SITC cancer immunotherapy resource document: a compass in the land of biomarker discovery.

Since the publication of the Society for Immunotherapy of Cancer's (SITC) original cancer immunotherapy biomarkers resource document, there have been remarkable breakthroughs in cancer immunotherapy, in particular the development and approval of immune checkpoint inhibitors, engineered cellular therapies, and tumor vaccines to unleash antitumor immune activity. The most notable feature of these breakthroughs is the achievement of durable clinical responses in some patients, enabling long-term survival. These durable responses have been noted in tumor types that were not previously considered immunotherapy-sensitive, suggesting that all patients with cancer may have the potential to benefit from immunotherapy. However, a persistent challenge in the field is the fact that only a minority of patients respond to immunotherapy, especially those therapies that rely on endogenous immune activation such as checkpoint inhibitors and vaccination due to the complex and heterogeneous immune escape mechanisms which can develop in each patient. Therefore, the development of robust biomarkers for each immunotherapy strategy, enabling rational patient selection and the design of precise combination therapies, is key for the continued success and improvement of immunotherapy. In this document, we summarize and update established biomarkers, guidelines, and regulatory considerations for clinical immune biomarker development, discuss well-known and novel technologies for biomarker discovery and validation, and provide tools and resources that can be used by the biomarker research community to facilitate the continued development of immuno-oncology and aid in the goal of durable responses in all patients.

Emerging concepts in biomarker discovery; the US-Japan Workshop on Immunological Molecular Markers in Oncology.

Supported by the Office of International Affairs, National Cancer Institute (NCI), the "US-Japan Workshop on Immunological Biomarkers in Oncology" was held in March 2009. The workshop was related to a task force launched by the International Society for the Biological Therapy of Cancer (iSBTc) and the United States Food and Drug Administration (FDA) to identify strategies for biomarker discovery and validation in the field of biotherapy. The effort will culminate on October 28th 2009 in the "iSBTc-FDA-NCI Workshop on Prognostic and Predictive Immunologic Biomarkers in Cancer", which will be held in Washington DC in association with the Annual Meeting. The purposes of the US-Japan workshop were a) to discuss novel approaches to enhance the discovery of predictive and/or prognostic markers in cancer immunotherapy; b) to define the state of the science in biomarker discovery and validation. The participation of Japanese and US scientists provided the opportunity to identify shared or discordant themes across the distinct immune genetic background and the diverse prevalence of disease between the two Nations. Converging concepts were identified: enhanced knowledge of interferon-related pathways was found to be central to the understanding of immune-mediated tissue-specific destruction (TSD) of which tumor rejection is a representative facet. Although the expression of interferon-stimulated genes (ISGs) likely mediates the inflammatory process leading to tumor rejection, it is insufficient by itself and the associated mechanisms need to be identified. It is likely that adaptive immune responses play a broader role in tumor rejection than those strictly related to their antigen-specificity; likely, their primary role is to trigger an acute and tissue-specific inflammatory response at the tumor site that leads to rejection upon recruitment of additional innate and adaptive immune mechanisms. Other candidate systemic and/or tissue-specific biomarkers were recognized that might be added to the list of known entities applicable in immunotherapy trials. The need for a systematic approach to biomarker discovery that takes advantage of powerful high-throughput technologies was recognized; it was clear from the current state of the science that immunotherapy is still in a discovery phase and only a few of the current biomarkers warrant extensive validation. It was, finally, clear that, while current technologies have almost limitless potential, inadequate study design, limited standardization and cross-validation among laboratories and suboptimal comparability of data remain major road blocks. The institution of an interactive consortium for high throughput molecular monitoring of clinical trials with voluntary participation might provide cost-effective solutions.

A systematic approach to biomarker discovery; preamble to "the iSBTc-FDA taskforce on immunotherapy biomarkers".

The International Society for the Biological Therapy of Cancer (iSBTc) has initiated in collaboration with the United States Food and Drug Administration (FDA) a programmatic look at innovative avenues for the identification of relevant parameters to assist clinical and basic scientists who study the natural course of host/tumor interactions or their response to immune manipulation. The task force has two primary goals: 1) identify best practices of standardized and validated immune monitoring procedures and assays to promote inter-trial comparisons and 2) develop strategies for the identification of novel biomarkers that may enhance our understating of principles governing human cancer immune biology and, consequently, implement their clinical application. Two working groups were created that will report the developed best practices at an NCI/FDA/iSBTc sponsored workshop tied to the annual meeting of the iSBTc to be held in Washington DC in the Fall of 2009. This foreword provides an overview of the task force and invites feedback from readers that might be incorporated in the discussions and in the final document.

Dissociated production of perforin, granzyme B, and IFN-gamma by HIV-specific CD8(+) cells in HIV infection.

