Response rate and molecular correlates to encorafenib and binimetinib in BRAF-V600E mutant high-grade glioma

PURPOSE

While fewer than 5% of high-grade gliomas (HGG) are BRAF-V600E mutated, these tumors are notable as BRAF-targeted therapy shows efficacy for some populations. The purpose of this study was to evaluate response to the combination of encorafenib with binimetinib in adults with recurrent BRAF-V600 mutated HGG.

PATIENTS AND METHODS

In this phase 2, open-label, Adult Brain Tumor Consortium (ABTC) trial (NCT03973918), encorafenib and binimetinib were administered at their FDA-approved doses continuously in 28-day cycles. Eligible patients were required to have high-grade glioma or glioblastoma with a BRAF-V600E alteration that was recurrent following at least one line of therapy including radiation.

RESULTS

Five patients enrolled between January 2020 and administrative termination in November 2021 (due to closure of the ABTC). Enrolled patients received treatment for 2-40 months; currently one patient remains on treatment. Centrally determined radiographic response rate was 60%, with one complete response and two partial responses. Methylation profiling revealed all tumors cluster most closely with anaplastic PXA. Transcriptional profile for MAPK-response signature was similar across all tumors at baseline and did not correlate with response in this small population. Circulating tumor DNA measured in plasma samples prior to treatment, during response, and upon progression showed feasibility of detection for the BRAF-V600E alteration. No new safety signal was detected.

CONCLUSIONS

Encorafenib and binimetinib exhibit positive tumor responses in patients with recurrent BRAF-V600E mutant HGG in this small series, warranting therapeutic consideration. Although toxicity remains a concern for BRAF-targeted therapies, no new safety signal was observed in these patients.

Druggable genomic landscapes of high-grade gliomas

Background

Despite the putatively targetable genomic landscape of high-grade gliomas, the long-term survival benefit of genomically-tailored targeted therapies remains discouraging.

Methods

Using glioblastoma (GBM) as a representative example of high-grade gliomas, we evaluated the clonal architecture and distribution of hotspot mutations in 388 GBMs from the Cancer Genome Atlas (TCGA). Mutations were matched with 54 targeted therapies, followed by a comprehensive evaluation of drug biochemical properties in reference to the drug's clinical efficacy in high-grade gliomas. We then assessed clinical outcomes of a cohort of patients with high-grade gliomas with targetable mutations reviewed at the Johns Hopkins Molecular Tumor Board (JH MTB; n = 50).

Results

Among 1,156 sequence alterations evaluated, 28.6% represented hotspots. While the frequency of hotspot mutations in GBM was comparable to cancer types with actionable hotspot alterations, GBMs harbored a higher fraction of subclonal mutations that affected hotspots (7.0%), compared to breast cancer (4.9%), lung cancer (4.4%), and melanoma (1.4%). In investigating the biochemical features of targeted therapies paired with recurring alterations, we identified a trend toward higher lipid solubility and lower IC50 in GBM cell lines among drugs with clinical efficacy. The drugs' half-life, molecular weight, surface area and binding to efflux transporters were not associated with clinical efficacy. Among the JH MTB cohort of patients with IDH1 wild-type high-grade gliomas who received targeted therapies, trametinib monotherapy or in combination with dabrafenib conferred radiographic partial response in 75% of patients harboring BRAF or NF1 actionable mutations. Cabozantinib conferred radiographic partial response in two patients harboring a MET and a PDGFRA/KDR amplification. Patients with IDH1 wild-type gliomas that harbored actionable alterations who received genotype-matched targeted therapy had longer progression-free (PFS) and overall survival (OS; 7.37 and 14.72 respectively) than patients whose actionable alterations were not targeted (2.83 and 4.2 months respectively).

Conclusion

While multiple host, tumor and drug-related features may limit the delivery and efficacy of targeted therapies for patients with high-grade gliomas, genotype-matched targeted therapies confer favorable clinical outcomes. Further studies are needed to generate more data on the impact of biochemical features of targeted therapies on their clinical efficacy for high-grade gliomas.

A multi-site phase I trial of Veliparib with standard radiation and temozolomide in patients with newly diagnosed glioblastoma multiforme (GBM)

PURPOSE

A multi-site Phase I trial was conducted to determine the safety, maximum tolerated dose, and pharmacokinetics (PK) of Veliparib, a Poly (ADP-ribose) polymerase [PARP] enzyme inhibitor, when administered with temozolomide (TMZ) alone and then with temozolomide and radiation (RT) in patients with newly diagnosed glioblastoma.

METHODS

Given the potential for myelosuppression when a PARP inhibitor is combined with chemotherapy, the first 6 patients accrued were given Veliparib 10 mg bid and TMZ 75 mg/m2/d daily for six weeks. If this was well tolerated, the same doses of Veliparib and TMZ would be tested along with standard radiation with plans to dose escalate the Veliparib in subsequent patient cohorts. Once a maximal tolerated dose was determined, a 78 patient phase II study was planned. Peripheral blood pharmacokinetics were assessed.

RESULTS

Twenty-four patients were enrolled. In the first 6 patients who received 6 weeks of TMZ with Veliparib only one dose limiting toxicity (DLT) occurred. The next 12 patients received 6 weeks of RT + TMZ + veliparib and 4/12 (33%) had dose limiting hematologic toxicities. As a result, Veliparib was reduced by 50% to 10 mg BID every other week, but again 3/3 patients had dose limiting hematologic toxicities. The trial was then terminated. The mean clearance (± SD) CL/F of Veliparib for the initial dose (27.0 ± 9.0 L/h, n = 16) and at steady-state for 10 mg BID (23.5 ± 10.4 L/h, n = 18) were similar. Accumulation for BID dosing was 56% (± 33%).

CONCLUSIONS

Although Veliparib 10 mg BID administered with TMZ 75 mg/m2 for six weeks was well tolerated, when this regimen was combined with standard partial brain irradiation it was severely myelosuppressive even when the dose was reduced by 50%. This study again highlights the potential of localized cranial radiotherapy to significantly increase hematologic toxicity of marginally myelosuppressive systemic therapies.

