Kymera Therapeutics to Present New Clinical Data from Ongoing Phase 1 Trial of MDM2 Degrader KT-253 at ASCO Annual Meeting

Abstract released today highlights safety, pharmacodynamic and clinical response data with additional data to be presented in a poster session on June 1, 2024

KT-253 Phase 1 study ongoing with additional data expected in the second half of 2024

WATERTOWN, Mass., May 23, 2024 (GLOBE NEWSWIRE) -- Kymera Therapeutics, Inc. (NASDAQ: KYMR), a clinical-stage biopharmaceutical company advancing a new class of small molecule medicines using targeted protein degradation (TPD), today announced new clinical data for KT-253, a first-in-class MDM2 degrader, from its ongoing Phase 1 dose escalation trial will be presented at the American Society of Clinical Oncology (ASCO) Annual Meeting, taking place from May 31 – June 4, 2024, in Chicago, Illinois. Results released in an ASCO abstract today include a data cut-off of January 26, 2024.

“We continue to see encouraging data from the trial’s dose escalation phase demonstrating potent upregulation of p53 biomarkers and signs of antitumor activity in patients. Results have included objective responses in liquid and solid tumors, at doses that are well tolerated without the traditional hematological toxicity seen with small molecule inhibitors,” said Jared Gollob, MD, Chief Medical Officer, Kymera Therapeutics. “We look forward to sharing the full Phase 1 data set, as well as our biomarker-based patient selection strategy and guidance on the program’s next development steps, later this year.”

Highlights of the KT-253 Clinical Abstract

The abstract reported Phase 1 data from 18 patients including 13 patients in Arm A (solid tumors and lymphomas) at dose levels (DL) 1-4, and 5 patients in Arm B (high grade myeloid malignancies) at DL1-2 as of January 26, 2024. The most common solid tumor types were Merkel cell carcinoma (MCC) in 3 patients, adenoid cystic carcinoma (ACC) in 2 patients, and uveal melanoma in 2 patients. Highlights include:

• Disease Response Assessments:
  • Arm A: One partial response confirmed in a MCC patient in DL1. Additionally, 3 stable diseases were reported for patients with fibromyxoid sarcoma, ACC, and renal cell cancer in DL1-3, respectively.
  • Arm B: One confirmed complete response in DL2 and one confirmed partial response in DL1, both in patients with post-myeloproliferative neoplasm (MPN) acute myeloid leukemia (AML). 
• Pharmacodynamic (PD) data from Arm A (DL1-4) and Arm B (DL1-2) demonstrated rapid upregulation of plasma GDF-15 protein and upregulation of CDKN1A and PHLDA3 mRNA levels in blood. KT-253 demonstrated dose-dependent increase in plasma exposure with levels approximating projected efficacious doses.
• KT-253 was generally well-tolerated with the most common adverse events (AEs) including nausea, fatigue, headache, and vomiting. There was 1 dose-limiting toxicity (DLT) of AEs leading to discontinuation that included Grade 2 nausea and fatigue in Arm A DL4. There were no neutropenia or thrombocytopenia AEs in either Arm. KT-253 related serious adverse events (SAEs) included Grade 3 hypotension in a patient with decreased oral intake in Arm A DL1.