Selective CD4+ lymphopenia in melanoma patients treated with temozolomide: a toxicity with therapeutic implications

Severe pneumocystis jiroveci pneumonia in a patient on temozolomide therapy: A case report and review of literature

A 66 year old man was diagnosed with CNS diffuse large B-cell lymphoma, and underwent treatment with Temozolomide, Dexamethasone, Rituximab, and radiation therapy, and prolonged steroid taper with Dexamethasone. Approximately one month after this, he presented with severe acute hypoxemic respiratory failure, and was admitted to the Medical Intensive Care Unit. Imaging showed diffuse ground glass opacities. Patient underwent diagnostic bronchoalveolar lavage which was positive for Pneumocystis jiroveci. He did not respond well to appropriate therapy and was transitioned to comfort care per his family's wishes, and expired. Pneumocystis jiroveci should always be included in the differential diagnosis of pneumonia in patients treated with Temozolomide, especially when this agent is used in combination with long term, high dose corticosteroids and radiation therapy.

In-depth immunophenotyping of patients with glioblastoma multiforme: Impact of steroid treatment

Despite aggressive treatment regimens based on surgery and radiochemotherapy, the prognosis of patients with grade IV glioblastoma multiforme (GBM) remains extremely poor, calling for alternative options such as immunotherapy. Immunological mechanisms including the Natural Killer Group 2 member D (NKG2D) receptor-ligand system play an important role in tumor immune surveillance and targeting the NKG2D system might be beneficial. However, before considering any kind of immunotherapy, a precise characterization of the immune system is important, particularly in GBM patients where conventional therapies with impact on the immune system are frequently co-administered. Here we performed an in-depth immunophenotyping of GBM patients and age-matched healthy controls and analyzed NKG2D ligand expression on primary GBM cells ex vivo. We report that GBM patients have a compromised innate immune system irrespective of steroid (dexamethasone) medication. However, dexamethasone drastically reduced the number of immune cells in the blood of GBM patients. Moreover, higher counts of immune cells influenced by dexamethasone like CD45⁺ lymphocytes and non-Vδ2 γδ T cells were associated with better overall survival. Higher levels of NKG2D ligands on primary GBM tumor cells were observed in patients who received radiochemotherapy, pointing towards increased immunogenic potential of GBM cells following standard radiochemotherapy. This study sheds light on how steroids and radiochemotherapy affect immune cell parameters of GBM patients, a pre-requisite for the development of new therapeutic strategies targeting the immune system in these patients.

The Sequence of Delta24-RGD and TMZ Administration in Malignant Glioma Affects the Role of CD8+T Cell Anti-tumor Activity

The conditionally replicating oncolytic adenovirus Delta24-RGD (Ad) is currently under investigation in clinical trials for glioblastoma, including in combination with temozolomide (TMZ), the standard chemotherapy for this tumor. Previously, we showed that the efficacy of Delta24-RGD in a murine model is primarily dependent on the virus-induced anti-tumor immune response. As observed with most chemotherapies, TMZ has pronounced immune-modulating effects. Here, we studied the combined effects of these treatments in a murine glioma model. In vitro, we observed a synergistic activity between Delta24-RGD and TMZ. In vivo, C57BL/6 mice bearing intracranial GL261 tumors were treated with TMZ for 5 days either prior to intratumoral Delta24-RGD injection (TMZ/Ad) or post virus injection (Ad/TMZ). Notably, the Ad/TMZ regimen led to similar tumoral CD8⁺ T cell influx as the virus-only treatment, but increased the ability of CD8⁺ T cells to specifically recognize the tumor cells. This was accompanied by improved survival. The TMZ/Ad regimen also improved survival significantly compared to controls, but not compared to virus alone. In this group, the influx of dendritic cells is impaired, followed by a significantly lower number of tumor-infiltrating CD8⁺ T cells and no recognition of tumor cells. Depletion of either CD4⁺ T cells or CD8⁺ T cells impaired the efficacy of Delta24-RGD, underscoring the role of these cells in therapeutic activity of the virus. Overall, we show that the addition of TMZ to Delta24-RGD treatment leads to a significant increase in survival and that the order of sequence of these treatments affects the CD8⁺T cell anti-tumor activity.

Cutaneous invasive aspergillosis in a patient with glioblastoma receiving long-term temozolomide and corticosteroid therapy

Glioblastoma is an aggressive brain tumor that requires multidisciplinary treatment including adjuvant radiotherapy, chemotherapy, and adjunct corticosteroids. Temozolomide is a commonly used chemotherapy drug and frequently causes lymphocytopenia. We describe the case of a 67-year-old woman with cutaneous invasive aspergillosis who had received long-term temozolomide and corticosteroid therapy for glioblastoma. She presented with multiple indurations, erythema, and purpura, some of which produced purulent discharge, in the anterior abdomen. Extensive intra- or inter-muscular abscesses of the right anterior abdominal wall were also observed. Her absolute lymphocyte counts were 156/μL on admission. Cultures obtained from the wound yielded Aspergillus fumigatus. She was diagnosed with secondary cutaneous invasive aspergillosis, which likely resulted from hematogenous dissemination. Although rare, this case illustrates that temozolomide-induced lymphocytopenia, especially in cases of concomitant corticosteroid use, can be associated with severe invasive aspergillosis.

The Spectrum of Serious Infections Among Patients Receiving Immune Checkpoint Blockade for the Treatment of Melanoma

The risk of infection among patients receiving immune checkpoint blockade is unknown. We retrospectively reviewed medical records of 740 patients with melanoma who received immune checkpoint blockers. Serious infection occurred in 54 patients (7.3%). The main risk factors were receipt of corticosteroids and/or infliximab.

Evaluation of surrogate tissues as indicators of drug activity in a melanoma skin model

The development of novel cancer treatments is a challenging task, partly because results from model systems often fail to predict drug efficacy in humans, and also tumors are often inaccessible for biochemical analysis, preventing effective monitoring of drug activity in vivo. Utilizing a model system, we evaluated the use of drug-induced DNA damage in surrogate tissues as indicators of drug efficacy. Samples of a commercially available melanoma skin model (Mattek MLNM-FT-A375) containing keratinocyte and fibroblast layers with melanoma nodules were subjected to various chemotherapeutic regimens for one, four, or eight days. At these times they were analyzed for DNA double-stranded breaks (γH2AX foci) and apoptosis (TUNEL). A wide range of drug responses in both tumor and normal tissues were observed and cataloged. For the melanoma, the most common drug response was apoptosis. The basal keratinocyte layer, which was the most reliable indicator of drug response in the melanoma skin model, responded with γH2AX foci formation that was abrupt and transient. The relationships between tumor and surrogate tissue drug responses are complex, indicating that while surrogate tissue drug responses may be useful clinical tools, careful control of variables such as the timing of sampling may be important in interpreting the results.

