C4 Therapeutics Announces First Patient Dosed in Phase 1b Trial of Cemsidomide in Combination with Elranatamab (ELREXFIO®) for Relapsed/Refractory Multiple Myeloma
Rhea-AI Summary
C4 Therapeutics (Nasdaq: CCCC) announced the first patient has been dosed in a Phase 1b trial of oral cemsidomide plus dexamethasone with FDA-approved elranatamab (ELREXFIO) for relapsed/refractory multiple myeloma.
The open-label, multicenter study will enroll up to 54 patients, test 50/75/100 µg cemsidomide doses, assess safety/tolerability as the primary endpoint, and aims to report Phase 1b data in mid-2027. Pfizer supplies elranatamab at no cost per the collaboration.
Positive
- First patient dosed in Phase 1b combining cemsidomide and elranatamab
- Trial will enroll up to 54 patients
- Dose exploration includes 50 µg, 75 µg, and 100 µg of cemsidomide
- Pfizer provides elranatamab at no cost under collaboration
- Phase 1b data anticipated in mid-2027
- Phase 2 MOMENTUM ongoing for fourth-line cemsidomide use
Negative
- Primary endpoint is safety/tolerability; no efficacy guarantee yet
- Maximum planned sample size is limited to 54 patients
News Market Reaction – CCCC
In the Mar 25 session, CCCC gained 7.60%, reflecting a notable positive market reaction. Our momentum scanner triggered 3 alerts that day, indicating moderate trading interest and price volatility.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Mar 09 | Inducement option grant | Neutral | -13.1% | Announced non-qualified stock option inducement grant under Nasdaq Rule 5635(c)(4). |
| Feb 26 | Earnings and pipeline | Positive | +0.4% | Reported 2025 results, strong cash of $297.1M and cemsidomide progress. |
| Feb 23 | Conference participation | Positive | +6.5% | Announced March 2026 healthcare conference appearances with webcast access. |
| Feb 23 | Clinical trial start | Positive | +6.5% | First patient dosed in Phase 2 MOMENTUM trial of cemsidomide plus dexamethasone. |
| Feb 09 | Inducement option grant | Neutral | +3.4% | Inducement grant of non-qualified stock options for a new employee. |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
Recent clinically and strategically focused updates on cemsidomide and corporate activities have generally seen aligned price reactions, with no clear pattern of the stock fading positive pipeline news.
Over recent months, C4 Therapeutics has highlighted steady progress for cemsidomide and broader corporate activity. In February 2026, the company dosed the first patient in the Phase 2 MOMENTUM trial and confirmed plans for this Phase 1b elranatamab combo. Earnings on Feb 26, 2026 underscored a cash position of $297.1M and funding projected to the end of 2028. Multiple inducement option and RSU grants and conference participation also featured, with market reactions mostly aligning with the generally constructive operational updates.
Key Terms
ikzf1/3 degrader medical
b-cell maturation antigen medical
cd3 medical
bispecific antibody medical
overall response rate medical
minimal-residual disease medical
international myeloma working group medical
AI-generated analysis. How Rhea-AI works. Not financial advice.
Novel Combination Regimen Positions Cemsidomide for Use in Earlier Lines of Therapy
WATERTOWN, Mass., March 25, 2026 (GLOBE NEWSWIRE) -- C4 Therapeutics, Inc. (C4T) (Nasdaq: CCCC), a clinical-stage biopharmaceutical company dedicated to advancing targeted protein degradation science, today announced that the first patient has been dosed with cemsidomide, an oral IKZF1/3 degrader, in a Phase 1b trial evaluating cemsidomide and dexamethasone in combination with elranatamab (ELREXFIO®), an FDA-approved B-cell maturation antigen CD3 targeted bispecific antibody, for the treatment of relapsed/refractory multiple myeloma (RRMM).
“Data from our Phase 1 trial support cemsidomide as a potential best-in-class, next-generation IKZF1/3 degrader and the initiation of this Phase 1b trial, along with our late-line Phase 2 MOMENTUM trial, enable an efficient path toward bringing cemsidomide to growing myeloma patient populations across multiple lines of therapy,” said Len Reyno, M.D., chief medical officer of C4 Therapeutics. “Bispecific T-cell engagers have quickly become a critical treatment pillar in multiple myeloma while IKZF1/3 degraders remain foundational therapies across multiple lines and combination regimens in multiple myeloma. In this combination with elranatamab, we see an opportunity to leverage cemsidomide’s potent direct anti-myeloma effect and its ability to enhance the immune environment which has the potential to deliver a deeper and more durable therapeutic response for patients, including those in earlier lines of therapy.”
The Phase 1b trial is an open-label, multicenter study to establish an optimal dose for cemsidomide in combination with elranatamab by evaluating the safety and tolerability as well as preliminary anti-myeloma activity of cemsidomide in combination with elranatamab in RRMM patients. The trial will enroll up to 54 patients to evaluate cemsidomide in combination with elranatamab, beginning at the 75 µg dose of cemsidomide with the opportunity to explore 50 µg and 100 µg doses of cemsidomide. The primary endpoint is to assess the safety and tolerability of cemsidomide in combination with elranatamab. Secondary endpoints will evaluate anti-myeloma activity per the International Myeloma Working Group (IMWG) response criteria, which will include the overall response rate, minimal-residual disease (MRD)-negative complete response rate, duration of response and other relevant measures. In October 2025, C4T and Pfizer entered into a clinical trial collaboration supply agreement under which Pfizer provides elranatamab at no cost while C4T sponsors and conducts the clinical trial. Phase 1b data from all cohorts evaluating cemsidomide in combination with elranatamab is anticipated in mid-2027.
