Junko Baba

Clinical responses to EGFR-tyrosine kinase inhibitor retreatment in non-small cell lung cancer patients who benefited from prior effective gefitinib therapy: a retrospective analysis

BackgroundGefitinib was the first epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) approved for the treatment of advanced non-small cell lung cancer (NSCLC). Few treatment options are available for NSCLC patients who have responded to gefitinib treatment and demonstrated tumor progression. The present study was conducted to evaluate the efficacy and toxicity of the 2nd EGFR-TKI administration.MethodsWe retrospectively analyzed 11 patients who had obtained a partial response (PR) or stable disease (SD) with gefitinib treatment and were re-treated with EGFR-TKI after failure of the initial gefitinib treatment.ResultsThree patients (27%) were treated with gefitinib as the 2nd EGFR-TKI, and 8 patients (73%) received erlotinib. Only one patient (9%) showed PR, 7 (64%) achieved SD, and 3 (27%) had progressive disease. The disease control rate was 73% (95% CI, 43% - 91%) and the median progression-free survival was 3.4 months (95% CI, 2 - 5.2). The median overall survival from the beginning of the 2nd EGFR-TKI and from diagnosis were 7.3 months (95% CI, 2.7 - 13) and 36.7 months (95% CI, 23.6 - 43.9), respectively. No statistical differences in PFS or OS were observed between gefitinib and erlotinib as the 2nd EGFR-TKI (PFS, P = 0.23 and OS, P = 0.052). The toxicities associated with the 2nd EGFR-TKI were generally acceptable and comparable to those observed for the initial gefitinib therapy.ConclusionsOur results indicate that a 2nd EGFR-TKI treatment can be an effective treatment option for gefitinib responders.

Vaccination with CD133+ melanoma induces specific Th17 and Th1 cell–mediated antitumor reactivity against parental tumor

Accumulating evidence suggests that cancer cells possess a small subpopulation that survives during potentially lethal stresses, including chemotherapy, radiation treatment, and molecular-targeting therapy. CD133 is a putative marker that distinguishes a minor subpopulation from normal differentiated tumor cells in many cancers. Although it is necessary to eradicate all cancer cells to obtain a cure, effective treatment to eliminate the CD133+ treatment–tolerant cells has not been elucidated. In this study, we demonstrated that a CD133+ subpopulation in murine melanoma is immunogenic and that effector T cells specific for the CD133+ melanoma cells mediated potent antitumor reactivity, curing the mice of the parental melanoma. CD133+ melanoma antigens preferentially induced type 17 T helper (Th17) cells and Th1 cells but not Th2 cells. CD133+ melanoma cell–specific CD4+ T-cell treatment eradicated not only CD133+ tumor cells but also CD133− tumor cells while inducing long-lasting accumulation of lymphocytes and dendritic cells with upregulated MHC class II in tumor tissues. Further, the treatment prevented regulatory T-cell induction. These results indicate that T-cell immunotherapy is a promising treatment option to eradicate CD133+ drug-tolerant cells to obtain a cure for cancer.

Critical Roles of Chemoresistant Effector and Regulatory T Cells in Antitumor Immunity after Lymphodepleting Chemotherapy.

Antitumor immunity is augmented by cytotoxic lymphodepletion therapies. Adoptively transferred naive and effector T cells proliferate extensively and show enhanced antitumor effects in lymphopenic recipients. Although the impact of lymphodepletion on transferred donor T cells has been well evaluated, its influence on recipient T cells is largely unknown. The current study demonstrates that both regulatory T cells (Tregs) and effector CD8+ T cells from lymphopenic recipients play critical roles in the development of antitumor immunity after lymphodepletion. Cyclophosphamide (CPA) treatment depleted lymphocytes more efficiently than other cytotoxic agents; however, the percentage of CD4+CD25+ Foxp3+ Tregs was significantly increased in CPA-treated lymphopenic mice. Depletion of these chemoresistant Tregs following CPA treatment and transfer of naive CD4+ T cells augmented the antitumor immunity and significantly suppressed tumor progression. Further analyses revealed that recipient CD8+ T cells were responsible for this augmentation. Using Rag2−/− mice or depletion of recipient CD8+ T cells after CPA treatment abrogated the augmentation of antitumor effects in CPA-treated reconstituted mice. The transfer of donor CD4+ T cells enhanced the proliferation of CD8+ T cells and the priming of tumor-specific CD8+ T cells originating from the lymphopenic recipients. These results highlight the importance of the recipient cells surviving cytotoxic regimens in cancer immunotherapies.