Synergistic antitumor effect with indoleamine 2,3-dioxygenase inhibition and temozolomide in a murine glioma model

OBJECT

Indoleamine 2,3-dioxygenase (IDO), a key enzyme of tryptophan (Trp) metabolism, is involved in tumor-derived immune suppression through depletion of Trp and accumulation of the metabolite kynurenine, resulting in inactivation of natural killer cells and generation of regulatory T cells (Tregs). It has been reported that high expression of IDO in cancer cells is associated with suppression of the antitumor immune response and is consistent with a poor prognosis. Thus, IDO may be a therapeutic target for malignant cancer. The authors have recently shown that IDO expression is markedly increased in human glioblastoma and secondary glioblastoma with malignant change, suggesting that IDO targeting may also have therapeutic potential for patients with glioma. The aim of this study was to investigate the antitumor effect of IDO inhibition and to examine the synergistic function of IDO inhibitor and temozolomide (TMZ) in a murine glioma model.

METHODS

Murine glioma GL261 cells and human glioma U87 cells were included in this study. The authors used 3 mouse models to study glioma cell growth: 1) a subcutaneous ectopic model, 2) a syngeneic intracranial orthotopic model, and 3) an allogenic intracranial orthotopic model. IDO inhibition was achieved via knockdown of IDO in GL261 cells using short hairpin RNA (shRNA) and through oral administration of the IDO inhibitor, 1-methyl-l-tryptophan (1-MT). Tumor volume in the subcutaneous model and survival time in the intracranial model were evaluated.

RESULTS

In the subcutaneous model, oral administration of 1-MT significantly suppressed tumor growth, and synergistic antitumor effects of 1-MT and TMZ were observed (p < 0.01). Mice containing intracranially inoculated IDO knockdown cells had a significantly longer survival period as compared with control mice (p < 0.01).

CONCLUSIONS

These results suggest that IDO expression is implicated in immunosuppression and tumor progression in glioma cells. Therefore, combining IDO inhibition with standard TMZ treatment could be an encouraging therapeutic strategy for patients with malignant glioma.

Malignant gliomas: old and new systemic treatment approaches

Background

Malignant (high-grade) gliomas are rapidly progressive brain tumours with very high morbidity and mortality. Until recently, treatment options for patients with malignant gliomas were limited and mainly the same for all subtypes of malignant gliomas. The treatment included surgery and radiotherapy. Chemotherapy used as an adjuvant treatment or at recurrence had a marginal role.

Conclusions

Nowadays, the treatment of malignant gliomas requires a multidisciplinary approach. The treatment includes surgery, radiotherapy and chemotherapy. The chosen approach is more complex and individually adjusted. By that, the effect on the survival and quality of life is notable higher.

Neoadjuvant therapy for melanoma: a promising therapeutic approach and an ideal platform in drug development

Patients with locoregionally advanced but surgically operable melanoma continue to carry a high risk of relapse and death despite the best available standard management approaches. Neoadjuvant studies targeting this patient population tested chemotherapy with temozolomide and biochemotherapy (BCT), in which BCT demonstrated high tumor response rates but was eventually abandoned with the failure of BCT to deliver survival benefits in randomized trials of metastatic disease. Smaller neoadjuvant immunotherapy studies with interferon (IFN) alfa and ipilimumab have yielded promising clinical activity and important mechanistic insights and biomarker findings. Newer targeted and immunotherapeutic agents and combinations currently are being translated into the neoadjuvant setting at an accelerated pace and carry significant clinical promise. In drug development, the neoadjuvant approach allows access to blood and tumor tissue before and after initiation of systemic therapy, which allows for the conduct of novel mechanistic and biomarker studies in the circulation and the tumor microenvironment. Such studies may guide drug development and allow for the discovery of predictive biomarkers selected on the basis of their capacity to classify patients according to the degree of benefit from treatment or the risk for significant toxicity.

Serum elevation of B lymphocyte stimulator does not increase regulatory B cells in glioblastoma patients undergoing immunotherapy

Regulatory B cells that secrete IL-10 (IL-10(+) Bregs) represent a suppressive subset of the B cell compartment with prominent anti-inflammatory capacity, capable of suppressing cellular and humoral responses to cancer and vaccines. B lymphocyte stimulator (BLyS) is a key regulatory molecule in IL-10(+) Breg biology with tightly controlled serum levels. However, BLyS levels can be drastically altered upon chemotherapeutic intervention. We have previously shown that serum BLyS levels are elevated, and directly associated, with increased antigen-specific antibody titers in patients with glioblastoma (GBM) undergoing lymphodepletive temozolomide chemotherapy and vaccination. In this study, we examined corresponding IL-10(+) Breg responses within this patient population and demonstrate that the IL-10(+) Breg compartment remains constant before and after administration of the vaccine, despite elevated BLyS levels in circulation. IL-10(+) Breg frequencies were not associated with serum BLyS levels, and ex vivo stimulation with a physiologically relevant concentration of BLyS did not increase IL-10(+) Breg frequency. However, BLyS stimulation did increase the frequency of the overall B cell compartment and promoted B cell proliferation upon B cell receptor engagement. Therefore, using BLyS as an adjuvant with therapeutic peptide vaccination could promote humoral immunity with no increase in immunosuppressive IL-10(+) Bregs. These results have implications for modulating humoral responses in human peptide vaccine trials in patients with GBM.

Immune Checkpoint Modulators: An Emerging Antiglioma Armamentarium

Immune checkpoints have come to the forefront of cancer therapies as a powerful and promising strategy to stimulate antitumor T cell activity. Results from recent preclinical and clinical studies demonstrate how checkpoint inhibition can be utilized to prevent tumor immune evasion and both local and systemic immune suppression. This review encompasses the key immune checkpoints that have been found to play a role in tumorigenesis and, more specifically, gliomagenesis. The review will provide an overview of the existing preclinical and clinical data, antitumor efficacy, and clinical applications for each checkpoint with respect to GBM, as well as a summary of combination therapies with chemotherapy and radiation.

