Core Insights - Immutep Limited is set to present new data from the AIPAC-003 trial at the 2025 San Antonio Breast Cancer Symposium, highlighting its late-stage immunotherapy targeting cancer and autoimmune diseases [1] Study Overview - The Phase II AIPAC-003 trial involved 66 female participants with HR+ and HER2-negative/HER2-low metastatic breast cancer resistant to endocrine therapy or metastatic triple-negative breast cancer not eligible for PD-(L)1 therapy [2] - Participants were randomized to receive either 30 mg or 90 mg of eftilagimod alfa in combination with paclitaxel to determine the optimal biological dose [2] Efficacy Results - The study reported strong objective response rates (ORR) of 41.9% for the 30 mg dose and 48.5% for the 90 mg dose, with disease control rates (DCR) of 87.1% and 78.8%, respectively [3] - Time to onset of response was similar at 2.0 months for the 30 mg dose and 1.9 months for the 90 mg dose [3] Pharmacodynamic Response - Both dosing levels showed significant increases in immune activation biomarkers, including absolute-lymphocyte count and interferon-gamma, aligning with the mechanism of action of eftilagimod alfa [4] Clinical Implications - The study's findings support the selection of 30 mg as the optimal biological dose, which is crucial for meeting FDA's Project Optimus requirements and advancing Immutep's oncology pipeline [6] - The ongoing Phase III TACTI-004 trial will evaluate eftilagimod alfa in combination with KEYTRUDA and chemotherapy for advanced or metastatic non-small cell lung cancer [6] Presentation Details - The presentation at SABCS 2025 will be led by Dr. Nuhad Ibrahim and will focus on the optimal biological dose of eftilagimod alfa in metastatic breast cancer patients [7][8]

Financial Data and Key Metrics Changes - The company ended Q1 2025 with $102.3 million in cash and cash equivalents, expecting to extend its cash runway into mid-2026 due to a restructuring plan [18] - Net cash used in operating activities for Q1 2025 was $29.3 million [18] - Collaboration revenue for Q1 2025 was $2.8 million, down from $9.2 million in the same period in 2024, primarily due to reduced revenue from collaborations with J&J and Merck KGaA [18][19] - Net loss for Q1 2025 was $24.1 million, compared to a net loss of $19.3 million in Q1 2024 [20] Business Line Data and Key Metrics Changes - Research and development expenses for Q1 2025 were $18.3 million, slightly down from $18.7 million in Q1 2024, with a portion attributed to non-cash stock-based compensation [19] - General and administrative expenses decreased to $8.9 million in Q1 2025 from $11.6 million in Q1 2024, reflecting lower consulting fees and employee compensation costs [19][20] Market Data and Key Metrics Changes - The company is focusing on the triple-negative breast cancer (TNBC) market, with ongoing clinical trials for its product EMILY, which targets B7-H4 expression [7][9] - The global TNBC revenues for Trodelvy are projected to exceed $1 billion in 2025, indicating a growing market opportunity [16] Company Strategy and Development Direction - Mersana announced a strategic restructuring plan that includes workforce reduction, elimination of internal pipeline development, and a focus on breast cancer for clinical development [5][6] - The company aims to generate important clinical data for EMILY from ongoing phase one dose expansion cohorts, with a focus on extending cash runway and prioritizing high B7-H4 expressing TNBC patients [6][17] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the prospects for EMILY, highlighting the potential for meaningful improvement over current standard care for post-Topo TNBC patients [11][17] - The company is preparing for upcoming clinical data presentations at ASCO, which are expected to provide further insights into the efficacy of EMILY [12][17] Other Important Information - The company has made protocol amendments to manage proteinuria in patients, which is a significant concern in ongoing trials [40][41] - The focus of expansion efforts will be exclusively on breast cancer, with no new expansion data expected for ovarian or endometrial cancer in 2025 due to resource prioritization [78] Q&A Session Summary Question: Can you expand on the high dose and safety updates? - Management clarified that the data shared at ASCO will focus on escalation and backfill, not expansion data [24] Question: How might ASCENT studies impact clinical development plans? - Management noted that the earlier use of Topo ADCs increases the post-Topo patient pool, which is a significant unmet need [33] Question: What types of patients were included in the recent response rates? - The two additional responses were from ACC1 patients, with further details to be shared at ASCO [42] Question: Are there additional dosing regimens being evaluated? - Management confirmed that the two doses currently in expansion are the only ones planned for now [47] Question: What are the expectations for the upcoming ASCO presentation? - Management emphasized that the ASCO presentation will focus on backfill and escalation data, with no expansion data included [49]