CellCentric Presents Positive Phase 2 Dose Optimization Data for Inobrodib in Multiple Myeloma at ASH Annual Meeting

- Observed response rates of 60-75% with inobrodib 20 mg and 30 mg cohorts result in clinical efficacy at least two-fold higher than previously published real-world data for pom-refractory, bispecific or anti-BCMA exposed patients -

Cambridge, United Kingdom and Boston, Massachusetts--(Newsfile Corp. - December 7, 2025) - CellCentric, a clinical-stage biotechnology company developing inobrodib as a first-in-class, oral p300/CBP inhibitor for the treatment of multiple myeloma (MM), today announced new data from dose optimization cohorts of its Phase 2 clinical trial of inobrodib in combination with pomalidomide (pom) and dexamethasone (dex; InoPd) in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM). Presented during a poster session at the American Society of Hematology (ASH) annual meeting, the data further validate a compelling efficacy and safety profile for the all-oral InoPd regimen, including in patients with high-risk disease and prior exposure to T-cell engagers (TCEs) and BCMA-targeted therapies.

"These Phase 2 dose optimization results reinforce our confidence that InoPd can transform outcomes for patients ineligible for or after bispecifics and/or other BCMA targeting agents. While bispecifics in particular have been transformative in the treatment of multiple myeloma, in later lines of therapy almost half of patients ultimately relapse and around one-third do not respond at all," said Will West, Chief Executive Officer of CellCentric. "InoPd offers a completely novel mechanism of action as an oral regimen that can be well tolerated. Following recent discussions with the FDA, we look forward to initiating pivotal registration studies next (Next Aktie) year."

Study participants were randomized to three dose levels of inobrodib (20mg, 30mg, 40mg, intermittent schedule), and standard dosing of 4mg pom and 20-40mg of dex depending on age. Among evaluable patients at this data cut (n=44, to a minimum of 60), the emerging objective response rate (ORR) was 69% for patients allocated to the 20mg cohort. Early analyses indicate more dose interruptions and de-escalations at higher doses, yielding emerging ORRs to date of 54% for 30mg and 33% for 40mg of inobrodib. Across all cohorts, responses continue to deepen and lengthen.

Specifically, among heavily pretreated (median five lines of prior therapy) pom-refractory patients who had previously failed on BCMA and/or TCE therapy, deep and durable ORRs were observed with 60% at 20mg and 75% at 30mg. This represents at least a two-fold increase against currently available MM therapies after BCMA/TCE agents, where real-world ORR rates are 25-30% in a similar patient population.

Data from the dose optimization study also reaffirmed the favorable tolerable safety profile of InoPd. The tolerability of the triplet, with inobrodib at 20mg, is in line with previously reported datasets of pom-dex alone, where patients were less heavily pre-treated. The most commonly reported treatment-emergent adverse events (TEAEs) of any grade in this new data were cytopenias and fatigue. Across the cohorts, the most common grade 3/4 TEAEs were thrombocytopenia (36%), neutropenia (34%) and anemia (20%).

"We are highly encouraged with the safety profile of InoPd in heavily pretreated patients, as we initially focus on addressing the growing unmet need of patients not tolerating or relapsing on bispecifics," said Tomasz Knurowski, M.D., Chief Medical Officer of CellCentric. "Coupled with the observed efficacy responses, many of which we expect will reach complete response and MRD-negative disease status as data matures, InoPd could have substantial impact as a first-in-class treatment for the multiple myeloma patient community."

About Inobrodib

Inobrodib is a potential new treatment for people with multiple myeloma (MM) and other cancers. It is an oral small molecule drug that targets the p300/CBP bromodomains to lower the expression of key cancer drivers, including MYC and IRF4. Inobrodib has been evaluated in over 450 patients to date and has a favorable safety and tolerability profile. Clinical activity has been seen in both hematologic malignancies and solid tumors. More than 70% of MM patients are treated in the community setting. Delivered as an oral capsule, inobrodib is easy for patients to take and designed be used at home without the need for intensive monitoring. The drug's differentiated profile may broaden use among patients who cannot tolerate or access other treatments, while its ease of administration could reduce healthcare system burden relative to more complex therapies.

Along with InoPd, inobrodib is being explored in combination with elranatamab and teclistamab. Proof of concept in a maintenance setting is also being explored. CellCentric maintains all development and commercial rights to inobrodib and is free to expand the program in combination with other agents.

About CellCentric 

CellCentric is a privately held biotechnology company advancing inobrodib, a first-in-class, orally bioavailable p300/CBP inhibitor. Inobrodib is being investigated in a Phase 2 clinical trial for patients with relapsed/refractory multiple myeloma, with additional indications under consideration. CellCentric is supported by a robust IP portfolio and external validation through clinical collaborations and strategic partnerships. Headquartered in the UK with expanding US operations, CellCentric is backed by a global syndicate of life science investors, including RA Capital Management, Forbion (and ForCal), Morningside, Pfizer Ventures, Avego, and the American Cancer Society's BrightEdge Fund.

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