Recurrent Interstitial Lung Disease Induced By Various Therapies forNon-Small Cell Lung Cancer

Erlotinib is a human epidermal growth factor receptor type 1 tyrosine kinase inhibitor which is used for non-small cell lung cancer treatment. Interstitial lung disease has been reported as an adverse event of erlotinib. We report the case of a 39-year-old man with erlotinib-induced interstitial lung disease in a non-small cell lung cancer patient. Although interstitial lung disease had improved by steroid therapy, palliative radiotherapy recalled the pneumonitis beyond the radiation fields. After the pneumonitis was well controlled, the patient was started on irinotecan, but the interstitial lung disease recurred shortly thereafter. We may have to abandon further cytotoxic therapies to avoid the recurrence of interstitial lung disease in patients who develop erlotinib-induced interstitial lung disease once.

A Phase II Study of Irinotecan for Patients with Previously Treated Small-Cell Lung Cancer

Objective: Chemotherapy with irinotecan plus cisplatin has shown promise in chemo-naïve small-cell lung cancer (SCLC) patients. However, irinotecan treatment for relapsed or refractory SCLC has not been adequately evaluated. This phase II study evaluated the appropriate treatment schedule of irinotecan as a single agent. This study was designed to determine the antitumor activity, toxicity, and survival in previously treated SCLC patients. Methods: Previously treated SCLC patients with at least one platinum-based regimen received irinotecan (100 mg/m2) on days 1 and 8, every 3 weeks, until disease progression. The assessment of the response rate was the primary endpoint. Results: Thirty patients were enrolled, with an objective response rate of 41.3% (95% confidence interval [CI] 25.5–59.3), and a disease control rate of 69%. Median progression-free and overall survival was 4.1 months (95% CI, 2.2–5.4) and 10.4 months (95% CI, 8.1–14), respectively. The grade 3/4 hematological toxicities were neutropenia (36.7%), thrombocytopenia (3.3%), anemia (13.3%), and febrile neutropenia (6.6%). There were no grade 4 nonhematological toxicities. Frequent grade 3 nonhematological toxicities included diarrhea (10%), anorexia (6.6%), and hyponatremia (6.6%). Conclusions: This phase II study showed a high objective response rate and long survival. Irinotecan monotherapy schedule used was well tolerated, and could be an active treatment option for these patients.

Transfer of in vitro-expanded naïve T cells after lymphodepletion enhances antitumor immunity through the induction of polyclonal antitumor effector T cells

The adoptive transfer of effector T cells combined with lymphodepletion has demonstrated promising antitumor effects in mice and humans, although the availability of tumor-specific T cells is limited. We and others have also demonstrated that the transfer of polyclonal naïve T cells induces tumor-specific effector T cells and enhances antitumor immunity after lymphodepletion. Because tumors have been demonstrated to induce immunosuppressive networks and regulate the function of T cells, obtaining a sufficient number of fully functional naïve T cells that are able to differentiate into tumor-specific effector T cells remains difficult. To establish culture methods to obtain a large number of polyclonal T cells that are capable of differentiating into tumor-specific effector T cells, naïve T cells were activated with anti-CD3 mAbs in vitro. These cells were stimulated with IL-2 and IL-7 for the CD8 subset or with IL-7 and IL-23 for the CD4 subset. Transfer of these hyperexpanded T cells after lymphodepletion showed significant antitumor efficacy, and tumor-specific effector T cells were primed from these expanded T cells in tumor-bearing hosts. Moreover, these ex vivo—expanded T cells maintained T cell receptor diversity and showed long-term persistence of memory against specific tumors. Further analyses revealed that combination therapy consisting of vaccination with dendritic cells that were co-cultured with irradiated whole tumor cells and the transfer of ex vivo—expanded T cells significantly enhanced antitumor immunity. These results indicate that the transfer of ex vivo—expanded polyclonal T cells can be combined with other immunotherapies and augment antitumor effects.