CEST2022: Amide proton transfer-weighted MRI improves the diagnostic performance of multiparametric non-contrast-enhanced MRI techniques in patients with post-treatment high-grade gliomas

New or enlarged lesions in malignant gliomas after surgery and chemoradiation can be associated with tumor recurrence or treatment effect. Due to similar radiographic characteristics, conventional-and even some advanced MRI techniques-are limited in distinguishing these two pathologies. Amide proton transfer-weighted (APTw) MRI, a protein-based molecular imaging technique that does not require the administration of any exogenous contrast agent, was recently introduced into the clinical setting. In this study, we evaluated and compared the diagnostic performances of APTw MRI with several non-contrast-enhanced MRI sequences, such as diffusion-weighted imaging, susceptibility-weighted imaging, and pseudo-continuous arterial spin labeling. Thirty-nine scans from 28 glioma patients were obtained on a 3 T MRI scanner. A histogram analysis approach was employed to extract parameters from each tumor area. Statistically significant parameters (P < 0.05) were selected to train multivariate logistic regression models to evaluate the performance of MRI sequences. Multiple histogram parameters, particularly from APTw and pseudo-continuous arterial spin labeling images, demonstrated significant differences between treatment effect and recurrent tumor. The regression model trained on the combination of all significant histogram parameters achieved the best result (area under the curve = 0.89). We found that APTw images added value to other advanced MR images for the differentiation of treatment effect and tumor recurrence.

In-vivo magnetic resonance spectroscopy of lactate as a non-invasive biomarker of dichloroacetate activity in cancer and non-cancer central nervous system disorders

The adverse effects of lactic acidosis in the cancer microenvironment have been increasingly recognized. Dichloroacetate (DCA) is an orally bioavailable, blood brain barrier penetrable drug that has been extensively studied in the treatment of mitochondrial neurologic conditions to reduce lactate production. Due to its effect reversing aerobic glycolysis (i.e., Warburg-effect) and thus lactic acidosis, DCA became a drug of interest in cancer as well. Magnetic resonance spectroscopy (MRS) is a well-established, non-invasive technique that allows detection of prominent metabolic changes, such as shifts in lactate or glutamate levels. Thus, MRS is a potential radiographic biomarker to allow spatial and temporal mapping of DCA treatment. In this systematic literature review, we gathered the available evidence on the use of various MRS techniques to track metabolic changes after DCA administration in neurologic and oncologic disorders. We included in vitro, animal, and human studies. Evidence confirms that DCA has substantial effects on lactate and glutamate levels in neurologic and oncologic disease, which are detectable by both experimental and routine clinical MRS approaches. Data from mitochondrial diseases show slower lactate changes in the central nervous system (CNS) that correlate better with clinical function compared to blood. This difference is most striking in focal impairments of lactate metabolism suggesting that MRS might provide data not captured by solely monitoring blood. In summary, our findings corroborate the feasibility of MRS as a pharmacokinetic/pharmacodynamic biomarker of DCA delivery in the CNS, that is ready to be integrated into currently ongoing and future human clinical trials using DCA.

Transient Opening of the Blood-Brain Barrier by Vasoactive Peptides to Increase CNS Drug Delivery: Reality Versus Wishful Thinking?

BACKGROUND

The blood-brain barrier inhibits the central nervous system penetration of 98% of small molecule drugs and virtually all biologic agents, which has limited progress in treating neurologic disease. Vasoactive peptides have been shown in animal studies to transiently disrupt the blood-brain barrier and regadenoson is currently being studied in humans to determine if it can improve drug delivery to the brain. However, many other vasoactive peptides could potentially be used for this purpose.

METHODS

We performed a review of the literature evaluating the physiologic effects of vasoactive peptides on the vasculature of the brain and systemic organs. To assess the likelihood that a vasoactive peptide might transiently disrupt the blood-brain barrier, we devised a four-tier classification system to organize the available evidence.

RESULTS

We identified 32 vasoactive peptides with potential blood-brain barrier permeabilityaltering properties. To date, none of these are shown to open the blood-brain barrier in humans. Twelve vasoactive peptides increased blood-brain barrier permeability in rodents. The remaining 20 had favorable physiologic effects on blood vessels but lacked specific information on permeability changes to the blood-brain barrier.

CONCLUSION

Vasoactive peptides remain an understudied class of drugs with the potential to increase drug delivery and improve treatment in patients with brain tumors and other neurologic diseases. Dozens of vasoactive peptides have yet to be formally evaluated for this important clinical effect. This narrative review summarizes the available data on vasoactive peptides, highlighting agents that deserve further in vitro and in vivo investigations.

Lymphocyte depletion rate as a biomarker of radiation dose to circulating lymphocytes during fractionated partial-body radiotherapy

Purpose

Radiation causes exponential depletion of circulating lymphocyte populations; in turn, radiation-induced lymphopenia is associated with worse survival for many solid tumors, possibly owing to attenuated antitumor immune responses. Identifying reliable and reproducible methods of calculating the radiation dose to circulating immune cells may facilitate development of techniques to reduce the risk and severity of radiation-induced toxic effects to circulating lymphocytes.

Methods and Materials

Patient-specific lymphocyte loss rates were derived from a clinical data set including 684 adult patients with solid tumors. Multivariable linear regression was used to model the relationship between the lymphocyte loss rate and physical parameters of the radiation plan that determine circulating blood dose.

Results

During partial-body radiation, lymphocyte loss rates are determined by physical parameters of the radiation plan that reflect radiation exposure to circulating cells, including target volume size, dose per fraction squared, and anatomic site treated. Differences in observed versus predicted lymphocyte loss rates may be partly explained by variations in concurrent chemotherapy regimens.

Conclusions

We describe a novel method of using patient-specific lymphocyte loss kinetics to approximate the effective radiation dose to circulating lymphocytes during focal fractionated photon radiation therapy. Clinical applications of these findings include the early identification of patients at particularly high risk of severe radiation-induced lymphopenia based on physical parameters of the radiation therapy plan.

