IMPACT THERAP-B (07630) presented the latest clinical data for senaparib and the selective PARP1 inhibitors IMP1734 and IMP1707 in a poster presentation at the 2026 ESMO Congress.

IMPACT THERAP-B (07630) announced that the latest clinical data for its pipeline drugs senaparib (IMP4297), IMP1734 (also known as EIK1003), and IMP1707 (also known as EIK1004) were presented in poster presentations at the 2026 European Society for Medical Oncology (ESMO) Congress, held in Madrid, Spain, from October 23 to 27, 2026. Latest clinical data for senaparib: At a median follow-up of 48.5 months, the overall population continued to demonstrate a stable and statistically significant progression-free survival (PFS) benefit, with a median PFS of 38.7 months by blinded independent central review (BICR) versus 13.6 months for placebo (HR=0.47; 95% CI: 0.36, 0.62; p<0.0001). Importantly, the PFS benefit was consistent across both the BRCAm and BRCAwt patient subgroups, with median PFS in BRCAm patients of 49.8 months versus 15.6 months for senaparib and placebo (HR=0.41; 95% CI: 0.25, 0.70), and PFS in BRCAwt patients of 33.3 months versus 12.9 months (HR=0.49; 95% CI: 0.36, 0.68), further demonstrating that senaparib has a clear clinical benefit regardless of BRCA mutation status. Latest clinical data for IMP1734 Cohort 1B (in combination with abiraterone): IMP1734 combined with abiraterone showed tolerable safety and encouraging antitumor activity at all dose levels in patients with metastatic prostate cancer (mPC) after multiple lines of therapy. Among all Grade 3 TEAEs, anemia (15%) was the only hematologic adverse event observed with an incidence of 10%, indicating that this combination regimen has a favorable hematologic safety profile, consistent with the mechanism of highly selective PARP1 inhibition. Moreover, responses were observed in the HRR-mutant population regardless of BRCA mutation or non-BRCA (including ATM) mutation, indicating potential activity in a broader HRR-mutant population. Among 24 efficacy-evaluable participants, the ORR was 19.0% (4/21) in mCRPC and 33.3% (1/3) in mCSPC. Among 39 PSA-evaluable participants, the PSA response rate (PSA50) was 26.5% (9/34) in mCRPC and 60.0% (3/5) in mCSPC. These data support the feasibility of combining a selective PARP1 inhibitor with an androgen receptor pathway inhibitor. Latest clinical data for IMP1734 Cohorts 1A and 1C (monotherapy and combination with paclitaxel): Extended follow-up data from Cohort 1A reconfirmed that IMP1734 monotherapy has a favorable safety profile and durable responses in the heavily pretreated HRR-mutant population. The incidences of Grade 3 anemia and neutropenia were low, at 9.2% and 7.7%, respectively. The ORR in this heavily pretreated population was 14.3%, with one responder still on treatment for more than 21 months. In Cohort 1C, IMP1734 combined with weekly paclitaxel demonstrated a manageable safety profile in participants with advanced ovarian cancer and breast cancer who were not biomarker-selected. Its hematologic toxicity profile was similar to that previously observed in weekly paclitaxel monotherapy studies, with 49.2% and 18.0% of participants reporting Grade 3 neutropenia and anemia, respectively, indicating no visible additive hematologic toxicity from the combination. Encouraging antitumor activity was also observed in this population that had previously received extensive taxane and PARP inhibitor (PARPi) treatment. The ORR was 29.6% (8/27) in ovarian cancer and 23.1% (6/26) in breast cancer participants. Of the 14 participants who responded, 12 had previously received taxane therapy and 9 had previously received PARPi therapy. Notably, among ovarian cancer participants with prior PARPi treatment, the ORR was 38.1% (8/21), indicating that this combination can still achieve clinical benefit in participants who have failed prior PARPi therapy. These data also provide the first clinical confirmation that a selective PARP1 inhibitor can be safely combined with cytotoxic chemotherapy and maintain antitumor activity in populations previously treated with taxanes and PARPi, thereby addressing the needs of a population with highly unmet medical need. Latest clinical data for IMP1707: IMP1707 demonstrated a favorable safety profile consistent with its selective PARP1 mechanism of action. Hematologic toxicity was minimal, with the incidence of Grade 3 anemia and neutropenia both only 1.5%, and no Grade 3 thrombocytopenia events were observed. Early antitumor activity was observed across multiple tumor types, including ovarian cancer, prostate cancer, and breast cancer, with tumor shrinkage observed in heavily pretreated patients, including those with prior PARPi treatment. Among 4 efficacy-evaluable prostate cancer patients, 2 achieved partial response (PR) per RECIST 1.1. Notably, IMP1707 showed clinical benefit even at lower dose levels: one breast cancer patient achieved a confirmed complete response (CR) at the 20 mg dose level and has continued treatment for more than 10 months. Dr. Cai Suixiong, Chief Executive Officer of the Company, stated: "We are pleased that the latest clinical data for senaparib and the two novel selective PARP1 inhibitors IMP1734 and IMP1707 were presented at the 2026 ESMO Congress. These data further demonstrate the steady progress of our synthetic lethality pipeline. The updated progression-free survival (PFS) data from the Phase 3 FLAMES study of senaparib provide more mature evidence for senaparib as first-line maintenance therapy for the overall population of advanced ovarian cancer, with patients benefiting from senaparib treatment regardless of BRCA mutation status. Updated data from the IMP1734 monotherapy cohort and its combination cohorts with paclitaxel and abiraterone show that selective PARP1 inhibitors can be combined with chemotherapy and endocrine therapy with favorable efficacy and a manageable safety profile; while first-in-human data for the brain-penetrant IMP1707 in patients with HRR-mutant advanced solid tumors showed favorable tolerability and preliminary efficacy, providing initial clinical validation of the molecule's design. Looking ahead, we will continue to advance differentiated precision anticancer therapies, accelerate global clinical development of our products, and deepen our collaboration with Eikon Therapeutics, striving to bring tangible clinical benefits to cancer patients worldwide."