The Phase 1b trial is part of a broader developmental strategy to support cemsidomide’s use across multiple lines of treatment. This strategy also includes the ongoing Phase 2 MOMENTUM Trial investigating the use of cemsidomide and dexamethasone in the fourth line of treatment or later. In addition to these two trials, C4T intends to evaluate cemsidomide in combination with other anti-myeloma agents, and remains on track to share these plans in mid-2026.
About Cemsidomide
Cemsidomide is an investigational, orally bioavailable molecular glue degrader (MonoDAC® degrader) of IKZF1/3, transcription factors foundational to multiple myeloma biology. Data from the Phase 1 trial, which has completed enrollment, show cemsidomide’s differentiated safety and tolerability profile and potentially class-leading anti-myeloma activity that support the potential for durable outcomes.
About Cemsidomide in Combination with Elranatamab (ELREXFIO®)
The Phase 1b trial is designed to evaluate the safety, tolerability and preliminary efficacy of cemsidomide and dexamethasone in combination with elranatamab, an FDA-approved B-cell maturation antigen CD3 targeted bispecific antibody. Data generated from the cemsidomide Phase 1 trial in relapsed/refractory multiple myeloma demonstrate robust T-cell activation and cytokine expression across multiple doses. By activating immune T-cells, cemsidomide, when combined with a BCMAxCD3 bispecific such as elranatamab, may amplify the anti-myeloma immune response and lead to deeper and more durable responses. The study will evaluate different cemsidomide dose levels (beginning with 75 µg, with the opportunity to simultaneously explore 50 µg and 100 µg) in patients who have received one to four prior lines of therapy, which must have consisted of at least one IKZF1/3 degrader. Exclusion criteria for patients include those who have received prior treatment with a BCMA-directed T-cell engager or BCMA-directed CAR-T therapy. More information is available at clinicaltrials.gov (NCT07280013).
About the MOMENTUM Trial
MOMENTUM (Multi-center trial Of cemsidoMidE iN relapsed/refracTory mUltiple Myeloma) is a Phase 2, open-label, single-arm, study to evaluate efficacy, safety, pharmacokinetics and pharmacodynamics of cemsidomide in combination with dexamethasone in patients with relapsed/refractory multiple myeloma. Data from the Phase 1 trial identified 100 µg as the recommended Phase 2 dose. The primary endpoint is overall response rate per International Myeloma Working Group response criteria, as assessed by an independent review committee. Approximately 100 patients who have received at least three prior anti-myeloma regimens that must have included an IKZF1/3 degrader, a proteasome inhibitor, an anti-CD38 antibody, and a T-cell engager or CAR-T therapy will be enrolled in the trial. More information is available at clinicaltrials.gov (NCT07284758).
About Multiple Myeloma
Multiple myeloma (MM) is a rare blood cancer affecting plasma cells. Approximately 36,000 people in the United States are diagnosed with MM each year. Approved IKZF1/3 degraders remain foundational therapies across lines of MM treatment. Despite advances, including immune-directed approaches, most patients ultimately relapse, underscoring a growing need for new therapeutics options that continue to leverage IKZF1/3 degradation to drive myeloma cell death and T-cell activation.
About C4 Therapeutics
C4 Therapeutics (C4T) (Nasdaq: CCCC) is a clinical-stage biopharmaceutical company dedicated to delivering on the promise of targeted protein degradation science to create a new generation of medicines that transforms patients’ lives. C4T is progressing targeted oncology programs through clinical studies and leveraging its TORPEDO® platform to efficiently design and optimize small-molecule medicines to address difficult-to-treat diseases. C4T’s degrader medicines are designed to harness the body’s natural protein recycling system to rapidly degrade disease-causing proteins, offering the potential to overcome drug resistance, drug undruggable targets and improve patient outcomes. For more information, please visit www.c4therapeutics.com.
Forward Looking Statements
This press release contains “forward-looking statements” of C4 Therapeutics, Inc. within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements may include, but may not be limited to, express or implied statements regarding our ability to develop potential therapies for patients; the design and potential efficacy of our therapeutic approaches; the predictive capability of our TORPEDO® platform in the development of novel, selective, orally bioavailable BiDAC™ and MonoDAC® degraders; the potential timing, design and advancement of our preclinical studies and clinical trials, including the potential timing for and receipt of regulatory authorization related to clinical trials and other clinical development activities including clinical trial commencement and patient enrollment; our ability and the potential to successfully manufacture and supply our product candidates for clinical trials; our ability to replicate results achieved in our preclinical studies or clinical trials in any future studies or trials; our ability to replicate interim or early-stage results from our clinical trials in the results obtained when those clinical trials are completed or when those therapies complete later-stage clinical trials; regulatory developments in the United States and foreign countries; the anticipated timing and content of presentations of data from our clinical trials; and our ability to fund our future operations. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: uncertainties related to the initiation, timing, advancement and conduct of preclinical and clinical studies and other development requirements for our product candidates; the risk that any one or more of our product candidates will cost more to develop or may not be successfully developed and commercialized; and the risk that sufficient capital to fund our future operations will be available to us on acceptable terms or at the times required. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause our actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in C4 Therapeutics’ most recent Annual Report on Form 10-K and/or Quarterly Report on Form 10-Q, as filed with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and C4 Therapeutics undertakes no duty to update this information unless required by law.
Contacts:
Investors:
Courtney Solberg
Associate Director, Investor Relations
CSolberg@c4therapeutics.com
Media:
Loraine Spreen
Senior Director, Corporate Communications & Patient Advocacy
LSpreen@c4therapeutics.com