Glioblastoma Clinical Trials: Current Landscape and Opportunities for Improvement

Therapeutic advances for glioblastoma have been minimal over the past 2 decades. In light of the multitude of recent phase III trials that have failed to meet their primary endpoints following promising preclinical and early-phase programs, a Society for Neuro-Oncology Think Tank was held in November 2020 to prioritize areas for improvement in the conduct of glioblastoma clinical trials. Here, we review the literature, identify challenges related to clinical trial eligibility criteria and trial design in glioblastoma, and provide recommendations from the Think Tank. In addition, we provide a data-driven context with which to frame this discussion by analyzing key study design features of adult glioblastoma clinical trials listed on ClinicalTrials.gov as "recruiting" or "not yet recruiting" as of February 2021.

High-grade glioma therapy: adding flexibility in trial design to improve patient outcomes

INTRODUCTION

Outcomes for patients with high grade gliomas have changed little over the past thirty years. This realization prompted renewed efforts to increase flexibility in the design and conduct of clinical brain tumor trials.

AREAS COVERED

This manuscript reviews the development of clinical trial methods, challenges and considerations of flexible clinical trial designs, approaches to improve identification and testing of active agents for high grade gliomas, and evaluation of their delivery to the central nervous system.

EXPERT OPINION

Flexibility can be introduced in clinical trials in several ways. Flexible designs tout smaller sample sizes, adaptive modifications, fewer control arms, and inclusion of multiple arms in one study. Unfortunately, modifications in study designs cannot address two challenges that are largely responsible for the lack of progress in treating high grade gliomas: 1) the identification of active pharmaceutical agents and 2) the delivery of these agents to brain tumor tissue in therapeutic concentrations. To improve the outcomes of patients with high grade gliomas efforts must be focused on the pre-clinical screening of drugs for activity, the ability of these agents to achieve therapeutic concentrations in non-enhancing tumors, and a willingness to introduce novel compounds in minimally pre-treated patient populations.

Multimodal platform for assessing drug distribution and response in clinical trials

BACKGROUND

Response to targeted therapy varies between patients for largely unknown reasons. Here, we developed and applied an integrative platform using mass spectrometry imaging (MSI), phosphoproteomics, and multiplexed tissue imaging for mapping drug distribution, target engagement, and adaptive response to gain insights into heterogeneous response to therapy.

METHODS

Patient-derived xenograft (PDX) lines of glioblastoma were treated with adavosertib, a Wee1 inhibitor, and tissue drug distribution was measured with MALDI-MSI. Phosphoproteomics was measured in the same tumors to identify biomarkers of drug target engagement and cellular adaptive response. Multiplexed tissue imaging was performed on sister sections to evaluate spatial co-localization of drug and cellular response. The integrated platform was then applied on clinical specimens from glioblastoma patients enrolled in the phase 1 clinical trial.

RESULTS

PDX tumors exposed to different doses of adavosertib revealed intra- and inter-tumoral heterogeneity of drug distribution and integration of the heterogeneous drug distribution with phosphoproteomics and multiplexed tissue imaging revealed new markers of molecular response to adavosertib. Analysis of paired clinical specimens from patients enrolled in the phase 1 clinical trial informed the translational potential of the identified biomarkers in studying patient's response to adavosertib.

CONCLUSIONS

The multimodal platform identified a signature of drug efficacy and patient-specific adaptive responses applicable to preclinical and clinical drug development. The information generated by the approach may inform mechanisms of success and failure in future early phase clinical trials, providing information for optimizing clinical trial design and guiding future application into clinical practice.

Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers

Background

The benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown.

Methods

We undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible patients had radiologic/cytologic LMM and Eastern Cooperative Oncology Group performance status 0–1. Pembrolizumab was administered intravenously at 200 mg q3W until disease progression/unacceptable toxicity. The primary endpoint was central nervous system (CNS) response after four cycles, defined radiologically/cytologically/clinically. Serial cerebrospinal fluid (CSF) was assessed for tumor-derived DNA (t-DNA) aneuploidy and cytokines.

Results

Thirteen of a planned 16 patients were treated between April 2017 and December 2019. The study closed early for poor accrual. Median age was 57 years (range: 22–79). Sixty-two percent of patients had tumors not traditionally ICI-responsive (hormone-receptor (HR)-positive breast carcinoma=39%; high-grade glioma=23%), while 38% had ICI-responsive tumors (non-small cell lung cancer (NSCLC)=23%, head and neck carcinoma=8%, cutaneous squamous carcinoma (CSC)=8%). CNS response was observed in 38% of patients at 12 weeks (95% CI 13.9% to 68.4%) by pre-defined criteria and LM-RANO, and 2 achieved durable complete responses (CSC=1, overall survival (OS) 3+ years; NSCLC=1, OS 9 months). Median CNS progression-free survival and OS was 2.9 months (95% CI 1.3 to NR) and 4.9 months (95% CI 3.7 to NR), respectively. Grade 3+ treatment-related adverse events occurred in 15% of patients. Sensitivity for LMM detection by t-DNA and cytopathology was 84.6% (95% CI 54.6% to 98.1%) and 53.9% (95% CI 25.1% to 80.8%), respectively. Pre-therapy and on-therapy CSF cytokine analysis demonstrated complete responders clustered together.

Conclusions

Pembrolizumab conferred a 38% CNS response rate in patients with LMM, a tolerable safety profile, and deep responses in selected patients with ICI-responsive tumors. CSF t-DNA may be sensitive for LMM detection, and immunologic subsets of CNS response warrant further study.

