C4 Therapeutics: SUCCESSOR-2 a Success but Data Leaves Room for Cemsidomide Given Clinical Profile to Date

Research evidence excerpt

C4 Therapeutics: SUCCESSOR-2 a Success but Data Leaves Room for Cemsidomide Given Clinical Profile to Date

Equity Research

U.S. Small & Mid Cap Biotechnology

29 May 2026

C4 Therapeutics

SUCCESSOR-2 a Success but Data

Leaves Room for Cemsidomide First Look

CCCC OVERWEIGHTGiven Clinical Profile to Date

U.S. Small & Mid Cap POSITIVE

CCCC's clinical profile suggests opportunity to differentiate Biotechnology Price Target USD 7.00

from mezigdomide in pivotal studies. Price (28-May-26) USD 3.66

Potential Upside/Downside +91.3%

Source: Bloomberg, Barclays Research

THE 2026 EXTEL SURVEY IS NOW OPEN Etzer Darout, PhD, MBA

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Support our industry-leading analysts with 5-Star etzer.darout@barclays.com BCI, US

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BCI, US

Vote Now View Analysts Jordan Becker, PhD

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Gustave Diep, MD

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The ASCO late breaking abstract for BMY's (covered by Emily Field) Phase 3 SUCCESSOR-2 trial gustave.diep@barclays.com

evaluating mezigdomide plus carfilzomib (proteasome inhibitor, PI) plus dexamethasone versus BCI, US

carfilzomib and dexamethasone was published this morning. The trial enrolled relapsed/

refractory multiple myeloma (MM) patients with a median of 2 prior lines of therapy. ORR for the

mezigdomide regimen was 80.2% versus 53.4% with complete response or better of 26.7%

versus 8.9%. PFS was also improved at 18.0 months versus 8.3 months, a 52% risk reduction (HR

0.48). The safety profile was similar to mezigdomide's previously reported profile, with Grade 3+

neutropenia occurring in 61.1% of patients.

In our view, the data leaves room for cemsidomide to improve with its own PI combination.