Safety Profile and Clinical Response To MEDI-551, a Humanized Monoclonal Anti-CD19, In a Phase 1/2 Study In Adults With Relapsed Or Refractory Advanced B-Cell Malignancies
Bibliographic record
Abstract
Abstract Background MEDI-551 is an affinity-optimized and afucosylated humanized IgG kappa monoclonal antibody directed against CD19 and induces malignant clone destruction by antibody-dependent cellular cytotoxicity. This study evaluates the safety profile and clinical activity of MEDI-551 in patients with relapsed/refractory B-cell malignancies. These include chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and multiple myeloma (MM). Objectives Determine the safety profile and maximum tolerated dose (MTD) of MEDI-551 in patients with relapsed/refractory B-cell malignancies. Secondary objectives include clinical activity of MEDI-551. Methods In this phase 1/2 open-label multicenter, global dose-escalation and expansion study, patients with relapsed or refractory CLL, DLBCL, FL, or MM received MEDI-551 (at 0.5, 1, 2, 4, 8, or 12 mg/kg) by intravenous infusion administered over 28-day cycles using standard 3+3 dose escalation. Dose escalation continued to the maximum dose ≤12 mg/kg or until MTD was reached. Therapy continued for 2 cycles beyond complete response (CR), or until unacceptable toxicity or disease progression. Dose-limiting toxicity was defined as a MEDI-551-related adverse event (AE) that prevented completion of a full first cycle of MEDI-551, or as a ≥grade 3 toxicity (excluding hematologic toxicity) that could not be ascribed to another cause. Results Of 91 patients who received ≥1 dose of MEDI-551, 25 patients (CLL [3], DLBCL [6], FL [12], MM [4]) were enrolled in the phase 1 escalation portion (Jun 2010–Aug 2011). No MTD was achieved. The phase 2 expansion phase included 66 patients (CLL [23], DLBCL [20], FL [22], MM [1]) as of 14Jul2013. Three patients were re-treated with MEDI-551 upon relapse. Median age of patients treated was 66 years; median lines of prior therapy was 6. The median number of treatment cycles was 5 with a maximum of 28 cycles. There were 14 deaths due to AEs (none were drug-related) and 15 subjects discontinued treatment. One subject each discontinued due to drug-related neutropenia and infusion reaction. Most AEs were grade 1/2 with dose-independent frequency and severity (Table). Of 91 patients, 5 (5.5%) patients had grade 4 TEAEs (2 with drug-related neutropenia) and 9 (9.9%) had grade 5 events, none were drug related. Of 19 patients with 38 serious AEs (SAE), 2 patients had 3 events that were considered drug-related; pneumonia and sepsis in 1 patient and infusion related reaction in the other. Of 83 patients in the efficacy evaluable population (includes all patients who received any treatment of MEDI-551 and completed at least 1 post-baseline disease assessment), 9 had CR, 12 had partial responses (PR) and 42 had stable disease (SD; Figure 1). ORR to single-agent MEDI-551 was 24%, 24%, or 31% respectively in heavily pre-treated patients with CLL, DLBCL, or FL. Median progression-free survival was ≈9 months (Figure 2). Conclusions MEDI-551 has an acceptable safety profile warranting further study. Anti-tumor activity was achieved in a heavily pre-treated population of DLBCL, CLL, and FL patients respectively in this single-agent study. Phase 2 studies of MEDI-551 in combination with chemotherapy in DLBCL and CLL are ongoing. Funding Source This study was sponsored by MedImmune. Disclosures: Forero-Torres: MedImmune: Research Funding. Hamadani:MedImmune: Research Funding. Fanale:MedImmune: Research Funding. Bello:MedImmune: Research Funding. Kipps:MedImmune: Research Funding. Offner:MedImmune: Research Funding. Verhoef:MedImmune: Research Funding. Federico:MedImmune: Research Funding. Gregory:MedImmune: Research Funding. Sonet:MedImmune: Research Funding. Assouline:MedImmune: Research Funding. Pérez de Oteyza:MedImmune: Research Funding. Tomas:MedImmune: Research Funding. Cuneo:MedImmune: Research Funding. Elgeioushi:MedImmune: Employment, Stock/stock options from AstraZeneca Other. Goswami:MedImmune: Employment, Stock/stock options from AstraZeneca Other. Ibrahim:MedImmune: Employment, Stock/stock options from AstraZeneca Other. Herbst:MedImmune: Employment, Stock/stock options from AstraZeneca Other. Cheson:MedImmune: Research Funding.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".