Trial registration number

NCT03091478

The 1994 National Cancer Institute’s strategy to fund multi-institutional, multidisciplinary consortia to design and conduct early phase clinical trials in patients with high grade gliomas

2003

Background: : In the early 1990’s, the NCI suspended activities of the Brain Tumor Study Group seeking to shift clinical brain tumor research from phase III trials to innovative and correlative rich phase I/II studies. In 1994, NCI funded three early phase brain tumor consortia, later reduced to two consortia in 1999 and one in 2009. In 2020, the NCI announced it would discontinue funding the brain tumor consortium and emphasize pre-clinical glioblastoma drug development (RFA-CA-20-047). Methods: The activities of the New Approaches to Brain Tumor Therapy (NABTT: 1994-2009) and Adult Brain Tumor Consortium (ABTC: 2009-2021) were summarized using data from the Central Operations Office that served the consortia for 27 years. Results: From 1994-2020, 48 consortium meetings were held to discuss, develop, conduct, and evaluate early phase clinical trials. These involved multidisciplinary brain tumor experts (neuro-oncologists, neurosurgeons, radiation oncologists, neuropathologists, statisticians, pharmacologists, imaging experts, immunologists, etc) from 27 US academic centers and hospitals. 85 clinical trials were written, approved by NCI and the Brain Malignancy Steering Committee, and conducted. Most trials evaluated NCI-provided therapeutic agents. 34 trials were conducted in collaboration with 27 pharmaceutical companies eager to develop malignant brain tumor therapeutics; for 9 of these the consortia held the IND. 4870 patients were accrued: 3375 to therapeutic and 1495 to non-therapeutic studies. 49 grant proposals were submitted to fund consortium activities with a 46% approval rate. 91 peer reviewed manuscripts were published, with 174 presentations and abstracts. 18 pharmaceutical symposia were conducted to attract new agents toward early phase brain tumor research. Consortia sponsored 34 Guest Lectureships and multidisciplinary symposia to focus on relevant critical research areas. Additionally, the consortia provided unique opportunities for young faculty to lead multicenter NABTT/ABTC trials with appropriate support and mentorship. Conclusions: Therapeutic progress for high grade gliomas has been slow for many reasons (95% of systemically administered agents do not penetrate the blood-brain barrier, inherent treatment resistance, immunologically “cold” phenotype, etc). NABTT/ABTC focused multidisciplinary, multi-institutional experts on major challenges unique to brain tumor research. The consortia developed innovative early phase clinical studies rich in correlative endpoints, fostered research grants, hosted relevant topical symposia, and provided leadership roles for young investigators while bringing together the NCI, industry, and committed multidisciplinary academicians to explore novel therapeutic options for patients with primary brain tumors.

CODEL: phase III study of RT, RT + TMZ, or TMZ for newly diagnosed 1p/19q codeleted oligodendroglioma. Analysis from the initial study design

BACKGROUND

We report the analysis involving patients treated on the initial CODEL design.

METHODS

Adults (>18) with newly diagnosed 1p/19q World Health Organization (WHO) grade III oligodendroglioma were randomized to radiotherapy (RT; 5940 centigray ) alone (arm A); RT with concomitant and adjuvant temozolomide (TMZ) (arm B); or TMZ alone (arm C). Primary endpoint was overall survival (OS), arm A versus B. Secondary comparisons were performed for OS and progression-free survival (PFS), comparing pooled RT arms versus TMZ-alone arm.

RESULTS

Thirty-six patients were randomized equally. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients progressed, versus 37.5% (9/24) on the RT arms. PFS was significantly shorter in TMZ-alone patients compared with RT patients (hazard ratio [HR] = 3.12; 95% CI: 1.26, 7.69; P = 0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) on the RT arms. OS did not statistically differ between arms (comparison underpowered). After adjustment for isocitrate dehydrogenase (IDH) status (mutated/wildtype) in a Cox regression model utilizing IDH and RT treatment status as covariables (arm C vs pooled arms A + B), PFS remained shorter for patients not receiving RT (HR = 3.33; 95% CI: 1.31, 8.45; P = 0.011), but not OS ((HR = 2.78; 95% CI: 0.58, 13.22, P = 0.20). Grade 3+ adverse events occurred in 25%, 42%, and 33% of patients (arms A, B, and C). There were no differences between arms in neurocognitive decline comparing baseline to 3 months.

CONCLUSIONS

TMZ-alone patients experienced significantly shorter PFS than patients treated on the RT arms. The ongoing CODEL trial has been redesigned to compare RT + PCV versus RT + TMZ.

Adult precision medicine: learning from the past to enhance the future

Despite therapeutic advances for other malignancies, gliomas remain challenging solid tumors to treat. Complete surgical resection is nearly impossible due to gliomas’ diffuse infiltrative nature, and treatment is hampered by restricted access to the tumors due to limited transport across the blood–brain barrier. Recent advances in genomic studies and next-generation sequencing techniques have led to a better understanding of gliomas and identification of potential aberrant signaling pathways. Targeting the specific genomic abnormalities via novel molecular therapies has opened a new avenue in the management of gliomas, with encouraging results in preclinical studies and early clinical trials. However, molecular characterization of gliomas revealed significant heterogeneity, which poses a challenge for targeted therapeutic approaches. In this context, leading neuro-oncology researchers and clinicians, industry innovators, and patient advocates convened at the inaugural annual Remission Summit held in Orlando, FL in February 2019 to discuss the latest advances in immunotherapy and precision medicine approaches for the treatment of adult and pediatric brain tumors and outline the unanswered questions, challenges, and opportunities that lay ahead for advancing the duration and quality of life for patients with brain tumors. Here, we provide historical context for precision medicine in other cancers, present emerging approaches for gliomas, discuss their limitations, and outline the steps necessary for future success. We focus on the advances in small molecule targeted therapy, as the use of immunotherapy as an emerging precision medicine modality for glioma treatment has recently been reviewed by our colleagues.

A Phase II and Pharmacodynamic Trial of RO4929097 for Patients With Recurrent/Progressive Glioblastoma

BACKGROUND

Cancer stem-like cells are a major cause of resistance to therapy in patients with glioblastoma (GBM) as well as other cancers. Tumor cells are maintained in a stem-like proliferative state in large part through the Notch signaling pathway. The function of this pathway in turn depends on gamma secretase activity. Inhibition of this enzyme therefore inhibits the Notch pathway and tumor growth as measured by a reduction in the formation of brain tumor neurospheres in murine models. RO4929097 is an oral gamma secretase inhibitor.

OBJECTIVE

To estimate the 6-mo progression-free survival rate (PFS6) in patients with progressive GBM and to inhibit by 50% the generation of neurospheres in fresh tissue resected from patients treated with RO4929097.