Abstract 3206: Programmed death receptor-1/programmed death receptor ligand-1 blockade improves priming of antitumor effector T cells after cytotoxic therapies

Cytotoxic lymphodepletion therapies, such as chemotherapy and radiotherapy, have been established to augment antitumor immunity. Naive T cells elicit effector-like phenotypes and functions during recovery from lymphopenia. We and others have repeatedly demonstrated that transfer of naive T cells into lymphopenic-tumor bearing mice delayed tumor growth. This enhancement of naive T cells is required an activation through T-cell receptor (TCR). Programmed death receptor-1 (PD-1)/programmed death receptor ligand-1 (PD-L1) blockade therapy has been demonstrated to augment antitumor immunity. Previous studies have shown that PD-1/PD-L1 blockade therapy stimulates or restores the function of antitumor T cells in the effector phase. Because engagement of programmed death receptor-1 (PD-1) by ligand suppresses TCR signaling and inhibits T cell activation and function, there is a possibility that PD-1 regulates activation of T cells during recovery from lymphopenia after cytotoxic therapies. In the current study, we transferred naive T cells into tumor-bearing mice following whole-body irradiation for lymphodepletion. These mice were further treated with anti-PD-1 antibodies. PD-1/PD-L1 blockade therapy after lymphodepletion significantly suppressed tumor progression. Next, we tested several kinds of cytotoxic agents to induce lymphopenia in mice. We found that the kind of cytotoxic agents affected the augmentation of antitumor efficacies of PD-1/PD-L1 blockade. Analyses of tumor-draining lymph-nodes (TDLNs) revealed that the number of tumor-specific effector T cells was significantly increased in mice treated with anti-PD-1 antibodies. By contrast, the number of effector T cells in spleens was not increased by PD-1/PD-L1 blockade therapy. These results indicate that PD-1 regulates a priming of antitumor effector T cells in TDLNs after cytotoxic lymphodepletion therapies. PD-1/PD-L1 blockade therapy is able to enhance antitumor T cell responses not only in the effector phase but also in the priming phase. Citation Format: Miho Takahashi, Satoshi Watanabe, Ko Sato, Tomohiro Tanaka, Yu Saida, Junko Baba, Aya Ohtsubo, Miyuki Sato, Rie Kondo, Masaaki Okajima, Junta Tanaka, Hiroshi Kagamu, Hirohisa Yoshizawa, Toshiaki Kikuchi. Programmed death receptor-1/programmed death receptor ligand-1 blockade improves priming of antitumor effector T cells after cytotoxic therapies. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3206.

Abstract 3153: Critical roles of chemo-resistant effector and regulatory T cells in cancer immunotherapy during hemostatic proliferation

