First-in-human phase 1 clinical trial of anti-core 1 O-glycans targeting monoclonal antibody NEO-201 in treatment-refractory solid tumors

BACKGROUND

NEO201 is a humanized IgG1 monoclonal antibody (mAb) generated against tumor-associated antigens from patients with colorectal cancer. NEO-201 binds to core 1 or extended core 1 O-glycans expressed by its target cells. Here, we present outcomes from a phase I trial of NEO-201 in patients with advanced solid tumors that have not responded to standard treatments.

METHODS

This was a single site, open label 3 + 3 dose escalation clinical trial. NEO-201 was administered intravenously every two weeks in a 28-day cycle at dose level (DL) 1 (1 mg/kg), DL 1.5 (1.5 mg/kg) and DL 2 (2 mg/kg) until dose limiting toxicity (DLT), disease progression, or patient withdrawal. Disease evaluations were conducted after every 2 cycles. The primary objective was to assess the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of NEO-201. The secondary objective was to assess the antitumor activity by RECIST v1.1. The exploratory objectives assessed pharmacokinetics and the effect of NEO-201 administration on immunologic parameters and their impact on clinical response.

RESULTS

Seventeen patients (11 colorectal, 4 pancreatic and 2 breast cancers) were enrolled; 2 patients withdrew after the first dose and were not evaluable for DLT. Twelve of the 15 patients evaluable for safety discontinued due to disease progression and 3 patients discontinued due to DLT (grade 4 febrile neutropenia [1 patient] and prolonged neutropenia [1 patient] at DL 2, and grade 3 prolonged (> 72 h) febrile neutropenia [1 patient] at DL 1.5). A total of 69 doses of NEO-201 were administered (range 1-15, median 4). Common (> 10%) grade 3/4 toxicities occurred as follows: neutropenia (26/69 doses, 17/17 patients), white blood cell decrease (16/69 doses, 12/17 patients), lymphocyte decrease (8/69 doses, 6/17 patients). Thirteen patients were evaluable for disease response; the best response was stable disease (SD) in 4 patients with colorectal cancer. Analysis of soluble factors in serum revealed that a high level of soluble MICA at baseline was correlated with a downregulation of NK cell activation markers and progressive disease. Unexpectedly, flow cytometry showed that NEO-201 also binds to circulating regulatory T cells and reduction of the quantities of these cells was observed especially in patients with SD.

CONCLUSIONS

NEO-201 was safe and well tolerated at the MTD of 1.5 mg/kg, with neutropenia being the most common adverse event. Furthermore, a reduction in the percentage of regulatory T cells following NEO-201 treatment supports our ongoing phase II clinical trial evaluating the efficiency of the combination of NEO-201 with the immune checkpoint inhibitor pembrolizumab in adults with treatment-resistant solid tumors.

TRIAL REGISTRATION

NCT03476681 . Registered 03/26/2018.

Intraperitoneal Monocytes plus IFNs as a Novel Cellular Immunotherapy for Ovarian Cancer: Mechanistic Characterization and Results from a Phase I Clinical Trial

PURPOSE

Ovarian cancer is the most lethal gynecologic cancer and intrinsically resistant to checkpoint immunotherapies. We sought to augment innate immunity, building on previous work with IFNs and monocytes.

PATIENTS AND METHODS

Preclinical experiments were designed to define the mechanisms of cancer cell death mediated by the combination of IFNs α and γ with monocytes. We translated these preclinical findings into a phase I trial of autologous IFN-activated monocytes administered intraperitoneally to platinum-resistant or -refractory ovarian cancer patients.

RESULTS

IFN-treated monocytes induced caspase 8-dependent apoptosis by the proapoptotic TRAIL and mediated by the death receptors 4 and 5 (DR4 and DR5, respectively) on cancer cells. Therapy was well tolerated with evidence of clinical activity, as 2 of 9 evaluable patients had a partial response by RECIST criteria, and 1 additional patient had a CA-125 response. Upregulation of monocyte-produced TRAIL and cytokines was confirmed in peripheral blood. Long-term responders had alterations in innate and adaptive immune compartments.

CONCLUSIONS

Given the mechanism of cancer cell death, and the acceptable tolerability of the clinical regimen, this platform presents a possibility for future combination therapies to augment anticancer immunity. See related commentary by Chow and Dorigo, p. 299.

Prenatal cfDNA Sequencing and Incidental Detection of Maternal Cancer

BACKGROUND

Cell-free DNA (cfDNA) sequence analysis to screen for fetal aneuploidy can incidentally detect maternal cancer. Additional data are needed to identify DNA-sequencing patterns and other biomarkers that can identify pregnant persons who are most likely to have cancer and to determine the best approach for follow-up.

METHODS

In this ongoing study we performed cancer screening in pregnant or postpartum persons who did not perceive signs or symptoms of cancer but received unusual clinical cfDNA-sequencing results or results that were nonreportable (i.e., the fetal aneuploidy status could not be assessed) from one of 12 different commercial laboratories in North America. We used a uniform cancer-screening protocol including rapid whole-body magnetic resonance imaging (MRI), laboratory tests, and standardized cfDNA sequencing for research purposes with the use of a genomewide platform. The primary outcome was the presence of cancer in participants after the initial cancer-screening evaluation. Secondary analyses included test performance.

RESULTS

Cancer was present in 52 of the 107 participants in the initial cohort (48.6%). The sensitivity and specificity of whole-body MRI in detecting occult cancer were 98.0% and 88.5%, respectively. Physical examination and laboratory tests were of limited use in identifying participants with cancer. Research sequencing showed that 49 participants had a combination of copy-number gains and losses across multiple (≥3) chromosomes; cancer was present in 47 of the participants (95.9%) with this sequencing pattern. Sequencing patterns of cfDNA in which there were only chromosomal gains (multiple trisomies) or only chromosomal losses (one or more monosomies) were found in participants with nonmalignant conditions, such as fibroids.

CONCLUSIONS

In this study, 48.6% of participants who received unusual or nonreportable clinical cfDNA-sequencing results had an occult cancer. Further study of DNA-sequencing patterns that are suggestive of occult cancer during prenatal screening is warranted. (Funded by the NIH Intramural Research Programs; ClinicalTrials.gov number, NCT04049604.).