Background:
* LMB-100, and a closely related immunotoxin, SS1P, also targeting mesothelin, have been studied in previous Phase 1 clinical studies for mesothelioma and pancreatic cancer.
* LMB-100 has demonstrated anti-tumor efficacy against several mesothelin expressing tumor models including mesothelioma patient-derived xenografts (PDX) models
* Programmed cell death protein 1 (PD-1) (encoded by the gene Pdcd1) is an Ig superfamily member related to cluster of differentiation 28 (CD28) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) that has been shown to negatively regulate antigen receptor signaling upon engagement of its ligands
* The PD-1 receptor-ligand interaction is a major pathway hijacked by tumors to suppress immune control. The normal function of PD-1, expressed on the cell surface of activated T-cells under healthy conditions, is to down-modulate unwanted or excessive immune responses, including autoimmune reactions.
* In immune-competent mice bearing human mesothelin expressing tumors local administration of LMB-100 with CTLA-4 blockade eradicates murine tumors by promoting anti-cancer immunity.
* LMB-100 treatment increase cluster of differentiation 8 (CD8)+ T cell infiltration in murine lung adenocarcinoma tumors that express human mesothelin.
* Combination treatment with LMB-100 plus anti-PD1 results in greater anti-tumor efficacy in murine lung cancer model
* Pembrolizumab is an anti PD-1 antibody that has demonstrated responses of long duration in clinical trials and has generally been well-tolerated
* It is hypothesized that the anti-mesothelin immunotoxin LMB-100 followed by pembrolizumab will result in greater anti-tumor efficacy in patients with mesothelioma.
Objectives:
\- To determine the objective response rate of sequential therapy with LMB-100 followed by pembrolizumab in subjects with pleural and peritoneal mesothelioma.
Eligibility:
* Histologically confirmed epithelial or biphasic pleural or peritoneal mesothelioma (with \<50% sarcomatoid component) not amenable to potentially curative surgical resection.
* Subjects must have at least one prior chemotherapy regimen that includes pemetrexed and cisplatin or carboplatin.
* Age greater than or equal to 18 years.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
* Adequate organ and bone marrow function
* Prior PD1/Programmed death-ligand 1 (PD-L1) inhibitor treatment is prohibited
* Chemotherapy within 4 weeks or radiotherapy within 2 weeks prior to start of study therapy is prohibited.
* Subjects with active central nervous system (CNS) metastasis are excluded
* Subjects with active autoimmune disease for which they had received systemic treatment during the previous 2 years receiving systemic glucocorticoids (excluding daily glucocorticoid-replacement therapy for conditions such as adrenal or pituitary insufficiency) are excluded
* Subjects with active interstitial lung disease, or a history of pneumonitis for which they had received glucocorticoids are excluded
Design:
* This is an open-label, single center phase II study of LMB-100 followed by pembrolizumab in subjects with advanced pleural or peritoneal mesothelioma who have progressed on standard therapies.
* Subjects will receive LMB-100 at the single agent maximum tolerated dose (MTD) on days 1, 3 and 5 of a 21-day cycle for 2 cycles and pembrolizumab 200 mg on day 1 of each subsequent 21-day cycle until disease progression (on or after pembrolizumab) or intolerable toxicity for a maximum of 2 years (unless second course initiated).
* Tumor biopsies will be performed at baseline, at the end of cycle 2 and at the end of cycle 4 to evaluate changes in the tumor immune microenvironment following treatment with LMB-100 and pembrolizumab.
* Up to 35 evaluable subjects will be enrolled