Compass Therapeutics (CMPX) Jefferies London Healthcare Conference 2024 summary

Pipeline overview and clinical progress

• Three clinical-stage programs: DLL4 VEGF-A bispecific (lead), CD137 agonist, and PD-1/PD-L1 bispecific, with additional preclinical VEGF IO bispecifics nearing candidate nomination.

• Lead DLL4 VEGF-A bispecific (009) showed a 37.5% response rate in phase II BTC, with 63.6% in second-line patients, far exceeding historical controls.

• Randomized phase II/III BTC study is fully enrolled, comparing 009 plus paclitaxel to paclitaxel alone, with top-line response rate data expected by end of Q1 next year.

• Study is powered for a 23% absolute difference in response rate; primary endpoint is independently reviewed response rate.

• Additional studies include a frontline BTC trial with MD Anderson and a planned phase II in DLL4-positive CRC, with FDA guidance expected in early 2025.

Study design, regulatory strategy, and timelines

• BTC study randomizes second-line patients 2:1:1 to 009, 009+paclitaxel, or paclitaxel alone; patient population mirrors prior phase II except limited to second-line.

• FDA has not set a minimum response rate threshold, but emphasized the importance of the magnitude of difference between arms.

• Response rate readout is time-triggered (28 weeks post last enrollment), with PFS and OS analyses expected in the second half of next year.

• Accelerated approval may be possible if a 23% or greater response rate delta is achieved; lower deltas may require PFS/OS support.

• Crossover is allowed post-progression, with OS adjusted using the rank-preserving structural failure time method, as aligned with FDA.

Unmet need and market positioning

• BTC lacks a consensus second-line standard of care; only 15% of patients are eligible for targeted therapies, leaving 85% reliant on chemotherapy.

• 009 plus paclitaxel is positioned to become the consensus second-line standard for BTC.

• Prior studies in BTC show minimal response rates for current regimens, highlighting the significance of the observed efficacy.

• Enrollment for the BTC study was rapid once academic centers opened, reflecting the prevalence and concentration of patients at major centers.