METHODS

In this phase II and pharmacodynamic study, patients with recurrent GBM received RO4929097 in a study of 2 groups. Group A patients had unresectable disease and received drug in a standard phase II design. Group B patients had resectable disease and received drug before and after surgical resection. Endpoints included PFS6 and the inhibition of neurosphere formation in the resected tumor samples.

RESULTS

A total of 47 patients received treatment, 7 of whom had tumor resection. The PFS6 was 4%, and the inhibition of neurosphere formation occurred in 1 of 7 patient samples.

CONCLUSION

RO4929097 was inactive in recurrent GBM patients and demonstrated minimal inhibition of neurosphere formation in fresh tissue samples.

Quantifying the utility of a multidisciplinary neuro-oncology tumor board

OBJECTIVE

There has been limited research on the efficacy of multidisciplinary tumor boards (MDTBs) in improving the treatment of patients with tumors affecting the nervous system. The objective of the present study was to quantify the utility of MDTBs in providing alternative diagnostic interpretations and treatment plans for this patient population.

METHODS

The authors performed a prospective study of patients in 4 hospitals whose cases were discussed at MDTBs between July and November 2019. Patient demographic data, diagnoses, treatment plans, and eligibility for clinical trials were recorded, among other variables.

RESULTS

A total of 176 cases met eligibility criteria for study inclusion. The majority (53%) of patients were male, and the mean patient age was 52 years. The most frequent diagnosis was glioblastoma (32.4%). Among the evaluable cases, MDTBs led to 38 (21.6%) changes in image interpretation and 103 (58.2%) changes in patient management. Additionally, patients whose cases were discussed at MDTBs had significantly shorter referral times than patients whose cases were not discussed (p = 0.024).

CONCLUSIONS

MDTB discussions led to significant numbers of diagnostic and treatment plan changes as well as shortened referral times, highlighting the potential clinical impact of multidisciplinary care for patients with nervous system tumors.

Evidence for persistent radiation-related injury to the immune system in patients with local breast cancer

e15189

Background: Clinical data in multiple tumors has demonstrated that the inadvertent radiation of circulating lymphocytes causes grade III-IV lymphopenia which is associated with worse outcomes in cancer patients and failure to respond to immunologic interventions. Murine data from our lab demonstrated that radiation to the brain results in striking changes in the anatomy and cellularity of distant unirradiated lymph nodes. This study was designed to understand the relationship between local radiation and the depletion of distant unirradiated lymph nodes in humans which has not been previously studied. Methods: Adult women with breast cancer who had undergone prior mastectomy with pathology, labs, and radiation data available at our institution were enrolled at the time of their deep inferior epigastric perforator artery (DIEP) flap reconstruction. During reconstruction, a single abdominal lymph node was extracted, and subsequently formalin fixed. The pre- and post-treatment lymph nodes of radiated and non-radiated patients were presented in a blinded manner to the hematopathologist. The pathologist described each lymph node and graded the lymph node density as (1) low, (2) low-normal, (3) normal, or (4) high. Results: Seven women have been enrolled (median age 50; range 31-55) with AJCC tumor stages from 1a – 3b (five are hormone positive, and two are triple negative). The reconstruction was completed on average 488.71 + 224.57 days after initial mastectomy. Three of the women received neoadjuvant chemotherapy, and five received adjuvant chemotherapy. Five of the seven women had received radiation (mean 50.9 + 5.6 Gy). The baseline median LN density score in all patients was 4 (range 1-4), with a post mean LN density of 1.2 + 0.4 in the radiation group compared to a mean score of 3 + 1.4 in the control group. Conclusions: Systemic lymphocyte counts remain relatively stable but lymph node density is markedly lower than baseline in 80% of patients who received chest wall irradiation consistent with data from animal model studies. It is important to note that this effect on the nodes is seen long after the radiation has been completed. [Table: see text]

Updated safety phase I trial of anti-LAG-3 alone and in combination with anti-PD-1 in patients with recurrent GBM

2512

Background: Preclinical GBM data targeting the checkpoint molecule Lag-3 have shown promising anti-tumor immune response with resultant improved survival when combined with anti-PD-1. Here we report our experience from a multi-arm safety study in patients with recurrent GBM treated with anti-Lag-3 and in combination with anti-PD-1. Methods: A phase I, open label, multicenter, multi-arm dose-finding/safety study of anti-LAG-3 (BMS-986016) alone or in combination with anti-PD-1 in patients at first recurrence of GBM was carried out in The Adult Brain Tumor Consortium (ABTC) (1501). The primary objectives were safety and to define MTD (DLT rate < 33%) for both the mono and combination arms. The major secondary objective was efficacy. The key inclusion criteria were: adults with first recurrence of GBM following RT+TMZ, TLC≥1000/ul, KPS≥ 60%, on a stable corticosteroid regimen, measurable disease, and written informed consent. Three pre specified dose levels of anti-Lag-3 at 80mg, 160mg, and 800mg were tested. Anti-PD-1was given at a flat dose of 240 mg in combination with anti-LAG-3 at 80 mg and 160 mg. Results: To date, the phase I portion of study completed its accrual and 33 patients were enrolled into the anti-LAG-3 alone or in combination with anti-PD-1 arms. The median age and KPS was 56 and 90 respectively. 39% tumors were MGMT methylated and the median treatment cycle was 3. The highest safe dose for Anti-LAG-3 alone is 800 mg without a DLT. Two DLT were observed in combination arms of Anti-LAG-3 +anti-PD-1 (80 mg/240mg), a grade 3 muscle weakness and a grade 4 edema. Three DLTs were observed in the higher Anti-LAG-3 + anti-PD-1 group (160 mg/240mg): grade 3 hypertension, syncope, and edema. 80% of the DLTs occurred after cycle 2 of the treatment. The estimated overall mOS was 8 months. Seven (44%) patients in the combination arm are still alive and 3 out of the 7 are living beyond 20 months suggesting a subset benefit. Conclusions: The phase I part of trial has completed enrollment. The MTD is 800mg for anti-LAG-3 as a monotherapy. For the combination arms, 160 mg of Anti-LAG-3 and 240 mg of anti-PD-1 was the MTD. DLTs were late onset events. Clinical trial information: NCT02658981 .

