Biopharmaceutical company Syros Pharmaceuticals has announced new clinical data from the Phase I/Ib clinical trial evaluating SY-5609 in patients with relapsed/refractory pancreatic ductal adenocarcinoma (PDAC), HR+ breast cancer and other solid tumours.
The data will be presented in two posters at the 2023 American Society for Clinical Oncology (ASCO) Annual Meeting, taking place June 2-6, in Chicago, Illinois.
“We are pleased to share data from our Phase I/Ib clinical trial of SY-5609, which further reinforce the potential of selective CDK7 inhibition as a potentially transformative approach for difficult-to-treat solid tumours,” said David Roth, Chief Medical Officer of Syros.
“SY-5609’s best in class selectivity and potency produce a predictable, well-managed tolerability profile, and we have optimised an intermittent dosing schedule that we believe enables broad combination potential. Data from both combination cohorts – evaluating SY-5609 in combination with chemotherapy in PDAC and SY-5609 with fulvestrant in HR+ breast cancer – demonstrate an acceptable tolerability profile, as well as promising clinical activity in heavily pre-treated populations that are unlikely to respond to standard of care.”
Single-agent and combination data
Syros will present updated data from the single agent dose escalation portion and the gemcitabine/nab-paclitaxel combination safety lead-in portion of the Phase I/Ib trial.
Encouraging clinical activity was observed at the maximum tolerated doses (MTD) with SY-5609 both as a single-agent (10mg) and in combination (4 or 5mg plus gemcitabine).
Among the three response evaluable patients with select solid tumours, data demonstrated a 100% disease control rate (DCR) with 10mg SY-5609 monotherapy, with the PDAC patient experiencing a 10% tumour reduction.
Of the nine PDAC patients treated with 4 or 5mg of SY-5609 in combination with gemcitabine, the data demonstrated a 44% DCR (four patients).
Syros will also present data from the fulvestrant combination cohort. Patients enrolled in this cohort presented with advanced disease: 11 had liver metastases and were heavily pre-treated, 14 had progressed on CDK4/6 therapy, while 12 had received prior fulvestrant.
The data show that the combination of SY-5609 and fulvestrant demonstrated an acceptable safety profile across a variety of dosing schedules. Five of the 12 patients achieved stable disease for a DCR of 42%; three of these five patients achieved target lesion regression.
