Abstract 1069: Autologous γδ T cell therapy for treatment-refractory non-small-cell lung cancer: An open-label, single-arm, multicenter, phase II study
Authors: Kakimi Kazuhiro , Matsushita Hirokazu , Izumi Takamichi , Masuzawa Keita , Karasaki Takahiro , Ikemura Shinnosuke , Kitano Kentaro , Kawata Ichiro , Manabe Tadashi , Takehara Tomohiro , Ebisudani Toshiaki , Nagayama Kazuiro , Yasuda Hiroyuki , Sato Masaaki , Soejima Kenzo , Nakajima Jun 
Published: September 2020

Background: Only a fraction of non-small cell lung cancer (NSCLC) patients possess targetable driver mutations, and the response rates of immune checkpoint blockades are still unsatisfactory. Therefore, the development of more effective therapies is needed for treatment-refractory NSCLC. We conducted a phase I clinical study of autologous γδ T cell therapy for NSCLC patients and reported safety and feasibility. Here, we report the result of phase II clinical trial of adoptive γδ T cell transfer therapy for treatment-refractory NSCLC patients.

Methods: Patients with NSCLC who had undergone at least two regimens of standard chemotherapy for unresectable disease or who had undergone at least one treatment including chemotherapy or radiation for recurrent disease after surgery were enrolled in this open-label, single-arm, multicenter, phase II study. After preliminary testing of γδ T cell proliferative capacity, mononuclear cells of the patient collected by peripheral blood leukapheresis were cultured with zoledronic acid and IL-2. Expanded autologous γδ T cells (&gt;1 × 109) were transferred intravenously every two weeks for a total of six injections. If the patient perceived some clinical benefit, the patient could continue further treatments until the disease became progressive. The primary endpoint of this study was progression-free survival (PFS), and the secondary endpoints included overall survival (OS), best objective response rate (ORR), disease control rate (DCR), and safety. The clinical efficacy of the treatment was determined if the median PFS is significantly longer than 3 months.

Results: Autologous γδ T cell therapy was given for 25 patients, and 16 patients completed the 6 courses of the treatment. Among the 25 patients, 20 had adenocarcinoma, 4 squamous cell carcinoma and 1 large cell carcinoma. The median PFS was 95.0 days (95% CI 73.0-132.0 days). The median OS was 418.0 days (179.0-479.0 days). The best overall responses were 1 partial response (PR), 16 stable disease (SD) including 4 patients whose time to progression was longer than 180 days, and 8 progressive disease (PD). ORR and DCR were 4.0% (0.1-20.4%) and 68.0% (46.5-85.1%), respectively. Severe adverse events (SAE) were developed in 9 patients during the study, including pleural effusion, anorexia, cough, dyspnea, respiratory failure, pneumonitis, ascites, tumor pain, and intracranial hemorrhage. Most of them were associated with disease progression; however, a case of pneumonitis was related to γδ T cell therapy.

Conclusion: Although the trial did not meet its primary efficacy endpoint, the results of this study indicate that autologous γδ T cell therapy was well tolerated and may have an acceptable disease control rate. Considering the unique mechanism of action towards tumor cells, γδ T cell therapy may be a candidate counterpart of combination therapy for treatment-refractory NSCLC.

Citation Format: Kazuhiro Kakimi, Hirokazu Matsushita, Takamichi Izumi, Keita Masuzawa, Takahiro Karasaki, Shinnosuke Ikemura, Kentaro Kitano, Ichiro Kawata, Tadashi Manabe, Tomohiro Takehara, Toshiaki Ebisudani, Kazuiro Nagayama, Hiroyuki Yasuda, Masaaki Sato, Kenzo Soejima, Jun Nakajima. Autologous γδ T cell therapy for treatment-refractory non-small-cell lung cancer: An open-label, single-arm, multicenter, phase II study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1069.