Intratumoral drug distribution of adavosertib in patients with glioblastoma: Interim results of phase I study

2568

Background: Wee1 is a key regulator of the G2/M checkpoint and is frequently overexpressed in glioblastoma (GB). Adavosertib is a first-in-class oral, small molecule inhibitor of Wee1 that acts primarily as a DNA damage sensitizer. A phase I clinical trial was conducted to evaluate its safety and establish the recommended phase II dosing. Studies were undertaken to evaluate whether potentially therapeutic concentrations of the drug are achieved in recurrent tumor and adjacent non-enhancing brain regions with presumed intact blood-brain barrier (BBB). Methods: Twelve patients received five daily doses of adavosertib pre-operatively at either the maximum tolerated dose (MTD) for concurrent radiation or adjuvant temozolomide. Tissue from contrast enhancing (CE) and non-enhancing (NE) brain regions was obtained for analysis during surgical resection. A second stage is being conducted using microdialysis (MD) to facilitate continuous sampling of extracellular fluid (ECF) and measuring free drug concentrations in: normal-appearing brain, contrast enhancing tumor, and a peritumoral T2 hyperintense area. The concentration of total adavosertib in plasma and tissue homogenates and free drug in ECF were determined by validated LC/MS/MS methods. Results: Geometric mean concentrations of adavosertib after a 200 mg dose were 644 ng/mL and 119 ng/mL in CE and NE tissue specimens, respectively (6 patients). At the 425 mg dose, the mean concentrations were 3,576 ng/mL in CE tissue and 885 ng/mL in NE tissue (6 patients). MD was performed in 2 patients. Samples from functional MD catheters were collected from NE brain in patient no. 1 and from two NE areas and a FLAIR hyperintense region in patient no. 2, with the following results in the table. Conclusions: The total drug concentration in tissue samples was notably lower in regions of the brain with a relatively intact BBB as compared to contrast enhancing tissue. Concentrations of adavosertib measured by MD vary markedly depending on catheter location. Free drug levels in ECF within brain with a functional BBB, although considerably lower than total drug levels in tissue, were 2-10 times below the previously reported IC50 for antiproliferative activity against sensitive GB cell lines (127 ng/mL). Whether or not the target of the drug is effectively inhibited at these concentrations remains to be demonstrated. Clinical trial information: NCT01849146 . [Table: see text]

Anti-PD-1 for patients with leptomeningeal metastasis from advanced solid tumors: Efficacy, safety, and biomarkers of response

e14506

Background: Leptomeningeal metastasis (LMM) from solid tumors are rare and often refractory to standard therapies. Pembrolizumab (anti-PD-1) has efficacy in patients (pts) with brain metastases from ICI-responsive tumors, however pts with LMM are often excluded from ICI trials. We hypothesized that: 1. Pembrolizumab will lead to CNS response in LMM, and 2. Genomic/immunologic analyses on CSF could identify CNS biomarkers of response. Methods: We conducted an investigator-initiated open-label phase 2 trial of Pembrolizumab in pts with LMM from any solid tumor (NCT03091478). Eligible pts had: LMM on MRI ( > 3mm lesion) or CSF cytology, ECOG PS ≤1, and were PD-naïve. Prior RT to LMM was allowed > 3 months before study start or to non-target areas. Pembrolizumab was administered IV 200mg q3W until disease progression/unacceptable toxicity. The primary endpoint was CNS response after 12 weeks, defined as radiologic (RECIST 1.1)/cytologic/clinical response to therapy. Serial CSF samples were assessed by chromosomal copy number changes using a PCR-based approach (RealSeqS) to detect tumor-derived DNA (CSF-tDNA), and 16-color flow cytometry. Results: Thirteen of a planned 18 pts were treated 04/2017-12/2019, the study was closed early for low accrual. Median age was 58 years (22-79), 53% were female. Pts had breast carcinoma (38%, n = 5), NSCLC (23%, n = 3), high-grade glioma (23%, n = 3), HNSCC (8%, n = 1) and cutaneous squamous cell carcinoma (8%, n = 1). Median no. of prior therapies was 4 (0-8), 76% of pts had prior RT to LMM. CNS response was seen in 38% of pts (5/13: 2 = complete response (NSCLC; Squamous skin); 3 = stable disease (NSCLC, Glioma, HER2+BC) by RECIST 1.1. Treatment-related adverse events were seen in 31% (4/13) of pts, 15% (2/13) G3+ (fatigue = 1, infection = 1). CSF cytology was negative at ICI start in 6 cases, but positive by CSF-tDNA in 5/6 cases. In addition, CSF-tDNA levels can correlate with disease status. CSF flow cytometry demonstrated increase in CD45R0+ activated memory T-cells, and a shift from immature to antibody-secreting B-cells in both pts with CRs in LMM. Conclusions: Pembrolizumab was well-tolerated and demonstrated anti-tumor activity in pts with LMM in ICI-responsive tumors. Correlative analyses identified CSF-tDNA can potentially be used from diagnosis to longitudinally monitor LMM; and that T and B cell populations may be enriched in the CSF of pts whose LMM regressed. These findings support inclusion of pts with LMM in ICI studies and interrogation of CSF biomarkers. Clinical trial information: NCT03091478.

RAF and MEK inhibitor therapy in adult patients with brain tumors: a case-based overview and practical management of adverse events

Targeted therapy has gained mainstream attention with notable successes against specific genetic mutations in many cancers. One particular mutation, the BRAF V600E mutation, is present in a small subset of gliomas in adults. Although clinical experience and trial data of RAF-targeted therapy in adults with glioma are lacking at this time, the poor prognosis of adult high-grade glioma has led neuro-oncology practitioners to consider the use of targeted therapy in these patients. In this manuscript, we describe the use of RAF and MEK inhibitors in adults with recurrent glioma. We discuss the utility of these agents, describe their toxicities, and give examples of management strategies. Given the significant toxicities of RAF and MEK inhibitors, along with the long potential duration of treatment, neuro-oncology providers should counsel patients carefully before initiating therapy and monitor them closely while undergoing treatment with RAF-targeted therapy.

