Generation of Tumor-Reactive T Cells by Co-culture of Peripheral Blood Lymphocytes and Tumor Organoids

Cancer immunotherapies have shown substantial clinical activity for a subset of patients with epithelial cancers. Still, technological platforms to study cancer T-cell interactions for individual patients and understand determinants of responsiveness are presently lacking. Here, we establish and validate a platform to induce and analyze tumor-specific T cell responses to epithelial cancers in a personalized manner. We demonstrate that co-cultures of autologous tumor organoids and peripheral blood lymphocytes can be used to enrich tumor-reactive T cells from peripheral blood of patients with mismatch repair-deficient colorectal cancer and non-small-cell lung cancer. Furthermore, we demonstrate that these T cells can be used to assess the efficiency of killing of matched tumor organoids. This platform provides an unbiased strategy for the isolation of tumor-reactive T cells and provides a means by which to assess the sensitivity of tumor cells to T cell-mediated attack at the level of the individual patient.

Targeting of cancer neoantigens with donor-derived T cell receptor repertoires

Accumulating evidence suggests that clinically efficacious cancer immunotherapies are driven by T cell reactivity against DNA mutation-derived neoantigens. However, among the large number of predicted neoantigens, only a minority is recognized by autologous patient T cells, and strategies to broaden neoantigen-specific T cell responses are therefore attractive. We found that naïve T cell repertoires of healthy blood donors provide a source of neoantigen-specific T cells, responding to 11 of 57 predicted human leukocyte antigen (HLA)-A*02:01-binding epitopes from three patients. Many of the T cell reactivities involved epitopes that in vivo were neglected by patient autologous tumor-infiltrating lymphocytes. Finally, T cells redirected with T cell receptors identified from donor-derived T cells efficiently recognized patient-derived melanoma cells harboring the relevant mutations, providing a rationale for the use of such "outsourced" immune responses in cancer immunotherapy.

Effective Clinical Responses in Metastatic Melanoma Patients after Vaccination with Primary Myeloid Dendritic Cells

PURPOSE

Thus far, dendritic cell (DC)-based immunotherapy of cancer was primarily based on in vitro-generated monocyte-derived DCs, which require extensive in vitro manipulation. Here, we report on a clinical study exploiting primary CD1c(+) myeloid DCs, naturally circulating in the blood.

EXPERIMENTAL DESIGN

Fourteen stage IV melanoma patients, without previous systemic treatment for metastatic disease, received autologous CD1c(+) myeloid DCs, activated by only brief (16 hours) ex vivo culture and loaded with tumor-associated antigens of tyrosinase and gp100.

RESULTS

Our results show that therapeutic vaccination against melanoma with small amounts (3-10 × 10(6)) of myeloid DCs is feasible and without substantial toxicity. Four of 14 patients showed long-term progression-free survival (12-35 months), which directly correlated with the development of multifunctional CD8(+) T-cell responses in three of these patients. In particular, high CD107a expression, indicative for cytolytic activity, and IFNγ as well as TNFα and CCL4 production was observed. Apparently, these T-cell responses are essential to induce tumor regression and promote long-term survival by stalling tumor growth.

CONCLUSIONS

We show that vaccination of metastatic melanoma patients with primary myeloid DCs is feasible and safe and results in induction of effective antitumor immune responses that coincide with improved progression-free survival. Clin Cancer Res; 22(9); 2155-66. ©2015 AACR.

Abstract 4704: Neo-antigen enriched TIL therapy mediates superior tumor eradication in a patient-derived xenograft model of human melanoma

The mutational load in melanoma is high relative to that in most other human malignancies, resulting in the possible expression of large numbers of patient-specific mutated antigens. This may, in part, explain the immunogenicity of this disease and the high rate of responsiveness to immunotherapeutic strategies such as tumor-infiltrating lymphocyte (TIL) therapy. Indeed, recent data have shown that cytotoxic T-cell reactivity targeting neo antigens may be common in human melanoma TILs. Importantly though, the clinical relevance of neo-antigen specific T cell populations remains uncertain.

