Phoenix Molecular Designs (PhoenixMD) has initiated Phase 2 clinical trials (Dauntless-1) for PMD-026, a first-in-class pan-RSK inhibitor, in combination with fulvestrant. The trial targets patients with locally advanced or metastatic HR+/HER2-/RSK2-high breast cancer who have progressed after CDK4/6 inhibitor treatment. This approach aims to address CDK4/6 inhibitor resistance, a significant challenge in treating this type of breast cancer.
This trial is a critical step toward improving outcomes for patients with advanced breast cancer who have limited effective treatment options after developing CDK4/6 inhibitor resistance. Fulvestrant, a standard second-line therapy, often provides only short-term benefit. Preclinical data suggests that combining PMD-026 with fulvestrant could significantly extend the duration of response, offering a new therapeutic strategy for this patient population. Focusing on RSK2-high patients allows for a targeted approach, potentially increasing the likelihood of success.
The Phase 2 trial builds upon promising Phase 1/1b monotherapy results where PMD-026 demonstrated a median progression-free survival of 4.8 months in RSK2-high patients compared to 1.3 months in RSK2-low patients who had received limited prior therapies. Importantly, PMD-026 was well-tolerated without common side effects like peripheral neuropathy, hair loss, or hyperglycemia. These factors, along with the preclinical synergy with fulvestrant, support the rationale for the combination therapy approach.
The initiation of the Dauntless-1 trial represents a significant advancement in the development of PMD-026. Positive Phase 2 results could lead to a new treatment option for patients with advanced breast cancer who have developed resistance to CDK4/6 inhibitors, ultimately changing the treatment landscape for this challenging disease. This could also establish PMD-026 as a key player in the precision oncology field and potentially pave the way for its use in other cancer types.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