Complications from pharmacotherapy

The pharmacotherapy management of cancers of the nervous system has significant overlap with systemic solid cancers that may utilize similar drugs or agents. There is however a unique aspect related to central nervous system (CNS) cancers where therapies directed against a malignant process may have enhanced toxicities or toxicities unique to the CNS. In addition, many agents used to treat CNS malignancies have unique CNS toxicities that may require a specific intervention. This chapter attempts to review conventional and biologic therapies utilized for CNS malignancies and characterize expected and, if known, unique toxicities.

Antitumor activity of a polypyridyl chelating ligand: in vitro and in vivo inhibition of glioma

Glioblastoma multiforme is an extremely aggressive and invasive form of central nervous system tumor commonly treated with the chemotherapeutic drug Temozolomide. Unfortunately, even with treatment, the median survival time is less than 12 months. 2,9-Di-sec-butyl-1,10-phenanthroline (SBP), a phenanthroline-based ligand originally developed to deliver gold-based anticancer drugs, has recently been shown to have significant antitumor activity in its own right. SBP is hypothesized to initiate tumor cell death via interaction with non-DNA targets, and considering most glioblastoma drugs kill tumors through DNA damage processes, SBP was tested as a potential novel drug candidate against glial-based tumors. In vitro studies demonstrated that SBP significantly inhibited the growth of rodent GL-26 and C6 glioma cells, as well as human U-87, and SW1088 glioblastomas/astrocytomas. Furthermore, using a syngeneic glioma model in mice, in vivo administration of SBP significantly reduced tumor volume and increased survival time. There was no significant toxicity toward nontumorigenic primary murine and human astrocytes in vitro, and limited toxicity was observed in ex vivo tissues obtained from noncancerous mice. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining and recovery assays suggest that SBP induces apoptosis in gliomas. This exploratory study suggests SBP is effective in slowing the growth of tumorigenic cells in the brain while exhibiting limited toxicity to normal cells and tissues and should therefore be further investigated for its potential in glioblastoma treatment.

Pre-radiation lymphocyte harvesting and post-radiation reinfusion in patients with newly diagnosed high grade gliomas

Radiation (RT), temozolomide (TMZ), and dexamethasone in newly diagnosed high grade gliomas (HGG) produces severe treatment-related lymphopenia (TRL) that is associated with early cancer-related deaths. This TRL may result from inadvertent radiation to circulating lymphocytes. This study reinfused lymphocytes, harvested before chemo-radiation, and assessed safety, feasibility, and trends in lymphocyte counts. Patients with newly diagnosed HGG and total lymphocyte counts (TLC) ≥ 1000 cells/mm(3) underwent apheresis. Cryopreserved autologous lymphocytes were reinfused once radiation was completed. Safety, feasibility, and trends in TLC, T cell subsets and cytokines were studied. Serial TLC were also compared with an unreinfused matched control group. Ten patients were harvested (median values: age 56 years, dexamethasone 3 mg/day, TLC/CD4 1980/772 cells/mm(3)). After 6 weeks of RT/TMZ, TLC fell 69 % (p < 0.0001) with similar reductions in CD4, CD8 and NK cells but not Tregs. Eight patients received lymphocyte reinfusions (median = 7.0 × 10(7) lymphocytes/kg) without adverse events. A post-reinfusion TLC rise of ≥300 cells/mm(3) was noted in 3/8 patients at 4 weeks and 7/8 at 14 weeks which was similar to 23 matched controls. The reduced CD4/CD8 ratio was not restored by lymphocyte reinfusion. Severe lymphopenia was not accompanied by elevated serum interleukin-7 (IL-7) levels. This study confirms that severe TRL is common in HGG and is not associated with high plasma IL-7 levels. Although lymphocyte harvesting/reinfusion is feasible and safe, serial lymphocyte counts are similar to unreinfused matched controls. Studies administering higher lymphocyte doses and/or IL-7 should be considered to restore severe treatment-related lymphopenia in HGG.

Wilms tumor 1 peptide vaccination combined with temozolomide against newly diagnosed glioblastoma: safety and impact on immunological response

To investigate the safety of combined Wilms tumor 1 peptide vaccination and temozolomide treatment of glioblastoma, a phase I clinical trial was designed. Seven patients with histological diagnosis of glioblastoma underwent concurrent radiotherapy and temozolomide therapy. Patients first received Wilms tumor 1 peptide vaccination 1 week after the end of combined concurrent radio/temozolomide therapy, and administration was continued once per week for 7 weeks. Temozolomide maintenance was started and performed for up to 24 cycles, and the observation period for safety encompassed 6 weeks from the first administration of maintenance temozolomide. All patients showed good tolerability during the observation period. Skin disorders, such as grade 1/2 injection-site reactions, were observed in all seven patients. Although grade 3 lymphocytopenia potentially due to concurrent radio/temozolomide therapy was observed in five patients (71.4 %), no other grade 3/4 hematological or neurological toxicities were observed. No autoimmune reactions were observed. All patients are still alive, and six are on Wilms tumor 1 peptide vaccination without progression, yielding a progression-free survival from histological diagnosis of 5.2-49.1 months. Wilms tumor 1 peptide vaccination was stopped in one patient after 12 injections by the patient's request. The safety profile of the combined Wilms tumor 1 peptide vaccination and temozolomide therapy approach for treating glioblastoma was confirmed.

Medical management of brain tumors and the sequelae of treatment

Patients with malignant brain tumors are prone to complications that negatively impact their quality of life and sometimes their overall survival as well. Tumors may directly provoke seizures, hypercoagulable states with resultant venous thromboembolism, and mood and cognitive disorders. Antitumor treatments and supportive therapies also produce side effects. In this review, we discuss major aspects of supportive care for patients with malignant brain tumors, with particular attention to management of seizures, venous thromboembolism, corticosteroids and their complications, chemotherapy including bevacizumab, and fatigue, mood, and cognitive dysfunction.

