Scholar Rock Holding Corporation announced that initiation of SRK-181 Phase 1 Dose Escalation and Dose Expansion Clinical Trial in Patients with Solid Tumors is Planned for the First Quarter of 2020. TGFß signaling has been implicated in driving immune exclusion, a key culprit of primary resistance to checkpoint inhibitor therapies by multiple academic and industrial groups. Scholar Rock is developing SRK-181 as a potential therapy in cancer immunotherapy to broaden responses to anti-PD-(L)1 therapies. In an aim to reduce toxicities associated with non-selective TGFß inhibition that have historically limited the ability to dose at clinically meaningful levels, SRK-181 has been designed to selectively block the TGFß1 isoform. An IND application for SRK-181 has been submitted to the FDA and Scholar Rock plans to initiate a Phase 1 proof-of-concept trial in the first quarter of 2020 in patients with locally advanced or metastatic solid tumors. The two-part trial will consist of a dose escalation portion for SRK-181 as both a single-agent and in combination with an approved anti-PD-(L)1 antibody, followed by a dose expansion portion evaluating SRK-181 in combination with an approved anti-PD-(L)1 antibody in multiple tumor-specific cohorts, such as urothelial carcinoma, melanoma, non-small cell lung cancer, and other solid tumors. Key objectives of the study include evaluating the safety and pharmacokinetics of SRK-181 and the efficacy of SRK-181 in combination with anti-PD-(L)1 therapy in the treatment of solid tumors exhibiting primary resistance to anti-PD-(L)1 therapy. Initial clinical data from the Phase 1 trial are expected in the second half of 2020 with clinical response and safety data anticipated in 2021.