Antitumor immunity has been well established to be augmented by cytotoxic lymphodepletion therapies. Adoptively transferred naive and effector T cells proliferate extensively and show enhanced antitumor effects during homeostatic proliferation when they were adoptively transferred into tumor-bearing hosts that were lymphodepleted with cytotoxic agents or by whole body irradiation. Although the impact of lymphodepletion on transferred donor T cells has been well evaluated, its influence on recipient T cells is largely unknown. The current study demonstrates that both regulatory T cells (Tregs) and effector CD8 + T cells from lymphopenic recipients play critical roles in the development of antitumor immunity after lymphodepletion. Cyclophosphamide (CPA) treatment depleted lymphocytes more efficiently than other cytotoxic agents, such as fludarabine, cisplatin, etoposide, paclitaxel or gemcitabine; however, the percentage of CD4 + CD25 + Foxp3 + Tregs was significantly increased in CPA-treated lymphopenic mice. Depletion of these chemo-resistant Tregs following CPA treatment and transfer of naive CD4 + T cells augmented the antitumor immunity and significantly suppressed tumor progression. Further analyses revealed that recipient CD8 + T cells were responsible for this augmentation. Using Rag2 −/− mice or depletion of recipient CD8 + T cells after CPA treatment abrogated the augmentation of antitumor effects in CPA-treated reconstituted mice. The transfer of donor CD4 + T cells enhanced the proliferation of CD8 + T cells and the priming of tumor-specific CD8 + T cells originating from the lymphopenic recipients. These results highlight the importance of the recipient cells surviving cytotoxic regimens in cancer immunotherapies. Citation Format: Ko Sato, Satoshi Watanabe, Yu Saida, Tomohiro Tanaka, Junko Baba, Aya Ohtsubo, Satoshi Shoji, Daisuke Ishikawa, Rie Kondo, Masaaki Okajima, Satoru Miura, Junta Tanaka, Hiroshi Kagamu, Hirohisa Yoshizawa, Ichiei Narita. Critical roles of chemo-resistant effector and regulatory T cells in cancer immunotherapy during hemostatic proliferation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3153. doi:10.1158/1538-7445.AM2015-3153

Abstract 2818: Dendritic cell vaccination and regulatory T-cell depletion augment antitumor immunity after cytotoxic therapy

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA The ability of lymphodepleting cytotoxic regimens to augment antitumor immune responses has been well established. We and others have previously reported that naive T cells, as well as effector T cells, transferred into lymphopenic tumor-bearing mice acquire memory-like phenotypes and show antitumor effects. The transfer of naive T cells into irradiated lymphopenic mice inhibited tumor progression. Further analyses revealed that the transfer of CD4+ naive T cells was essential for this augmentation of antitumor immunity after lymphodepletion. To enhance the antitumor efficacy of lymphodepletion and transfer of naive T cells, we have tested anti-CTLA-4 mAbs and anti-CD25 mAbs for depletion of regulatory T cells. Mice were irradiated with 500 cGy to deplete lymphocytes and were transferred i.v. with T cells (2 x 107). On the same day, mice were inoculated with MCA205 tumor cells (1 x 105) followed by the injection of anti-CTLA-4 mAbs (UC10) or the injection of anti-CD25 mAbs (PC61). Although the injection of anti-CTLA-4 mAbs showed minimal augmentation of the antitumor effects of the combination of lymphodepletion and naive T cell transfer, anti-CD25 mAbs significantly enhanced antitumor immune responses. Next, we evaluated whether dendritic cell vaccination augments this combination therapy. Different from previous experiments, 3-day tumor-bearing mice were irradiated and reconstituted with T cells. Dendritic cells were generated from bone marrow of naive mice and were co-cultured with irradiated MCA205 tumor cells followed by stimulation with agonistic anti-CD40 mAbs. We found that dendritic cell vaccination significantly inhibited tumor growth in irradiated reconstituted mice. Previously, we reported that a significant increase of CD4+CD25+Foxp3+ regulatory T cells in irradiated mice. We demonstrated that these radio-resistant regulatory T cells from irradiated recipient mice suppressed the development of antitumor immunity. To clarify the roles of other recipient cells in antitumor immunity during recovery from lymphopenia, Rag-2 knockout mice were irradiated and reconstituted with T cells. These mice were then inoculated MCA205 tumor cells. In Rag-2 knockout mice, antitumor effects were not observed after lymphodepletion and reconstitution. These findings indicate that recipient T cells or B cells were required to augment antitumor immunity in lymphopenic mice in our model. Citation Format: Tomohiro Tanaka, Satoshi Watanabe, Ko Sato, Yu Saida, Junko Baba, Koichiro Nozaki, Daisuke Ishikawa, Natsue Igarashi, Satoshi Shoji, Masaaki Okajima, Satoru Miura, Junta Tanaka, Hiroshi Tanaka, Hiroshi Kagamu, Hirohisa Yoshizawa, Ichiei Narita. Dendritic cell vaccination and regulatory T-cell depletion augment antitumor immunity after cytotoxic therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2818. doi:10.1158/1538-7445.AM2014-2818