Severity, etiology and possible consequences of treatment-related lymphopenia in patients with newly diagnosed high-grade gliomas

Lymphopenia is a common consequence of therapy for malignant glioma. Current standard therapy includes corticosteroids, temozolomide and radiation therapy, all of which are toxic to lymphocytes. The resulting immunosuppression has serious clinical consequences. Decreased lymphocyte counts can result in opportunistic infections, decreased efficacy of immunotherapy and reduced overall survival. The exact mechanisms underlying the association between decreased survival and lymphopenia in malignant glioma patients are unclear. However, as lymphocytes are key effector cells in the immune response to cancer, it is likely that depleting their numbers renders the immune system less effective at eliminating malignant cells. Currently, no strategies exist for the prevention or reversal of treatment-related immunosuppression in malignant glioma patients, although there are several promising theoretical approaches. This article reviews the current state of knowledge regarding the severity, etiology and possible consequences of treatment-related lymphopenia in patients with malignant glioma.

Generation of CAR T cells for adoptive therapy in the context of glioblastoma standard of care

Adoptive T cell immunotherapy offers a promising strategy for specifically targeting and eliminating malignant gliomas. T cells can be engineered ex vivo to express chimeric antigen receptors specific for glioma antigens (CAR T cells). The expansion and function of adoptively transferred CAR T cells can be potentiated by the lymphodepletive and tumoricidal effects of standard of care chemotherapy and radiotherapy. We describe a method for generating CAR T cells targeting EGFRvIII, a glioma-specific antigen, and evaluating their efficacy when combined with a murine model of glioblastoma standard of care. T cells are engineered by transduction with a retroviral vector containing the anti-EGFRvIII CAR gene. Tumor-bearing animals are subjected to host conditioning by a course of temozolomide and whole brain irradiation at dose regimens designed to model clinical standard of care. CAR T cells are then delivered intravenously to primed hosts. This method can be used to evaluate the antitumor efficacy of CAR T cells in the context of standard of care.

Discovery of mitochondria-targeting berberine derivatives as the inhibitors of proliferation, invasion and migration against rat C6 and human U87 glioma cells

This research aims to synthesize lipophilic berberine derivatives and evaluate their antiglioma effects on C6 and U87 cells.

Haematological toxicity of Valproic acid compared to Levetiracetam in patients with glioblastoma multiforme undergoing concomitant radio-chemotherapy: a retrospective cohort study

Patients with glioblastoma multiforme (GBM) and symptomatic seizures are in need of a sufficient antiepileptic treatment. Haematological toxicity is a limiting side effect of both, first line radio-chemotherapy with temozolomide (TMZ) and co-medication with antiepileptic drugs. Valproic acid (VPA) and levetiracetam (LEV) are considered favourable agents in brain tumor patients with seizures, but are commonly reported to induce haematological side effects on their own. We hypothesized, that antiepileptic treatment with these agents has no increased impact on haematological side effects during radio-chemotherapy in the first line setting. We included 104 patients from two neuro-oncologic centres with GBM and standard radio-chemotherapy in a retrospective cohort study. Patients were divided according to their antiepileptic treatment with either VPA, LEV or without antiepileptic drug therapy (control group). Declines in haemoglobin levels and absolute blood cell counts for neutrophil granulocytes, lymphocytes and thrombocytes were analyzed twice during concomitant and once during adjuvant phase. A comparison between the examined groups was performed, using a linear mixed model. Neutrophil granulocytes, lymphocytes and thrombocytes significantly decreased over time in all three groups (all p < 0.012), but there was no significant difference between the compared groups. A significant decline in haemoglobin was observed in the LEV treated group (p = 0.044), but did not differ between the compared groups. As a novel finding, this study demonstrates that co-medication either with VPA or LEV in GBM patients undergoing first line radio-chemotherapy with TMZ has no additional impact on medium-term haematological toxicity.

Depletion of T lymphocytes is correlated with response to temozolomide in melanoma patients

Therapeutic strategies to deplete lymphocytes, especially regulatory T cells, in cancer patients have been proposed to increase the benefits of (immuno)chemotherapy. In this study, we explored the influence of temozolomide (TMZ) on different T-cell populations and addressed if the depletion of CD4⁺ T cells would be associated to the clinical benefits of TMZ. Patients were treated with TMZ (150 mg/m² daily, every two weeks on a four-week schedule) until disease progression. Changes in T-lymphocyte subsets were characterized by flow cytometry. All patients enrolled in this study had histologically verified unresectable stage IV melanoma. Objective responses were induced in 12.5% of the patients, while 42.5% of them obtained short-term disease stabilization. The median progression-free survival (PFS) of this patient cohort was 8.7 mo. Lymphopenia (< 0.7 × 10⁹ cells/L, grade 2) developed in 71% of the patients after 3 treatment cycles (~100 d). The development of grade 2 lymphopenia after the 3rd cycle of therapy positively correlated with clinical outcome (p = 0.01), and was linked, though non-significantly, to prolonged median PFS (303 vs. 200 d). In addition, significant changes in CD8⁺ T-cell subgroups were observed, notably a shift from naïve T cells toward more differentiated memory T cells. Finally, we demonstrated that specific CD8⁺ T-cell responses against selected tumor associated antigens (TAAs) were enhanced by the administration of TMZ (p = 0.04), while virus-specific T-cell responses were stable. Thus, immunological monitoring in the course of TMZ treatment might become an important tool for clinical guidance in the future.

Enhancing dendritic cell-based vaccination for highly aggressive glioblastoma

INTRODUCTION

Patients with primary glioblastoma (GBM) have a dismal prognosis despite standard therapy, which can induce potentially deleterious side effects. Arming the immune system is an alternative therapeutic approach, as its cellular effectors and inherent capacity for memory can be utilized to specifically target invasive tumor cells, while sparing collateral damage to otherwise healthy brain parenchyma.

AREAS COVERED

Active immunotherapy is aimed at eliciting a specific immune response against tumor antigens. Dendritic cells (DCs) are one of the most potent activators of de novo and recall immune responses and are thus a vehicle for successful immunotherapy. Currently, investigators are optimizing DC vaccines by enhancing maturation status and migratory potential to induce more potent antitumor responses. An update on the most recent DC immunotherapy trials is provided.

EXPERT OPINION

Targeting of unique antigens restricted to the tumor itself is the most important parameter in advancing DC vaccines. In order to overcome intrinsic mechanisms of immune evasion observed in GBM, the future of DC-based therapy lies in a multi-antigenic vaccine approach. Successful targeting of multiple antigens will require a comprehensive understanding of all immunologically relevant oncological epitopes present in each tumor, thereby permitting a rational vaccine design.