CD8(+) T cells play a crucial role in the control of viral infections such as HIV. The functional characterization of HIV-specific CD8(+) T cells has so far been largely restricted to studies of IFN-gamma. The TCR-triggered release of the effector molecules perforin (PFN) and granzyme B (GzB), however, is thought to be a central pathway for the destruction of virus-infected target cells by CD8(+) effector T cells. Here we would like to address two major findings. On the one hand we propose that ex vivo measurements of PFN and GzB secretion via ELISPOT may permit the distinction between in vivo resting versus activated CD8(+) memory T cells in healthy and HIV-infected individuals. Therefore, extending the present standard of IFN-gamma measurements to the analysis of PFN and GzB release in functional T cell assays will provide new insights into CD8(+) effector T cell functions. It should enable the evaluation of therapeutic vaccination efficacy by its ability to reactivate and convert IFN-gamma-positive, but GzB- and PFN-negative memory CD8(+) T cells into PFN/GzB-secreting effector cells. On the other hand, we report on a frequent ex vivo dissociation of the HIV peptide-induced secretion of PFN and GzB in chronic HIV infection underlining CD8(+) effector T cell diversity in this disease--an aspect that also has to be accounted for in immune monitoring approaches.

Novel technologies and emerging biomarkers for personalized cancer immunotherapy.

The culmination of over a century's work to understand the role of the immune system in tumor control has led to the recent advances in cancer immunotherapies that have resulted in durable clinical responses in patients with a variety of malignancies. Cancer immunotherapies are rapidly changing traditional treatment paradigms and expanding the therapeutic landscape for cancer patients. However, despite the current success of these therapies, not all patients respond to immunotherapy and even those that do often experience toxicities. Thus, there is a growing need to identify predictive and prognostic biomarkers that enhance our understanding of the mechanisms underlying the complex interactions between the immune system and cancer. Therefore, the Society for Immunotherapy of Cancer (SITC) reconvened an Immune Biomarkers Task Force to review state of the art technologies, identify current hurdlers, and make recommendations for the field. As a product of this task force, Working Group 2 (WG2), consisting of international experts from academia and industry, assembled to identify and discuss promising technologies for biomarker discovery and validation. Thus, this WG2 consensus paper will focus on the current status of emerging biomarkers for immune checkpoint blockade therapy and discuss novel technologies as well as high dimensional data analysis platforms that will be pivotal for future biomarker research. In addition, this paper will include a brief overview of the current challenges with recommendations for future biomarker discovery.

Recipient-specific tolerance after HLA-mismatched umbilical cord blood stem cell transplantation.

BACKGROUND: Lower incidence and severity of acute graft versus host disease (GVHD) has been observed in leukemia patients receiving HLA-mismatched umbilical cord (UCB) transplants. However, despite the increased use of UCB in stem cell transplantation, the mechanisms underlying these favorable outcomes are not well delineated. METHODS: We analyzed antigen specific lymphocyte responses after transplant to determine whether the decreased allogeneic responsiveness of UCB lymphocytes is attributable to pan-unresponsiveness, lymphocyte repressive or recipient-specific tolerance. RESULTS: Circulating lymphocytes collected early (3 months) after UCB transplant demonstrate a less naïve phenotype compared with that in the infused graft. Additionally, after transplant, circulating peripheral blood UCB-derived lymphocytes produced normal levels of interferon-gamma and proliferated normally when stimulated with mitogen or third party alloantigen. In contrast, when stimulated with recipient antigen, circulating lymphocytes emerging posttransplant did not proliferate nor produce interferon-gamma. Moreover, analysis of interleukin-4 production revealed a Th2 response to recipient antigens. These data indicate early induction of immune tolerance of naïve UCB graft lymphocytes with skewing of transplant recipient-specific immune response towards Th2 cytokine profile. CONCLUSIONS: UCB graft lymphocyte immune naivety and observed early tolerance induction may contribute to the observed favorable GVHD incidence, despite infusion of HLA mismatch grafts in the unrelated allogeneic setting.

Tc1 effector diversity shows dissociated expression of granzyme B and interferon-gamma in HIV infection.

OBJECTIVE: To examine antigen specific cytotoxic effector T cell diversity in HIV infected individuals. DESIGN: We used a panel of previously defined HLA class I-restricted HIV peptides to stimulate CD8 cells in freshly isolated peripheral blood mononuclear cells of HIV infected patients, to determine cognate killing via the perforin-granzyme pathway and inflammation induced by secretion of interferon (IFN)-gamma. METHODS: ELISPOT assays were used to measure the secretion of granzyme B (GzB) and IFN-gamma at single cell resolution. RESULTS: In all nine patients only approximately 20% of the peptides triggered a canonical Tc1 response with simultaneous release of GzB and IFN-gamma. The majority of these peptides (approximately 80%) that elicited recall responses fell into the 'single positive' category with induction of either GzB or IFN-gamma alone. The GzB positive cells did not produce interleukin (IL)-4 or IL-5. CONCLUSION: The GzB positive but IFN-gamma negative CD8 cells are programmed to induce apoptosis mediated killing without inflammation while the GzB negative and IFN-gamma positive CD8 cells could mediate inflammation without killing. This Tc1 CD8 effector cell diversity and the understanding of these differentiation mechanisms may enable the precise implementation and fine-tuning of fundamentally different defense strategies against HIV and other infections.