Control of minimal residual cancer by low dose ipilimumab activating autologous anti-tumor immunity

Tackling cancer cell dormancy: Insights from immune models, and transplantation

Disseminated non-dividing (dormant) cancer cells as well as those in equilibrium with the immune response remain the major challenge for successful treatment of cancer. The equilibrium between disseminated dormant cancer cells and the immune system is reminiscent of states that can occur during infection or allogeneic tissue and cell transplantation. We discuss here the major competing models of how the immune system achieves a self nonself discrimination (pathogen/danger patterns, quorum, and coinhibition/tuning models), and suggest that taking advantage of a combination of the proposed mechanisms in each model may lead to increased efficacy in tackling cancer cell dormancy.

Low-dose ipilimumab plus nivolumab combined with IL-2 and hyperthermia in cancer patients with advanced disease: exploratory findings of a case series of 131 stage IV cancers - a retrospective study of a single institution

The 3-year overall survival (OS) rate of patients with previously treated or untreated stage III or IV melanoma has by now reached 63% using ipilimumab and nivolumab therapy. However, immune-related adverse events (irAEs) of grade 3 or 4 occurred in 59% of patients leading to discontinuation of therapy in 24.5% of patients and one death. Therapy with checkpoint inhibitors could be safer and more effective in combination with hyperthermia and fever inducing therapies. We conducted a retrospective analysis to test the safety and efficacy of a new combination immune therapy in 131 unselected stage IV solid cancer patients with 23 different histological types of cancer who exhausted all conventional treatments. Treatment consisted of locoregional- and whole-body hyperthermia, individually dose adapted interleukin 2 (IL-2) combined with low-dose ipilimumab (0.3 mg/kg) plus nivolumab (0.5 mg/kg). The objective response rate (ORR) was 31.3%, progression-free survival (PFS) was 10 months, survival probabilities at 6 months was 86.7% (95% CI, 81.0–92.8%), at 9 months was 73.5% (95% CI, 66.2–81.7%), at 12 months was 66.5% (95% CI, 58.6–75.4%), while at 24 months survival was 36.6% (95% CI:28.2%; 47.3%). irAEs of World Health Organization (WHO) Toxicity Scale grade 1, 2, 3, and 4 were observed in 23.66%, 16.03%, 6.11%, and 2.29% of patients, respectively. Our results suggest that the irAEs profile of the combined treatment is safer than that of the established protocols without compromising efficacy.

Significant association between tumor mutational burden and immune-related adverse events during immune checkpoint inhibition therapies

More than 2000 immuno-oncology agents are being tested or are in use as a result of the cancer immunotherapy revolution. Manipulation of co-inhibitory receptors has achieved tumor eradication in a minority of patients, but widespread immune-related adverse events (irAEs) compromised tolerance to healthy self-tissues in the majority. We have proposed that a major mechanism of irAEs is similar to a graft-versus-malignancy effect of graft-versus-host disease. To verify our hypothesis, we retrieved post-marketing data of adverse events from the U.S. Food and Drug Administration Adverse Event Reporting System. A significant positive correlation was revealed in 7677 patients between the reporting odds ratio of irAEs during immune checkpoint inhibitor therapy and the corresponding tumor mutational burden across 19 cancer types. These results can be interpreted to mean that the ICI drugs unleashed T cells against “altered-self,” self, and tumors resulting in better overall survival.

Exploiting autoimmunity unleashed by low-dose immune checkpoint blockade to treat advanced cancer

As a result of the cancer immunotherapy revolution, more than 2000 immuno-oncology agents are currently being tested or are in use to improve responses. Not unexpectedly, the 2018 Nobel Prize in Physiology or Medicine was awarded to James P. Allison and Tasuku Honjo for their development of cancer therapy by the blockade of co-inhibitory signals. Unfortunately, manipulation of the co-inhibitory receptors has also resulted in a safety issue: widespread iatrogenic immune-related adverse events (irAEs). Autoimmunity is emerging as the nemesis of immunotherapy. Originally, it was assumed that CTLA-4 blockade selectively targets T cells relevant to the antitumour immune response. However, an uncontrolled pan T cell activation was induced compromising tolerance to healthy self-tissues. The irAEs are very similar to that of a chronic graft-versus-host-disease (GVHD) reaction following allogeneic bone marrow transplantation (BMT). We hypothesized that ipilimumab induced a graft-versus-malignancy (GVM) effect, which eradicated metastatic melanoma in a minority of patients, but also involved an auto-GVHD reaction that resulted in widespread autoimmunity in the majority. Therefore, we argued for a profound theoretical point against the consensus of experts. The task is not to desperately put the genie back in the bottle by immune-suppressive treatments, but instead to harness the autoimmune forces. In this way, the same goal could be achieved by an antibody as by the adoptive transfer of alloreactive donor lymphocytes, but without severe GVHD. The proof-of-principle of a low-dose-combination immune checkpoint therapy, consisting only of approved drugs and treatments, was demonstrated in 111 stage IV cancer patients.