Chemotherapy in the management of advanced cutaneous malignant melanoma

The recent past has witnessed unprecedented clinical progress in the treatment of advanced malignant melanoma through targeting of mutant BRAF in approximately 50% of patients and immune check point blockade in all patients. As has been well documented, responses to targeted therapy are of limited duration, and rates of clinical benefit to immunotherapy are modest. Given these factors, palliation of patients with chemotherapy remains an essential aspect of melanoma oncology. Many chemotherapeutics (and combinations with other agents, such as immunotherapy) have been evaluated in melanoma, although no chemotherapy regimen has been documented to provide an overall survival benefit in a prospective, randomized, well-controlled phase III study. We provide an overview of the development of the most common chemotherapy regimens for melanoma, discuss the clinical trial evidence supporting and contrasting them, and highlight appropriate clinical situations in which they might be used. We also discuss the future of chemotherapy for melanoma, noting the potential for combinations of chemotherapy with either targeted or immunotherapeutic agents.

Intratumoral temozolomide synergizes with immunotherapy in a T cell-dependent fashion

Despite temozolomide (TMZ) treatment, the prognosis for patients with glioblastoma multiforme is still dismal. As dose escalation of TMZ is limited by systemic toxicity, intratumoral delivery emerges as an attractive treatment modality, which may sustain cytotoxic drug concentrations intratumorally and induce immunogenic cell death. Both clinical and experimental gliomas have responded to immunotherapy, but the benefit of simultaneous chemo- and immunotherapy is inadequately studied. Here, we monitored survival of GL261-bearing C57BL/6 mice following a 3-day treatment with either intratumoral TMZ (micro-osmotic pump, 4.2 mg/kg/day) or systemic TMZ (i.p. injections, 50 mg/kg/day) alone, or combined with immunization using GM-CSF secreting GL261 cells. Peripheral and intratumoral leukocytes were analyzed by flow cytometry and immunohistochemistry. Intratumoral TMZ induced higher survival rate than systemic TMZ (45 vs. 8%). When T cells were depleted following intratumoral TMZ, the therapeutic effect was completely abrogated (0 % survival). Intratumoral TMZ synergistically increased survival rate of immunized mice (from 25 to 83%), while systemic TMZ failed (0%). While systemic TMZ induced a transient leukopenia, intratumoral TMZ and immunotherapy sustained the proliferation of CD8+ T cells and decreased the number of intratumoral immunosuppressive cells. In conclusion, intratumoral TMZ alone or in combination with immunotherapy could cure glioma-bearing mice, due to attenuation of local immunosuppression and increase in potential effector immune cells.

Toca 511 gene transfer and 5-fluorocytosine in combination with temozolomide demonstrates synergistic therapeutic efficacy in a temozolomide-sensitive glioblastoma model

Toca 511 (vocimagene amiretrorepvec), an amphotropic retroviral replicating vector (RRV), can successfully and safely deliver a functional, optimized cytosine deaminase (CD) gene to tumors in orthotopic glioma models. This agent, in conjunction with subsequent oral extended-release 5-fluorocytosine (5-FC) (Toca FC), is currently under investigation in patients with recurrent high-grade glioma . Temozolomide (TMZ) with radiation is the most frequently used first-line treatment for patients with glioblastoma, the most common and aggressive form of primary brain cancer in adults. However, subsets of patients with certain genetic alterations do not respond well to TMZ treatment and the overall median survival for patients who respond remains modest, suggesting that combinatorial approaches may be necessary to significantly improve outcomes. We show that in vitro TMZ delays but does not prevent RRV spread, nor interfere with Toca 511+5-FC-mediated cell killing in glioma tumor cells, and in vivo there is no significant hematologic effect from the combination of 5-FC and the clinically relevant dose of TMZ. A synergistic long-term survival advantage is observed in mice bearing an orthotopic TMZ-sensitive glioma after Toca 511 administration followed by coadministration of TMZ and 5-FC. These results provide support for the investigation of this novel combination treatment strategy in patients with newly diagnosed malignant glioma.

Aspergillosis in a patient receiving temozolomide for the treatment of glioblastoma

Leukopenia and selective CD4+ lymphopenia represent major adverse events associated with the use of temozolomide (TMZ), an oral alkylating agent incorporated in the treatment of glioblastoma (GBM). The increased risk of opportunistic infections, including those caused by Pneumocystis jiroveci and cytomegalovirus, has been previously described in the literature. Here we report the case, the first to our knowledge, of a patient with pulmonary invasive aspergillosis immediately after the completion of chemoradiation with TMZ for GBM. Diagnosis was confirmed through a CT-guided lung biopsy, and the patient had excellent response to systemic voriconazole. This case illustrates that TMZ can be associated with severe opportunistic infections, presumably associated with T lymphocyte immune dysfunction, and patients exposed to this agent should be carefully monitored.

The role of MGMT testing in clinical practice: a report of the association for molecular pathology

Recent advances in modern molecular technologies allow for the examination and measurement of cancer-related genomic changes. The number of molecular tests for evaluation of diagnostic, prognostic, or predictive markers is expected to increase. In recent years, O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation has been firmly established as a biomarker in patients diagnosed with gliomas, for both clinical trials and routine clinical management. Similarly, molecular markers, such as loss of heterozygosity (LOH) for 1p/19q have already demonstrated clinical utility in treatment of oligodendroglial tumors, and others might soon show clinical utility. Furthermore, nonrandom associations are being discovered among MGMT, 1p/19q LOH, isocitrate dehydrogenase (IDH) mutations, and other tumor-specific modifications that could possibly enhance our ability to predict outcome and response to therapy. While pathologists are facing new and more complicated requests for clinical genomic testing, clinicians are challenged with increasing numbers of molecular data coming from molecular pathology and genomic medicine. Both pathologists and oncologists need to understand the clinical utility of molecular tests and test results, including issues of turnaround time, and their impact on the application of targeted treatment regimens. This review summarizes the existing data that support the rationale for MGMT promoter methylation testing and possibly other molecular testing in clinically defined glioma subtypes. Various molecular testing platforms for evaluation of MGMT methylation status are also discussed.

Temozolomide-related hematologic toxicity

Temozolomide (TMZ) is an oral alkylating agent used for the treatment of recurrent or newly diagnosed malignant gliomas with significant survival benefit. TMZ is generally well tolerated and safe. The most common side effects are mild to moderate, and are represented by fatigue, nausea, vomiting, thrombocytopenia, and neutropenia. However severe hematologic adverse events (HAEs), including myelodysplastic syndrome and aplastic anemia, have also been reported. In this review we present an overview of the available literature of HAEs after exposure to TMZ.

