Efficient CAR T cell targeting of the CA125 extracellular repeat domain of MUC16.

BACKGROUND: Ovarian cancer (OC) is the leading cause of death from gynecologic malignancies in the Western world. Contributing factors include a high frequency of late-stage diagnosis, the development of chemoresistance, and the evasion of host immune responses. Currently, debulking surgery and platinum-based chemotherapy are the treatment cornerstones, although recurrence is common. As the clinical efficacy of immune checkpoint blockade is low, new immunotherapeutic strategies are needed. Chimeric antigen receptor (CAR) T cell therapy empowers patients' own T cells to fight and eradicate cancer, and has been tested against various targets in OC. A promising candidate is the MUC16 ectodomain. This ectodomain remains on the cell surface after cleavage of cancer antigen 125 (CA125), the domain distal from the membrane, which is currently used as a serum biomarker for OC. CA125 itself has not been tested as a possible CAR target. In this study, we examined the suitability of the CA125 as a target for CAR T cell therapy. METHODS: We tested a series of antibodies raised against the CA125 extracellular repeat domain of MUC16 and adapted them to the CAR format. Comparisons between these candidates, and against an existing CAR targeting the MUC16 ectodomain, identified K101 as having high potency and specificity. The K101CAR was subjected to further biochemical and functional tests, including examination of the effect of soluble CA125 on its activity. Finally, we used cell lines and advanced orthotopic patient-derived xenograft (PDX) models to validate, in vivo, the efficiency of our K101CAR construct. RESULTS: We observed a high efficacy of K101CAR T cells against cell lines and patient-derived tumors, in vitro and in vivo. We also demonstrated that K101CAR functionality was not impaired by the soluble antigen. Finally, in direct comparisons, K101CAR, which targets the CA125 extracellular repeat domains, was shown to have similar efficacy to the previously validated 4H11CAR, which targets the MUC16 ectodomain. CONCLUSIONS: Our in vitro and in vivo results, including PDX studies, demonstrate that the CA125 domain of MUC16 represents an excellent target for treating MUC16-positive malignancies.

European multidisciplinary tumor boards support cross-border networking and increase treatment options for patients with rare gynecological tumors.

OBJECTIVE: To evaluate outcomes of European cross-border multidisciplinary tumor boards in terms of participation, adherence to treatment recommendations, and access to novel treatment strategies. METHODS: The European reference network for rare gynecological tumors (EURACAN G2 domain) aims to improve the diagnosis, management, and treatment of patients with these cancers. Cross-border multidisciplinary tumor boards were initiated to facilitate intercollegiate clinical discussions across Europe and increase patients' access to specialist treatment recommendations and clinical trials. All G2 healthcare providers were invited to participate in monthly multidisciplinary meetings. Patient data were collected using a standardized form and case summaries were distributed before each meeting. After each tumor board, a meeting summary with treatment recommendations was sent to all participants and the project manager at the coordinating center. The multidisciplinary tumor board format and outcomes were regularly discussed at G2 domain meetings. Anonymized clinical data and treatment recommendations were registered in a prospective database. For this report, clinical data were collected between November 2017 and December 2020 and follow-up data retrieved until May 2021. RESULTS: During the 3-year period, 31 multidisciplinary tumor boards were held with participants from 10 countries and 20 centers. 91 individual patients were discussed between one and six times for a total of 109 case discussions. Follow-up data were retrieved from 64 patients and 80 case discussions. Adherence to treatment recommendations was 99%. Multidisciplinary tumor board recommendations resulted in 11 patients getting access to off-label treatment and one patient being enrolled in a clinical trial in another European country. 14/91 patients were recommended for surveillance only when additional treatment had been considered locally. CONCLUSION: Cross-border multidisciplinary tumor boards enable networking and clinical collaboration between healthcare professionals in different countries. Surveillance strategies, off-label drug use, and increased participation in clinical trials are possible benefits to patients with rare gynecological tumors.

Nordic gynecologists' opinion on quality assessment registers.

BACKGROUND: The Board of the Nordic Federation of Societies of Obstetrics and Gynecology established a Quality Group for Gynecological Surgery connected with benign diseases with one member from each of the Nordic countries. The aim was to suggest guidelines for the quality assessment of such surgery. METHODS: A questionnaire study was carried out in all Nordic gynecological departments concerning quality assessment and the elaboration of guidelines. RESULTS: Most of the departments (80.4%) want to participate in establishing and maintaining a quality register. The majority of responders strongly agree that registers detect areas of satisfactory as well as unsatisfactory quality, and are necessary for comparison of treatment results among departments. Several departments are hesitant about joining a register if it will incur financial costs (59.5%) and/or extra work (47.6%). Most departments (71.4-94.6%) consider that all major gynecological surgery should be monitored. The departments agree that pre-, per-, and post hospital patient events should be included in any register. These results are incorporated into common general guidelines for quality assessment of gynecological surgery in the Nordic countries. CONCLUSION: The gynecological departments in the Nordic countries agree on the necessity for and the main content of registers for quality assessment, but the interest drops when extra work is needed, and if the departments have to pay to participate, which emphasize the need for simple and low-cost registers. In accordance with the results of the Nordic questionnaire, common general quality guidelines for gynecological surgery are suggested.