MiStImm: an agent-based simulation tool to study the self-nonself discrimination of the adaptive immune response

BACKGROUND

There is an increasing need for complex computational models to perform in silico experiments as an adjunct to in vitro and in vivo experiments in immunology. We introduce Microscopic Stochastic Immune System Simulator (MiStImm), an agent-based simulation tool, that is designed to study the self-nonself discrimination of the adaptive immune system. MiStImm can simulate some components of the humoral adaptive immune response, including T cells, B cells, antibodies, danger signals, interleukins, self cells, foreign antigens, and the interactions among them. The simulation starts after conception and progresses step by step (in time) driven by random simulation events. We also have provided tools to visualize and analyze the output of the simulation program.

RESULTS

As the first application of MiStImm, we simulated two different immune models, and then we compared performances of them in the mean of self-nonself discrimination. The first model is a so-called conventional immune model, and the second model is based on our earlier T-cell model, called "one-signal model", which is developed to resolve three important paradoxes of immunology. Our new T-cell model postulates that a dynamic steady state coupled system is formed through low-affinity complementary TCR-MHC interactions between T cells and host cells. The new model implies that a significant fraction of the naive polyclonal T cells is recruited into the first line of defense against an infection. Simulation experiments using MiStImm have shown that the computational realization of the new model shows real patterns. For example, the new model develops immune memory and it does not develop autoimmune reaction despite the hypothesized, enhanced TCR-MHC interaction between T cells and self cells. Simulations also demonstrated that our new model gives better results to overcome a critical primary infection answering the paradox "how can a tiny fraction of human genome effectively compete with a vastly larger pool of mutating pathogen DNA?"

CONCLUSION

The outcomes of our in silico experiments, presented here, are supported by numerous clinical trial observations from the field of immunotherapy. We hope that our results will encourage investigations to make in vitro and in vivo experiments clarifying questions about self-nonself discrimination of the adaptive immune system. We also hope that MiStImm or some concept in it will be useful to other researchers who want to implement or compare other immune models.

Complete Clinical Remission of Stage IV Triple-Negative Breast Cancer Lung Metastasis Administering Low-Dose Immune Checkpoint Blockade in Combination With Hyperthermia and Interleukin-2

The prognosis of triple-negative breast cancer with metastases after chemotherapy remains dismal. We report the case of a 50-year-old female with first disease recurrence at the axillary lymph node and, later on, bilateral pulmonary metastases with severe shortness of breath. The patient received low-dose immune checkpoint blockade (concurrent nivolumab and ipilimumab) weekly over 3 weeks with regional hyperthermia 3 times a week, followed by systemic fever-range hyperthermia induced by interleukin-2 for 5 days. She went into complete remission of her pulmonary metastases with transient WHO I-II diarrhea and skin rash. The patient remained alive for 27 months after the start of treatment, with recurrence of metastases as a sternal mass, and up to 3 cm pleural metastases. This exceptional response should instigate further research efforts with this protocol, which consists only of approved drugs and treatments.

Direct confirmation of quiescence of CD34+CD38- leukemia stem cell populations using single cell culture, their molecular signature and clinicopathological implications

Background

The proliferating activity of a single leukemia stem cell and the molecular mechanisms for their quiescent property remain unknown, and also their prognostic value remains a matter of debate. Therefore, this study aimed to demonstrate the quiescence property and molecular signature of leukemia stem cell and their clinicopathological implications.

Methods

Single cell sorting and culture were performed in the various sets of hematopoietic stem cells including CD34+CD38- acute myeloid leukemia (AML) cell population (ASCs) from a total of 60 patients with AML, and 11 healthy controls. Their quiescence related-molecular signatures and clinicopathological parameters were evaluated in AML patients.

Results

Single cell plating efficiency of ASCs was significantly lower (8.6%) than those of normal hematopoietic stem cells i.e.: cord blood, 79.0%; peripheral blood, 45.3%; and bone marrow stem cell, 31.1%. Members of the TGFβ super-family signaling pathway were most significantly decreased; as well as members of the Wnt, Notch, pluripotency maintenance and hedgehog pathways, compared with non ASC populations. mtDNA copy number of ASCs was significantly lower than that of corresponding other cell populations. However, our data couldn’t support the prognostic value of the ASCs in AML.

Conclusions

ASCs showed remarkable lower plating efficiency and slower dividing properties at the single cell level. This quiescence is represented as a marked decrease in the mtDNA copy number and also linked with down-regulation of genes in various molecular pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1233-x) contains supplementary material, which is available to authorized users.

Anti-CTLA-4 therapy may have mechanisms similar to those occurring in inherited human CTLA4 haploinsufficiency

The inhibitory anti-CTLA-4 antibody, ipilimumab, dramatically improved survival in a subgroup of metastatic melanoma patients. The majority, however, suffered autoimmune-related adverse events (irAEs), sometimes pathognomonic of acute graft-versus-host-disease (GVHD). This implies that the CTLA-4 blockade is not tumor specific. We make a risky but testable prediction: anti-CTLA-4 therapy may have mechanism similar to that occurring in inherited human CTLA-4 haploinsufficiency. If so, a therapeutic paradigm shift is required. The task is not desperately trying to put the genie back in the bottle by immune-suppressive treatments, but harnessing the immense forces liberated by the anti-CTLA-4 antibody blockade by pretargeting or dose adjustment.