Low-dose temozolomide before dendritic-cell vaccination reduces (specifically) CD4+CD25++Foxp3+ regulatory T-cells in advanced melanoma patients

BACKGROUND

In cancer immunotherapy, dendritic cells (DCs) play a fundamental role in the dialog between innate and adaptive immune response, but several immunosuppressive mechanisms remain to be overcome. For example, a high number of CD4+CD25++Foxp3+ regulatory T-cells (Foxp3+Tregs) have been observed in the peripheral blood and tumor microenvironment of cancer patients. On the basis of this, we conducted a study on DC-based vaccination in advanced melanoma, adding low-dose temozolomide to obtain lymphodepletion.

METHODS

Twenty-one patients were entered onto our vaccination protocol using autologous DCs pulsed with autologous tumor lysate and keyhole limpet hemocyanin. Patients received low-dose temozolomide before vaccination and 5 days of low-dose interleukin-2 (IL-2) after vaccination. Circulating Foxp3+Tregs were evaluated before and after temozolomide, and after IL-2.

RESULTS

Among the 17 evaluable patients we observed 1 partial response (PR), 6 stable disease (SD) and 10 progressive disease (PD). The disease control rate (PR+SD = DCR) was 41% and median overall survival was 10 months. Temozolomide reduced circulating Foxp3+Treg cells in all patients. A statistically significant reduction of 60% was observed in Foxp3+Tregs after the first cycle, whereas the absolute lymphocyte count decreased by only 14%. Conversely, IL-2 increased Foxp3+Treg cell count by 75.4%. Of note the effect of this cytokine, albeit not statistically significant, on the DCR subgroup led to a further 33.8% reduction in Foxp3+Treg cells.

CONCLUSIONS

Our results suggest that the combined immunological therapy, at least as far as the DCR subgroup is concerned, effectively reduced the number of Foxp3+Treg cells, which exerted a blunting effect on the growth-stimulating effect of IL-2. However, this regimen, with its current modality, would not seem to be capable of improving clinical outcome.

Targeting Tregs in Malignant Brain Cancer: Overcoming IDO

One of the hallmark features of glioblastoma multiforme (GBM), the most common adult primary brain tumor with a very dismal prognosis, is the accumulation of CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs). Regulatory T cells (Tregs) segregate into two primary categories: thymus-derived natural Tregs (nTregs) that develop from the interaction between immature T cells and thymic epithelial stromal cells, and inducible Tregs (iTregs) that arise from the conversion of CD4⁺FoxP3⁻ T cells into FoxP3 expressing cells. Normally, these Treg subsets complement one another’s actions by maintaining tolerance of self-antigens, thereby suppressing autoimmunity, while also enabling effective immune responses toward non-self-antigens, thus promoting infectious protection. However, Tregs have also been shown to be associated with the promotion of pathological outcomes, including cancer. In the setting of GBM, nTregs appear to be primary players that contribute to immunotherapeutic failure, ultimately leading to tumor progression. Several attempts have been made to therapeutically target these cells with variable levels of success. The blood brain barrier-crossing chemotherapeutics, temozolomide, and cyclophosphamide (CTX), vaccination against the Treg transcriptional regulator, FoxP3, as well as mAbs against Treg-associated cell surface molecules CD25, CTLA-4, and GITR are all different therapeutic approaches under investigation. Contributing to the poor success of past approaches is the expression of indoleamine 2,3-dioxygenase 1 (IDO), a tryptophan catabolizing enzyme overexpressed in GBM, and critically involved in regulating tumor-infiltrating Treg levels. Herein, we review the current literature on Tregs in brain cancer, providing a detailed phenotype, causative mechanisms involved in their pathogenesis, and strategies that have been used to target this population, therapeutically.

Decision making and management of gliomas: practical considerations

Over the last decade, diagnostic options and introduction of novel treatments have expanded the armamentarium in the management of malignant glioma. Combined chemoradiotherapy has become the standard of care in glioblastoma up to the age of 70 years, while treatment in elderly patients or with lower grade glioma is less well defined. Molecular markers define different disease subtypes and allow for adapted treatment selection. This review focuses on simple questions arising in the daily management of patients.

Myeloablative temozolomide enhances CD8⁺ T-cell responses to vaccine and is required for efficacy against brain tumors in mice

Temozolomide (TMZ) is an alkylating agent shown to prolong survival in patients with high grade glioma and is routinely used to treat melanoma brain metastases. A prominent side effect of TMZ is induction of profound lymphopenia, which some suggest may be incompatible with immunotherapy. Conversely, it has been proposed that recovery from chemotherapy-induced lymphopenia may actually be exploited to potentiate T-cell responses. Here, we report the first demonstration of TMZ as an immune host-conditioning regimen in an experimental model of brain tumor and examine its impact on antitumor efficacy of a well-characterized peptide vaccine. Our results show that high-dose, myeloablative (MA) TMZ resulted in markedly reduced CD4(+), CD8(+) T-cell and CD4(+)Foxp3(+) TReg counts. Adoptive transfer of naïve CD8(+) T cells and vaccination in this setting led to an approximately 70-fold expansion of antigen-specific CD8(+) T cells over controls. Ex vivo analysis of effector functions revealed significantly enhanced levels of pro-inflammatory cytokine secretion from mice receiving MA TMZ when compared to those treated with a lower lymphodepletive, non-myeloablative (NMA) dose. Importantly, MA TMZ, but not NMA TMZ was uniquely associated with an elevation of endogenous IL-2 serum levels, which we also show was required for optimal T-cell expansion. Accordingly, in a murine model of established intracerebral tumor, vaccination-induced immunity in the setting of MA TMZ-but not lymphodepletive, NMA TMZ-led to significantly prolonged survival. Overall, these results may be used to leverage the side-effects of a clinically-approved chemotherapy and should be considered in future study design of immune-based treatments for brain tumors.