To directly address the tumoricidal potential of defined neo-antigen specific T cell populations, we first identified two neo-antigen specific T-cell populations within a bulk melanoma TIL culture by the combination of exome sequencing and MHC multimer-based T cell screens. Subsequently, we generated TIL products that are highly enriched for these neo-antigen reactivities and we compared the anti-tumor activity of these neo-antigen enriched TIL with that of ‘standard’ bulk TIL in NSG mice bearing the autologous tumor. We observed outgrowth of the tumors in mice treated with standard TIL. In contrast, tumors in mice treated with enriched TILs were controlled long-term. Additional experiments showed that this superior activity of neo-antigen enriched TIL was caused by the increased numbers of T cells with a high anti-tumor activity, rather than the depletion of cell populations with inhibitory activity. Furthermore, once tumors eventually recurred these were still recognized in vitro by cells from the initially infused TIL culture.

Together, these preclinical data demonstrate that neo-antigen reactive T cells within bulk TIL cultures form a critical component of anti-tumor reactivity and provide a further basis to target mutated antigens with cancer immunotherapy.

Citation Format: Sander Kelderman, Laura Bies, Marit M. Van Buuren, Nienke Van Rooij, John Haanen, Pia Kvistborg, Ton Schumacher. Neo-antigen enriched TIL therapy mediates superior tumor eradication in a patient-derived xenograft model of human melanoma. [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 4704. doi:10.1158/1538-7445.AM2015-4704

Reversibility of pulmonary function after inhaling salbutamol in different doses and body postures in asthmatic children

RATIONALE

Pulmonary medication is often delivered in the form of medical aerosols designed for inhalation. Recently, breath actuated inhalers (BAI's) gained popularity as they can be used without spacers. A major drawback of BAI's is the impaction in the upper airway. Stretching the upper airway by a forward leaning body posture with the neck extended ("sniffing position") during inhalation may reduce upper airway impaction and improve pulmonary deposition. Aim of this study was to investigate the reversibility of lung function with different doses salbutamol inhaled with a BAI in the forward leaning posture compared to the standard posture in asthmatic children.

METHODS

22 clinically stable asthmatic children, 5-14 years old, performed four reversibility measurements. Children inhaled 200 μg or 400 μg salbutamol with a BAI in the standard or in the forward leaning posture with the neck extended in a randomized single-blinded cross-over design.

RESULTS

Reversibility of lung function after inhaling salbutamol in the forward leaning posture was not significantly different compared to inhalation in the standard posture. Mean FEV1 reversibility was significantly greater after inhaling 400 μg salbutamol compared to 200 μg salbutamol in the standard posture (9.4% ± 9.5% versus 4.5% ± 7.5%, difference 4.9% (95CI 0.9; 9.0%); p = 0.021).

CONCLUSION

In clinically stable asthmatic children, inhalation of salbutamol with a BAI in a forward leaning posture does not increase reversibility of lung function. Inhalation of 400 μg compared to 200 μg salbutamol with a BAI does improve reversibility.

Mismatch Repair-Deficient Cancers Are Targets for Anti-PD-1 Therapy

Immune checkpoint-blocking therapies have yielded positive clinical data in a series of human malignancies. Recent work from Le and colleagues strongly supports the use of these therapies for mismatch repair-deficient tumors, independent of underlying tumor type. These data suggest the importance of sensing the consequences of DNA damage in cancer immunotherapy.

Anti-CTLA-4 therapy broadens the melanoma-reactive CD8+ T cell response

Anti-CTLA-4 treatment improves the survival of patients with advanced-stage melanoma. However, although the anti-CTLA-4 antibody ipilimumab is now an approved treatment for patients with metastatic disease, it remains unknown by which mechanism it boosts tumor-specific T cell activity. In particular, it is unclear whether treatment amplifies previously induced T cell responses or whether it induces new tumor-specific T cell reactivities. Using a combination ultraviolet (UV)-induced peptide exchange and peptide-major histocompatibility complex (pMHC) combinatorial coding, we monitored immune reactivity against a panel of 145 melanoma-associated epitopes in a cohort of patients receiving anti-CTLA-4 treatment. Comparison of pre- and posttreatment T cell reactivities in peripheral blood mononuclear cell samples of 40 melanoma patients demonstrated that anti-CTLA-4 treatment induces a significant increase in the number of detectable melanoma-specific CD8 T cell responses (P = 0.0009). In striking contrast, the magnitude of both virus-specific and melanoma-specific T cell responses that were already detected before start of therapy remained unaltered by treatment (P = 0.74). The observation that anti-CTLA-4 treatment induces a significant number of newly detected T cell responses-but only infrequently boosts preexisting immune responses-provides strong evidence for anti-CTLA-4 therapy-enhanced T cell priming as a component of the clinical mode of action.

