Safety and pharmacokinetics of a human monoclonal antibody to rabies virus: A randomized, dose-escalation phase 1 study in adults

9549 Background: Preclinical findings have shown a synergy between RT and anti-CTLA-4 monoclonal antibody in several tumor animal models for both local tumor control and distant effects. Preliminary clinical data suggest that it could be due to an abscopal effect of RT. The Mel-Ipi-Rx phase 1 study aimed to determine the maximum tolerated dose (MTD) and safety profile of RT combined with ipilimumab in pts with metastatic melanoma. Methods: A 3+3 dose escalation design was used with 9, 15, 18 and 24 Gy dose of RT (in 3 fractions) at week 4 combined with 10 mg/kg ipilimumab (every 3 weeks for 4 doses). Pts with evidence of clinical benefit at week 12 were eligible for maintenance ipilimumab at 10 mg/kg every 12 weeks starting at week 24 until severe toxicity or disease progression based on immune-related response criteria (irRC). Results: 19 pts with advanced melanoma received ipilimumab between August 2011 and July 2015. Nine pts received the 4 doses of ipilimumab and 2 pts received maintenance ipilimumab (1 and 2 cycles respectively). All pts received the combined RT at week 4 in 3 fractions. All pts presented at least one AE of any grade. The most common AEs were asthenia, diarrhea, desease-related pain and fever. Grade 3 AEs occurred in 8 pts. They included colitis (n = 3), hepatitis (n = 2), anemia (n = 2), asthenia (n = 1), thyroid disorders (n = 1) and nausea/vomiting (n = 1). Nine pts discontinued the study owing to treatment-related adverse events including colitis (n = 6), hepatitis (n = 2) and DRESS (Drug Rash with Eosinophilia and systemic syndrome) (n = 1). DLT occurred in 2/6 pts in the cohort receiving 15 Gy. No drug-related death occurred. According to irRC, 4 partial responses (ORR: 21%) and 4 stable diseases were observed at week 24. The MTD was 9 Gy dose. One pt out of 12 treated in the 9 Gy cohort presented a DLT (grade 3 colitis). The median progression-free survival [95% CI] was 7.2 months [2.4 – 16.8]. The median overall survival [95% CI] was 14.4 months [7.2 – 20.4]. Conclusions: When combined with ipilimumab at 10 mg/kg, in the present design, the MTD of RT was 9 Gy. This combination appears to be associated with antitumor activity. Clinical trial information: 2010-020317-93.

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Dose escalation phase 1 study of radiotherapy in combination with anti-cytotoxic-T-lymphocyte-associated antigen 4 monoclonal antibody ipilimumab in patients with metastatic melanoma

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-000627 ◽

2020 ◽

Vol 8 (2) ◽

pp. e000627 ◽

Cited By ~ 2

Author(s):

Celine Boutros ◽

Nathalie Chaput-Gras ◽

Emilie Lanoy ◽

Alicia Larive ◽

Christine Mateus ◽

...

Keyword(s):

Monoclonal Antibody ◽

Metastatic Melanoma ◽

T Lymphocyte ◽

Dose Escalation ◽

Clinical Benefit ◽

Cytotoxic T Lymphocyte ◽

Phase 1 ◽

Objective Response ◽

Severe Toxicity ◽

Phase 1 Study

BackgroundA synergy between radiotherapy and anti-cytotoxic-T-lymphocyte-associated antigen 4 (anti-CTLA-4) monoclonal antibody has been demonstrated preclinically. The Mel-Ipi-Rx phase 1 study aimed to determine the maximum tolerated dose (MTD) and safety profile of radiotherapy combined with ipilimumab in patients with metastatic melanoma.Patients and methodsA 3+3 dose escalation design was used with 9, 15, 18 and 24 Gy dose of radiotherapy at week 4 combined with 10 mg/kg ipilimumab every 3 weeks for four doses. Patients with evidence of clinical benefit at week 12 were eligible for maintenance with ipilimumab 10 mg/kg every 12 weeks starting at week 24 until severe toxicity or disease progression. The database lock occurred on April 30, 2019. Tumor growth rate of irradiated lesions and non-irradiated lesions were analyzed to assess the systemic immunologic antitumor response. Blood immune monitoring was performed before and during treatment to determine if radiotherapy could modify ipilimumab pharmacodynamics.Results19 patients received ipilimumab between August 2011 and July 2015. Nine patients received the four doses of ipilimumab. All patients received the combined radiotherapy. Grade 3 adverse events occurred in nine patients, the most common being colitis and hepatitis. No drug-related death occurred. Dose limiting toxicity occurred in two of six patients in the cohort receiving 15 Gy. The MTD was 9 Gy. Two patients had complete response, three had partial response response and seven had stable disease, giving an objective response rate of 31% and a clinical benefit rate of 75% at week 24. The median duration of follow-up was 5.8 years (Q1=4.5; Q3=6.8). The median overall survival (95% CI) was estimated at 0.9 years (0.5–2). The median progression-free survival (PFS) (95% CI) was 0.4 (0.2–1.4). Radiotherapy combined with ipilimumab was associated with increased CD4+ and CD8+ICOS+ T cells. Increased CD8+ was significantly associated with PFS.ConclusionWhen combined with ipilimumab at 10 mg/kg, the MTD of radiotherapy was 9 Gy. This combination of ipilimumab and radiotherapy appears to be associated with antitumor activity. Increased CD8+ was significantly associated with PFS. Thus, immune biomarkers may be useful for early response evaluation.Trial registration numberNCT01557114.

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