Temozolomide-related idiosyncratic and other uncommon toxicities: a systematic review

Temozolomide (TMZ)-related idiosyncratic and other uncommon toxicities have been reported. To better characterize these toxicities and to identify any associated risk factors, we performed a systematic review. We searched the PubMed database, limited to the English language, published between 1999 and December 2011. We selected only those articles in which TMZ was temporally related and was the sole or main contributing chemotherapeutic drug to idiosyncratic drug reactions (IDRs) and other uncommon toxicities. Hematological IDRs are biopsy-proven aplastic anemia or grade V toxicity or grade IV toxicity with slow and incomplete hematological recovery. Seventy-three cases were identified, including 21 hematological IDRs, 31 nonhematological IDRs and uncommon infections, and 21 second primary cancers. With a caveat of publication and reporting bias, the following observations could be made. The hematological IDRs predominantly occurred in female patients (exact binomial two-tailed, P=0.0041) and most patients were receiving TMZ concomitantly with radiotherapy for glioma. The median duration of exposure to TMZ was 30 days and the median cumulative TMZ exposure was 2250 mg/m (range, 500-6900 mg/m). The sex predilection was not evident in nonhematological IDRs and other uncommon toxicities. TMZ-induced pneumonitis and cholestatic hepatitis are emerging as a nonhematological hypersensitive reaction and IDR, respectively. For TMZ-related myelodysplasia or leukemia, the cumulative dose of TMZ ranged from 1400 to 30 000 mg/m. The cumulative dose of TMZ was lower and latency was shorter with a previous exposure to other leukemogenic drugs, suggesting that TMZ may have augmented the leukemogenic potential of other drugs. Early appearance of profound myelosuppression during the course of TMZ and concurrent radiotherapy could be a hematological IDR, which warrants prompt investigations to exclude aplastic anemia. Myelodysplasia or leukemia developed after a median TMZ exposure of 15 g/m.

Impact of temozolomide on immune response during malignant glioma chemotherapy

Malignant glioma, or glioblastoma, is the most common and lethal form of brain tumor with a median survival time of 15 months. The established therapeutic regimen includes a tripartite therapy of surgical resection followed by radiation and temozolomide (TMZ) chemotherapy, concurrently with radiation and then as an adjuvant. TMZ, a DNA alkylating agent, is the most successful antiglioma drug and has added several months to the life expectancy of malignant glioma patients. However, TMZ is also responsible for inducing lymphopenia and myelosuppression in malignant glioma patients undergoing chemotherapy. Although TMZ-induced lymphopenia has been attributed to facilitate antitumor vaccination studies by inducing passive immune response, in general lymphopenic conditions have been associated with poor immune surveillance leading to opportunistic infections in glioma patients, as well as disrupting active antiglioma immune response by depleting both T and NK cells. Deletion of O6-methylguanine-DNA-methyltransferase (MGMT) activity, a DNA repair enzyme, by temozolomide has been determined to be the cause of lymphopenia. Drug-resistant mutation of the MGMT protein has been shown to render chemoprotection against TMZ. The immune modulating role of TMZ during glioma chemotherapy and possible mechanisms to establish a strong TMZ-resistant immune response have been discussed.

Helping patients make the best decision regarding duration of temozolomide chemotherapy treatment

Outcomes for patients with glioblastoma have improved with the addition of temozolomide (TMZ) chemotherapy to radiation therapy followed by adjuvant TMZ for up to 1 year. Patients often wish to continue chemotherapy after the standard 1-year course. Whether to continue or to stop TMZ is a complex and stressful decision for the patient and family, and the decision should be based on a discussion of the known risks and benefits of each choice.

The association between treatment-related lymphopenia and survival in newly diagnosed patients with resected adenocarcinoma of the pancreas

Fifty-three patients with resected pancreatic adenocarcinoma were studied to determine if adjuvant chemo-radiation causes severe lymphopenia and if this is associated with adverse outcomes. Total lymphocyte counts (TLC) were normal in 91% before adjuvant chemo-radiation. Two months later, TLC fell by 63% (p < .0001) with 45% of patients having TLC < 500 cells/mm(3). Median survival in patients with low TLC was 14 versus 20 months (p = .048). Multivariate analysis revealed a significant association between treatment related lymphopenia and survival (HR 2.2, p = .014). Adjuvant chemo-radiation induced lymphopenia is frequent, severe, and an independent predictor for survival in patients with resected pancreatic adenocarcinoma.

Temozolomide and other potential agents for the treatment of glioblastoma multiforme

This article provides historical and recent perspectives related to the use of temozolomide for the treatment of glioblastoma multiforme. Temozolomide has quickly become part of the standard of care for the modern treatment of stage IV glioblastoma multiforme since its approval in 2005. Yet despite its improvements from previous therapies, median survival remains approximately 15 months, with a 2-year survival rate of 8% to 26%. The mechanism of action of this chemotherapeutic agent, conferred advantages and limitations, treatment resistance and rescue, and potential targets of future research are discussed.

Temozolomide in the management of dopamine agonist-resistant prolactinomas

BACKGROUND

The majority of prolactinomas respond to dopamine agonist therapy, but a proportion are resistant, requiring other treatments including surgery and/or radiotherapy. Temozolomide is an oral chemotherapy agent, which has been used as a salvage therapy to treat aggressive pituitary adenomas and carcinomas, including prolactinomas, unresponsive to all conventional treatment.

CASE SERIES

We report three patients where temozolomide was used in the treatment of refractory prolactinomas. Case 1 describes a patient with a highly invasive prolactinoma, resistant to all conventional therapy, which responded dramatically to temozolomide used as a salvage treatment. In case 2, temozolomide was used after incomplete surgical resection to relieve chiasmal compression and avoid chiasm exposure to radiotherapy. In case 3, temozolomide enabled radiotherapy to be deferred in a 16-year old with a resistant prolactinoma. In all three cases, the tumours were negative by immunostaining for methylguanine methyltransferase (MGMT).

LITERATURE REVIEW AND DISCUSSION

A review of the published literature reveals 51 reported cases of temozolomide treatment for pituitary tumours, including 20 prolactinomas. Fifteen of the 20 prolactinomas showed a good response to temozolomide. Our analysis demonstrates a strong association between MGMT-negative staining and a good response to temozolomide (OR 9.35, P = 0.0030). Current clinical practice is to use temozolomide as a salvage therapy after all conventional modalities of treatment have failed. We suggest that, in selected cases, consideration should be given to using temozolomide earlier in the treatment algorithm.