Abstract 3963: Chemo-resistantregulatory T cells suppress the development of antitumor immunity aftercytotoxic regimens.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Previous studies demonstrated that naive T cells transferred into lymphopenic hosts develop into memory like T cells and acquire some effector functions. We and others have shown that sublethal whole body irradiation and transfer of naive T cells augment antitumor immunity and inhibited tumor progression. Further, we found a significant increase of CD4+CD25+Foxp3+ regulatory T cells (Treg) in irradiated mice. Depletion of those radio-resistant Treg after irradiation and transfer of naive T cells enhanced generation of antitumor effector T cells and suppressed tumor progression (Baba J, et al. 2012, Blood). The combination of lymphodepletion and transfer of naive T cells seems to be a promising strategy. However, whole body irradiation has not been routinely used in clinical settings. Previously, we demonstrated that the sublethal doses of cyclophosphamide (CPA) efficiently depleted lymphocytes in mice, and enhanced antitumor effects of transferred naive T cells. In this study, we examined the effect of lymphodepleting doses of CPA on immune suppressor cells. Similar to the irradiated lymphopenic hosts, a significant increase of Treg was observed in mice treated with CPA. The combination of CPA, transfer of naive T cells and Treg depletion with anti-CD25 monoclonal antibodies succeeded to cure advanced skin tumors.To evaluate the proliferation and apoptosis of Treg increasing in CPA-treated mice, we performed BrdU incorporation, Ki-67 expression and Annexin V apoptosis assay. The results indicated that the increased percentage of Treg during recovery from lymphopenia is due to the rapid proliferation of Treg that survive CPA treatment. Next, we investigated which subsets of donor T cells are necessary in this combination therapy. CD4+ or CD8+ T cells were depleted from donor T cells before transfer into lymphopenic skin tumor bearing mice. Depletion of CD4+ T cells, but not CD8+ T cells eliminated the antitumor effects. Intracellular cytokine FACS revealed that transfer of CD4+ T cells following CPA treatment induced tumor specific effector CD4+ T cells in lymphopenic hosts. Interestingly, transfer of CD4+ T cells also induced CD8+ effector T cells from CPA treated recipient cells. Depletion of CD8+ recipient cells with anti-CD8 monoclonal antibodies abrogated the antitumor effects of lymphodepletion and CD4+ T cells transfer. Furthermore, Transfer of CD4+ T cells into Rag-2 knockout mice showed no antitumor effects. These results suggested that donor CD4+ T cells induce effector CD8+ T cells originate from recipients after CPA treatment and suppress tumor progression. Our results showed that the combination of CPA treatment, naive CD4+ T cell transfer, and Treg depletion had potent antitumor efficacy. Both of donor CD4+ T cells and recipient CD8+ T cells were necessary for this augmentation of antitumor immunity. Citation Format: Yu Saida, Satoshi Watanabe, Tomohiro Tanaka, Junko Baba, Koh Satoh, Satoshi Shoji, Natsue Igarashi, Koichirou Nozaki, Masaaki Okajima, Satoru Miura, Junta Tanaka, Hiroshi Kagamu, Hirohisa Yoshizawa, Ichiei Narita. Chemo-resistantregulatory T cells suppress the development of antitumor immunity aftercytotoxic regimens. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3963. doi:10.1158/1538-7445.AM2013-3963