Acquired and intrinsic resistance in cancer immunotherapy

A number of immunotherapies, in particular immune checkpoint targeting antibodies and adoptive T-cell therapies, are starting to transform the treatment of advanced cancers. The likelihood to respond to these immunotherapies differs strongly across tumor types, with response rates for checkpoint targeting being the highest in advanced melanoma, renal cell cancer and non-small cell lung cancer. However, also non-responsiveness is observed, indicating the presence of intrinsic resistance or naturally acquired resistance. In addition, a subgroup of patients that do initially respond to immunotherapy will later recur, thereby also pointing towards a role of therapy-induced acquired resistance. Here, we review our current understanding of both intrinsic and acquired resistance mechanisms in cancer immunotherapy, and discuss potential strategies to overcome them.

Lactate dehydrogenase as a selection criterion for ipilimumab treatment in metastatic melanoma

INTRODUCTION

Ipilimumab, a cytotoxic T lymphocyte-associated antigen-4 blocking antibody, has improved overall survival (OS) in metastatic melanoma in phase III trials. However, about 80 % of patients fail to respond, and no predictive markers for benefit from therapy have been identified. We analysed a 'real world' population of patients treated with ipilimumab to identify markers for treatment benefit.

METHODS

Patients with advanced cutaneous melanoma were treated in the Netherlands (NL) and the United Kingdom (UK) with ipilimumab at 3 mg/kg. Baseline characteristics and peripheral blood parameters were assessed, and patients were monitored for the occurrence of adverse events and outcomes.

RESULTS

A total of 166 patients were treated in the Netherlands. Best overall response and disease control rates were 17 and 35 %, respectively. Median follow-up was 17.9 months, with a median progression-free survival of 2.9 months. Median OS was 7.5 months, and OS at 1 year was 37.8 % and at 2 years was 22.9 %. In a multivariate model, baseline serum lactate dehydrogenase (LDH) was demonstrated to be the strongest predictive factor for OS. These findings were validated in an independent cohort of 64 patients from the UK.

CONCLUSION

In both the NL and UK cohorts, long-term benefit of ipilimumab treatment was unlikely for patients with baseline serum LDH greater than twice the upper limit of normal. In the absence of prospective data, clinicians treating melanoma may wish to consider the data presented here to guide patient selection for ipilimumab therapy.

Dissection of anti-CTLA4-induced cytotoxic T-cell responses in melanoma

9078

Background: There is strong evidence that melanoma-reactive T cells induced by immunotherapeutic interventions such as anti-CTLA4 therapy can exert clinically effects. However, there is very little information on how these therapies influence tumor-specific T cell responses. Furthermore, as the number of potential melanoma-associated antigens to which these responses can be directed is very high, classical strategies to map cytotoxic T cell reactivity do not suffice. Knowledge of such reactivities would be useful to design targeted strategies, selectively aiming to induce immune reactivity against these antigens. Methods: We have addressed these issues by designing MHC class I molecules occupied with UV-sensitive ‘conditional’ ligands, thereby allowing the production of very large collections of pMHC complexes for T cell detection. Secondly, we have developed a ‘combinatorial coding’ strategy that allows parallel detection of dozens of different T cell populations within a single sample. The combined use of MHC ligand exchange and combinatorial coding allows the high-throughput dissection of disease- and therapy-induced CTL immunity. We have used this platform to monitor immune reactivity against a panel of 145 melanoma-associated epitopes in patients receiving Ipilimumab treatment. Results: Comparison of PBMC samples from 32 melanoma patients pre- and post-therapy indicated a significant increase in the number of detectable melanoma-associated T cell responses (p=0.004). Furthermore, kinetic data on T cell responses during therapy suggests that this broadening generally occurs within weeks after start of therapy. The magnitude of melanoma-specific T cell responses that was detectable prior to start of therapy was not significantly altered (p=0.8). Conclusions: These results establish the pattern of melanoma-specific T-cell reactivity induced by anti-CTLA4 treatment and form a benchmark for evaluation of other immunotherapeutic interventions, like anti-PD1 treatment, that are currently undergoing clinical evaluation. Furthermore, our data suggests that the clinical activity of Ipilimumab may be mostly due to epitope spreading, rather than through enhancement of pre-existing immune activity.