Dose dense 1 week on/1 week off temozolomide in recurrent glioma: a retrospective study

Alternative temozolomide regimens have been proposed to overcome O(6)-methylguanine-DNA methyltransferase mediated resistance. We investigated the efficacy and tolerability of 1 week on/1 week off temozolomide (ddTMZ) regimen in a cohort of patients treated with ddTMZ between 2005 and 2011 for the progression of a glioblastoma during or after chemo-radiation with temozolomide or a recurrence of another type of glioma after radiotherapy and at least one line of chemotherapy. Patients received ddTMZ at 100-150 mg/m(2)/d (days 1-7 and 15-21 in cycles of 28-days). All patients had a contrast enhancing lesion on MRI and the response was assessed by MRI using the RANO criteria; complete and partial responses were considered objective responses. Fifty-three patients were included. The median number of cycles of ddTMZ was 4 (range 1-12). Eight patients discontinued chemotherapy because of toxicity. Two of 24 patients with a progressive glioblastoma had an objective response; progression free survival at 6 months (PFS-6) in glioblastoma was 29%. Three of the 16 patients with a recurrent WHO grade 2 or 3 astrocytoma or oligodendroglioma or oligo-astrocytoma without combined 1p and 19q loss had an objective response and PFS-6 in these patients was 38%. Four out of the 12 evaluable patients with a recurrent WHO grade 2 or 3 oligodendroglioma or oligo-astrocytoma with combined 1p and 19q loss had an objective response; PFS-6 in these patients was 62%. This study indicates that ddTMZ is safe and effective in recurrent glioma, despite previous temozolomide and/or nitrosourea chemotherapy. Our data do not suggest superior efficacy of this schedule as compared to the standard day 1-5 every 4 weeks schedule.

Ex vivo functional analysis, expansion and adoptive transfer of cytomegalovirus-specific T-cells in patients with glioblastoma multiforme

The frequent detection of human cytomegalovirus (CMV) antigens in glioblastoma multiforme (GBM) has raised the possibility of exploiting CMV-specific T-cell immunotherapy to control this disease in CMV--seropositive patients. Here, we have conducted a comprehensive ex vivo profiling of CMV-specific CD8(+) T-cell responses in a cohort of GBM patients. Of the patients analyzed, approximately half exhibited serological evidence of past infection with CMV. Although no CMV-specific CD8(+) T-cell responses could be detected in the serologically negative GBM patients, virus-specific CD8(+) T-cell responses were detected in all seropositive GBM patients. Using major histocompatibility complex-peptide multimers, the frequency of CMV-specific T-cells in the patients detected ranged from 0.1 to 22% of CD8(+) T-cells and a high proportion of these cells were positive for the human natural killer-1 glycoprotein CD57. Furthermore, ex vivo polychromatic functional analysis of the CMV-specific T-cells from GBM patients revealed that large proportions of these cells were unable to produce multiple cytokines (macrophage inflammatory protein (MIP)-1β, tumor necrosis factor (TNF)α and interferon (IFN)γ) and displayed limited cytolytic function (CD107a mobilization) following stimulation with CMV peptide epitopes. However, in vitro stimulation with CMV peptide epitopes in the presence of γC cytokine dramatically reversed the polyfunctional profile of these antigen-specific T-cells with high levels of MIP-1β, TNFα, IFNγ and CD107a mobilization. Most importantly, adoptive transfer of these in vitro-expanded T-cells in combination with temozolomide (TMZ) therapy into a patient with recurrent GBM was coincident with a long-term disease-free survival. These studies provide an important platform for a formal assessment of combination therapies based on CMV-specific T-cells and TMZ for recurrent GBM.

Infections in neuro-oncology

Infections represent a serious and frequent complication in neuro-oncology patients. Decreased immune defences, along with poor nutritional status are the main predisposition factors. The combined therapeutic strategies of chemotherapy and radiotherapy may favour bone marrow depression and further increase the risk of developing opportunistic infections in brain tumour patients. The spectrum of infections in neuro-oncology patients is large and includes opportunistic infections by bacteria, viruses, fungi and parasites. Importantly, a high index of suspicion for opportunistic infections in general should be maintained, especially in glioma patients receiving dose-dense schedules of temozolomide. After neurosurgical procedures, infections most commonly present as meningitis, subdural empyema, or cerebral abscess. Infections represent a frequent and possibly serious complication in general immunocompromised oncology population. It should be underlined that infections are not limited to immunocompromised patients, being also present at the early disease stages, especially due to therapeutic strategies (chemo and radiotherapy, surgical procedures). Therefore this issue deserves more attention in neuroncology setting.

Invasive Mycoleptodiscus fungal cellulitis and myositis

We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with glioblastoma multiforme treated with temozolomide and corticosteroids. While the morphologic appearance of the isolate and its ability to grow at temperatures greater than 32°C were suggestive of Mycoleptodiscus indicus, some of the conidia were atypical for this species in that they had single septa and occasional lateral appendages. Furthermore, the isolate was different from M. indicus based on the sequencing analysis of two rDNA regions. This is the first case of Mycoleptodiscus invasive fungal disease in which the causative agent could not be resolved at the species level because of inconsistencies between morphological and molecular data.

Pneumocystis jirovecii pneumonia in non-HIV-infected patients: new risks and diagnostic tools

PURPOSE OF REVIEW

Non-HIV-infected populations are increasingly identified as being at risk for developing Pneumocystis jirovecii pneumonia (PJP). These patients typically present with severe disease and poorly tolerate invasive diagnostic procedures. This review examines recently reported risks for PJP in non-HIV populations and summarizes new diagnostic techniques.

RECENT FINDINGS

PJP is associated with immunomodulatory drug therapies, including monoclonal antibody therapies such as tumour necrosis factor α antagonists, and calcineurin inhibitors. Underlying disease states include solid-organ transplantation, connective tissue and rheumatologic disorders, inflammatory bowel disease, haematological malignancies, and solid tumours. Modern diagnostic techniques [conventional PCR, quantitative PCR, (1→3)-β-D-glucan assays, and PET] are reviewed with respect to predictive value and clinical utility. In particular, current literature regarding validation and specificity of molecular diagnostic techniques is summarized, including application to minimally invasive specimens.

SUMMARY

HIV-negative populations at risk for PJP can be identified. Conventional PCR increases diagnostic sensitivity but may detect asymptomatic colonization. Quantitative PCR demonstrates potential for distinguishing colonization from infection, but clinical validation is required. Serum (1→3)-β-D-glucan may be elevated in PJP, although standardized cut-off values for clinical infection have not been determined. Further validation of serum markers and molecular diagnostic methods is necessary for early and accurate diagnosis in non-HIV populations.