Correction to: White matter changes in primary central nervous system lymphoma patients treated with high-dose methotrexate with or without rituximab

The following discrepancies and errors were found in the original publication.

Brain Metastases as a First Site of Recurrence in Patients Receiving Chemotherapy with Controlled Systemic Cancer: a Critical but Under-Recognized Clinical Scenario

PURPOSE OF REVIEW

As the treatment of many malignancies has improved, brain metastases (BM) have been observed as a site of the first recurrence in patients with controlled systemic cancers. This suggests that while the administered chemotherapy is effective against systemic cancer, drug concentrations in the central nervous system (CNS) are likely too low to be effective. These findings are in accord with data suggesting that more than 98% of FDA-approved drugs on the market today are unable to cross the blood-brain barrier (BBB).

RECENT FINDINGS

This retrospective literature review was conducted to estimate the proportion of patients with non-small lung cancer, breast cancer, and melanoma who develop BM as their initial site of recurrence while their systemic cancers are well controlled. Of 267 studies screened, 12 studies fit criteria for inclusion. These 12 studies reported on 923 patients. According to compiled data across these studies, 16% of patients on chemotherapy with stable or responding systemic cancer developed isolated BM as their initial site of relapse. These findings strongly suggest that while chemotherapy controlled systemic cancer, drug concentrations within the CNS were low enough to allow disease progression. Ultimately, reducing the incidence of BM in these patients will require novel therapeutic approaches that facilitate drug entry through an intact BBB early in their treatment.

Comprehensive Analysis of the Kinetics of Radiation-Induced Lymphocyte Loss in Patients Treated with External Beam Radiation Therapy

Radiation-induced lymphopenia (RIL) is associated with worse survival in patients with solid tumors, as well as lower response rates to checkpoint inhibitors. While single-fraction total-body irradiation is known to result in exponential decreases in the absolute lymphocyte count (ALC), the kinetics of lymphocyte loss after focal fractionated exposures have not previously been characterized. In the current study, lymphocyte loss kinetics was analyzed among patients undergoing focal fractionated radiotherapy for clinical indications. This registry-based study included 419 patients who received either total-body irradiation (TBI; n = 30), stereotactic body radiation therapy (SBRT; n = 73) or conventionally fractionated chemoradiation therapy (CFRT; n = 316). For each patient, serial ALCs were plotted against radiotherapy fraction number. The initial three weeks of treatment for CFRT patients and the entirety of treatment for SBRT and TBI patients were fit to exponential decay in the form ALC(x) = ae^-bx, where ALC(x) is the ALC after x fractions. From those fits, fractional lymphocyte loss (FLL) was calculated as FLL = (1 - e^-b) * 100, and multivariable regression was performed to identify significant correlates of FLL. Median linearized R² when fitting the initial fractions was 0.98, 0.93 and 0.97 for patients receiving TBI, SBRT and CFRT, respectively. In CFRT patients, apparent ALC loss rate slowed after week 3. Fitting ALC loss over the entire CFRT course therefore required the addition of a constant term, "c". For TBI and SBRT patients, treatment ended during the pure exponential decay phase. Initial FLL varied significantly with treatment technique. Mean FLL was 35.5%, 24.3% and 10.77% for patients receiving TBI, SBRT and CFRT, respectively (P < 0.001). Significant correlates of FLL varied by site and included field size, dose per fraction, mean spleen dose, chemotherapy backbone and age. Finally, total percentage ALC loss during radiotherapy was highly correlated with FLL (P < 0.001). Lymphocyte depletion kinetics during the initial phase of fractionated radiotherapy are characterized by pure exponential decay. Initial FLL is strongly correlated with radiotherapy planning parameters and total percentage ALC loss. The two groups with the highest FLL received no concurrent chemotherapy, suggesting that ALC loss can be a consequence of radiotherapy alone. This work may assist in selecting patients for adaptive radiotherapy approaches to mitigate RIL risk.

Concurrent BRAF/MEK Inhibitors in BRAF V600-Mutant High-Grade Primary Brain Tumors

BRAF V600 mutations are being identified in patients with primary brain tumors more often as molecular testing becomes widely available. Targeted treatment with BRAF inhibitors has been attempted in individual cases with some responses, whereas others showed no response or developed resistance. Preclinical work suggests that gliomas could be more responsive to the concurrent use of BRAF and MEK inhibition for MAP kinase pathway suppression. This report presents 2 cases of malignant brain tumors with BRAF V600E mutations that were resistant to radiation and temozolomide, and reports on their response to targeted treatment with the BRAF and MEK inhibitors dabrafenib and trametinib. One patient with an anaplastic pleomorphic xanthoastrocytoma experienced a partial response for 14 months, demonstrated by progressive tumor shrinkage and clinical improvement; however, this was followed by clinical and radiographic progression. The patient with glioblastoma continued to have stable disease after 16 months of treatment. These cases are encouraging in a disease that urgently needs new treatments. Further work is necessary to understand response rates, duration, and survival in primary brain tumors.

BRAF Mutations and the Utility of RAF and MEK Inhibitors in Primary Brain Tumors

BRAF mutations have been identified as targetable, oncogenic mutations in many cancers. Given the paucity of treatments for primary brain tumors and the poor prognosis associated with high-grade gliomas, BRAF mutations in glioma are of considerable interest. In this review, we present the spectrum of BRAF mutations and fusion alterations present in each class of primary brain tumor based on publicly available databases and publications. We also summarize clinical experience with RAF and MEK inhibitors in patients with primary brain tumors and describe ongoing clinical trials of RAF inhibitors in glioma. Sensitivity to RAF and MEK inhibitors varies among BRAF mutations and between tumor types as only class I BRAF V600 mutations are sensitive to clinically available RAF inhibitors. While class II and III BRAF mutations are found in primary brain tumors, further research is necessary to determine their sensitivity to third-generation RAF inhibitors and/or MEK inhibitors. We recommend that the neuro-oncologist consider using these drugs primarily in the setting of a clinical trial for patients with BRAF-altered glioma in order to advance our knowledge of their efficacy in this patient population.

