Radiotherapy combined with nivolumab or temozolomide for newly diagnosed glioblastoma with unmethylated MGMT promoter: An international randomized phase III trial.

BACKGROUND: Addition of temozolomide (TMZ) to radiotherapy (RT) improves overall survival (OS) in patients with glioblastoma (GBM), but previous studies suggest that patients with tumors harboring an unmethylated MGMT promoter derive minimal benefit. The aim of this open-label, phase III CheckMate 498 study was to evaluate the efficacy of nivolumab (NIVO) + RT compared with TMZ + RT in newly diagnosed GBM with unmethylated MGMT promoter. METHODS: Patients were randomized 1:1 to standard RT (60 Gy) + NIVO (240 mg every 2 weeks for eight cycles, then 480 mg every 4 weeks) or RT + TMZ (75 mg/m2 daily during RT and 150-200 mg/m2/day 5/28 days during maintenance). The primary endpoint was OS. RESULTS: A total of 560 patients were randomized, 280 to each arm. Median OS (mOS) was 13.4 months (95% CI, 12.6 to 14.3) with NIVO + RT and 14.9 months (95% CI, 13.3 to 16.1) with TMZ + RT (hazard ratio [HR], 1.31; 95% CI, 1.09 to 1.58; P = .0037). Median progression-free survival was 6.0 months (95% CI, 5.7 to 6.2) with NIVO + RT and 6.2 months (95% CI, 5.9 to 6.7) with TMZ + RT (HR, 1.38; 95% CI, 1.15 to 1.65). Response rates were 7.8% (9/116) with NIVO + RT and 7.2% (8/111) with TMZ + RT; grade 3/4 treatment-related adverse event (TRAE) rates were 21.9% and 25.1%, and any-grade serious TRAE rates were 17.3% and 7.6%, respectively. CONCLUSIONS: The study did not meet the primary endpoint of improved OS; TMZ + RT demonstrated a longer mOS than NIVO + RT. No new safety signals were detected with NIVO in this study. The difference between the study treatment arms is consistent with the use of TMZ + RT as the standard of care for GBM.ClinicalTrials.gov NCT02617589.

Nivolumab plus radiotherapy with or without temozolomide in newly diagnosed glioblastoma: Results from exploratory phase I cohorts of CheckMate 143.

Background: The phase 1 cohorts (1c+1d) of CheckMate 143 (NCT02017717) evaluated the safety/tolerability and efficacy of nivolumab plus radiotherapy (RT) ± temozolomide (TMZ) in newly diagnosed glioblastoma. Methods: In total, 136 patients were enrolled. In part A (safety lead-in), 31 patients (n = 15, methylated/unknown MGMT promoter; n = 16, unmethylated MGMT promoter) received nivolumab and RT+TMZ (NIVO+RT+TMZ) and 30 patients with unmethylated MGMT promoter received NIVO+RT. In part B (expansion), patients with unmethylated MGMT promoter were randomized to NIVO+RT+TMZ (n = 29) or NIVO+RT (n = 30). Primary endpoint was safety/tolerability; secondary endpoint was overall survival (OS). Results: NIVO+RT±TMZ was tolerable; grade 3/4 treatment-related adverse events occurred in 51.6% (NIVO+RT+TMZ) and 30.0% (NIVO+RT) of patients in part A and 46.4% (NIVO+RT+TMZ) and 28.6% (NIVO+RT) in part B. No new safety signals were detected. In part A, median OS (mOS) with NIVO+RT+TMZ was 33.38 months (95% CI, 16.2 to not estimable) in patients with methylated MGMT promoter. In patients with unmethylated MGMT promoter, mOS was 16.49 months (12.94-22.08) with NIVO+RT+TMZ and 14.41 months (12.55-17.31) with NIVO+RT. In part B, mOS was 14.75 months (10.01-18.6) with NIVO+RT+TMZ and 13.96 months (10.81-18.14) with NIVO+RT in patients with unmethylated MGMT promoter. Conclusions: CheckMate 143 was the first trial evaluating immune checkpoint inhibition with first-line treatment of glioblastoma. Results showed that NIVO can be safely combined with RT±TMZ, with no new safety signals. Toxicities, including lymphopenia, were more frequent with NIVO+RT+TMZ. OS was similar with or without TMZ in patients with unmethylated MGMT promoter, and differences by MGMT methylation status were observed.

Successful re-challenge with panitumumab in patients who developed hypersensitivity reactions to cetuximab: report of three cases and review of literature.

INTRODUCTION: Monoclonal antibodies (MAbs) targeting epidermal growth factor receptor (EGFR) are effective in treatment of metastatic colorectal cancer (mCRC). Cetuximab, a chimeric MAb targets EGFR. Even with premedication, cetuximab can cause a hypersensitivity reaction (HSR). In case of severe HSR, further therapy with cetuximab is contraindicated, thus preventing these patients from receiving potentially beneficial anti-EGFR therapy. Panitumumab is a fully human MAb also targets EGFR. To date, no human antihuman Ab have been detected, and unlike CET, HSR are infrequent, and no premedication is required. Safety of panitumumab in patients with a previous severe HSR with cetuximab is not fully known. We present three patients with GI cancers who tolerated panitumumab without HSR after experiencing severe HSR to cetuximab. PATIENTS AND METHODS: Three patients were challenged with standard dose of panitumumab (6 mg/kg) after experiencing grade 3 HSR to standard dose of cetuximab under strict observation and no premedication. First patient, a 58-year-old male with mCRC developed grade 3 HSR during 8th dose of cetuximab. Second patient was a 58-year-old female with mCRC developed grade 3 HSR during 12th dose of cetuximab. Third patient was a 61-year-old male with pancreatic cancer who experienced grade 3 HSR during loading dose of cetuximab. Charts were reviewed to find history of prior allergy, including H1 blocker use, drug allergy, bee sting allergy, eczema, allergic reactive airways disease, or food allergy. RESULTS: All patients were Caucasians with an average age of 59 year with no history of prior allergy. No patient received any premedication. First patient received panitumumab for 2 months, second patient was treated for 6 months, and third patient who was rechallenged 1 week after HSR to cetuximab had a partial response following 6 months of therapy. CONCLUSIONS: HSR are serious complications associated with MAbs. Thanks to hybridoma technology that newer generations of MAbs contain less or no mouse-specific protein sequences, hence reducing the risk of HSR. Identification of individuals likely to develop severe and sometimes life-threatening HSR is challenging. Our report of three patients successfully treated with panitumumab after they had severe HSR to cetuximab warrant further investigation.