candidates in China. Zentalis has operations in both New York and San Diego.

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SOURCE: Zenalis Pharmaceuticals