Serum lactate dehydrogenase (LDH) as a prognostic selection criterion for ipilimumab treatment in metastatic melanoma

3036

Background: Ipilimumab, a CTLA4 blocking antibody, has been shown to improve survival in metastatic melanoma patients in phase III trials. However, only a subset of patients experiences long-term survival benefit. Therefore, we analysed two independent retrospective sets of patients treated in ‘real world’ settings to identify prognostic factors that correlate with better outcome after ipilimumab therapy. Methods: Advanced melanoma patients, eligible for ipilimumab therapy, were treated in the Dutch and UK Expanded Access Programs (EAP) and after European licensing on the 3mg/kg schedule. Baseline characteristics and peripheral blood parameters were assessed and patients were monitored for the occurrence of adverse events and responses. Results: A total of 166 patients were enrolled in the Dutch EAP. Best overall response rate and disease control rate were (DCR) 17% and 35%. Median follow-up was 17.9 months, with a median progression free survival of 2.9 months. Median overall survival (OS) was 7.5 months, and OS at 1 year 37.8% and at 2 years 22.9%. Univariate analysis revealed that gender, age, Breslow thickness, baseline and week 6 lymphocyte count (ALC), and prior treatment had no influence on OS, while mWHO, M stage, baseline LDH, S100, erythrocyte sedimentation rate (ESR), and the slope of ALC did. In a multivariate model only baseline LDH and ESR remained as significant independent prognostic factors. The relevance of LDH was validated in an independent cohort of 68 patients from the UK. Stratifying the patients in the NL cohort according to LDH levels (≤upper limit normal (ULN), 54.4% of patients versus >2xULN, 16.9% of patients) separated into groups of patients observing DCR of 48% versus 14%, and median OS of 13.7 versus 3.1 months, while toxicity was similar in both groups (48% and 41%). None of the patients was alive at 15 months after treatment if baseline LDH was >2xULN in both the NL and UK cohorts. Conclusions: Overall survival upon ipilimumab treatment is lower in an expanded access population as compared to phase III trials. LDH >2xULN at baseline is a potential prognosticator in patients receiving ipilimumab and should be considered in guiding ipilimumab treatment initiation.

A universal strategy for adoptive immunotherapy of cancer through use of a novel T-cell antigen receptor

Adoptive immunotherapies composed of T cells engineered to express a chimeric antigen receptor (CAR) offer an attractive strategy for treatment of human cancer. However, CARs have a fixed antigen specificity such that only one tumor-associated antigen (TAA) can be targeted, limiting the efficacy that can be achieved because of heterogeneous TAA expression. For this reason, a more generalized and effective application of CAR therapy would benefit from the capability to produce large panels of CARs against many known TAAs. In this study, we show a novel strategy to extend the recognition specificity potential of a bioengineered lymphocyte population, allowing flexible approaches to redirect T cells against various TAAs. Our strategy employs a biotin-binding immune receptor (BBIR) composed of an extracellular-modified avidin linked to an intracellular T-cell signaling domain. BBIR T cells recognized and bound exclusively to cancer cells pretargeted with specific biotinylated molecules. The versatility afforded by BBIRs permitted sequential or simultaneous targeting of a combination of distinct antigens. Together, our findings show that a platform of universal T-cell specificity can significantly extend conventional CAR approaches, permitting the tailored generation of T cells of unlimited antigen specificity for improving the effectiveness of adoptive T-cell immunotherapies for cancer.

[Sternoclavicular joint tuberculosis]

A 24-year old woman presented with an abscess localized at the median side of the right clavicle. There were no clinical signs of tuberculosis and radiological evaluation was normal. PCR-assay on tuberculosis following aspiration of the pus collection was positive for Mycobacterium tuberculosis. She responded well on regular anti-tuberculosis treatment.