Patterns of bevacizumab use in patients with glioblastoma: an online survey among experts in neuro-oncology

Background

Bevacizumab (BEV) received accelerated FDA approval in 2009 for the treatment of recurrent glioblastoma (rGBM). Unfortunately, prospective randomized controlled phase 3 studies (AVAglio and Radiation Therapy Oncology Group 0825 in newly diagnosed, European Organisation for Research and Treatment of Cancer 26101 in rGBM) failed to show an overall survival benefit with BEV added to standard therapy. In light of these data, we aimed to capture current utilization patterns and perceived value of BEV in the treatment of GBM among experts in the field.

Methods

An online questionnaire comprising 14 multiple choice questions was sent out in spring 2017 to 207 oncologists/neuro-oncologists treating patients with GBM at all National Cancer Institute-designated cancer centers in the United States.

Results

Sixty-two of 207 (30%) invitees responded (by training, 70% neuro-oncologists, 20% medical oncologists, 10% pediatric oncologists/neuro-oncologists). Participants reported use of BEV most frequently in rGBM for control of edema (85% of respondents) and/or when no other treatment options were available (68%). BEV is rarely used in newly diagnosed GBM (<5% of cases by 78% respondents and in 5% to 10% cases by 15% respondents). Sixty-six percent of participants indicated that they thought BEV improved symptoms, 30% that it improved symptoms and survival, 3% that it had no benefit in GBM patients.

Conclusion

In this cross-sectional online survey we found that among neuro-oncology experts in the United States in 2017, BEV is predominantly utilized in select patients with rGBM, and is only rarely used in a small subgroup of patients with newly diagnosed GBM for control of edema. The low response rate may have introduced a nonresponse bias.

Comprehensive analysis of lymphocyte loss kinetics in patients treated with focal fractionated radiation therapy

e14191

Background: Radiation (RT)-induced lymphopenia (RIL) is associated with worse survival in patients with solid tumors as well as lower response rates to checkpoint inhibitors. This analysis aimed to model the kinetics of lymphocyte depletion during RT to assist in predicting RIL risk. Methods: This registry-based study included 419 patients who received either total body irradiation (TBI; n = 30), stereotactic body RT (SBRT; n = 73), or conventional chemoradiation (CRT; n = 316). For each patient, serial absolute lymphocyte counts (ALCs) were plotted against RT fraction number. The initial 3 weeks of treatment for conventionally irradiated patients and the entirety of treatment for SBRT and TBI patients were fit to exponential decay in the form ALC(x) = ae-bx. From those fits, percent per fraction loss in ALC (PFLAC) was calculated as PFLAC = (1 – e-b)*100, and multivariable regression was performed to find its significant predictors. Results: Curves were well fitted by exponential decay for all RT techniques (median linearized R2 0.98, 0.93, and 0.97 for patients treated with TBI, SBRT, and CRT, respectively). In CRT patients, apparent ALC loss rate slowed after week 3, potentially due to lymphocyte repopulation or other factors. TBI and SBRT patients completed RT before the end of the exponential decay phase, and their ALC loss rates remained unchanged throughout RT. Initial PFLAC varied significantly with treatment technique. Mean PFLAC was 35.5%, 24.3%, and 10.77% for patients treated with TBI, SBRT, and CRT, respectively (p < 0.001). Significant predictors of PFLAC varied by site and included field size, dose per fraction, mean spleen dose, chemotherapy backbone, and age. In pancreas cancer patients, gemcitabine was associated with a higher PFLAC (mean = 10.7) than 5-FU (mean = 8.3) after adjustment for covariates (p < 0.001). Finally, total % ALC loss during RT was highly correlated with PFLAC (p < 0.001). Conclusions: Lymphocyte depletion kinetics during the initial phase of fractionated RT are characterized by pure exponential decay. Initial PFLAC is strongly correlated with RT planning parameters and predicts total % ALC loss. The highest ALC loss rates were associated with RT-only regimens, implying that concurrent chemotherapy is not solely responsible for lymphopenia in patients receiving CRT. This work may also assist in selecting patients for adaptive RT approaches to mitigate RIL risk.

Safety and activity of a first-in-class oral HIF2-alpha inhibitor, PT2385, in patients with first recurrent glioblastoma (GBM)

2027

Background: Hypoxia inducible factor 2-alpha (HIF2a) mediates cellular responses to hypoxia and is overexpressed in GBM. PT2385 is an oral HIF2a inhibitor with in vivo activity against GBM. Methods: A two-stage single-arm open-label phase II study of adults with first recurrent GBM following chemoradiation with measurable disease was conducted through the Adult Brain Tumor Consortium. PT2385 was administered at the phase II dose (800 mg b.i.d.). The primary outcome was objective radiographic response (CR+PR); secondary outcomes were safety and survival. Exploratory objectives included PK (day 15 Cmin), PD, and pH-weighted amine-CEST MRI to quantify tumor acidity at baseline and explore associations with drug response. Stage 1 enrolled 24 patients with early stoppage for ≤1 response. Results: Of the 24 patients, mean age was 61±11 years, median KPS 80, MGMT promoter methylated in 46%. PT2385 was well tolerated. Grade ≥3 drug-related AEs were hypoxia (n = 2), anemia (1), hyperglycemia (1), hyponatremia (2) and lymphopenia (2). No objective radiographic responses were observed; median PFS was 1.8 months (95%CI 1.6-3.1). Drug exposure varied widely (Table) and did not differ by corticosteroid use (p = 0.12), antiepileptics (p = 0.09), or sex (p = 0.37). Patients with high systemic exposure had significantly longer PFS (6.7 vs 1.8 months, 0.009). Non-enhancing infiltrative disease with high acidity gave rise to recurrence. Baseline acidity correlated significantly with treatment duration (R2= 0.49, p = 0.017). Conclusions: Drug exposure to PT2385 was variable. Signals of activity were observed in GBM patients with high systemic exposure and acidic (e.g. hypoxic) lesions on baseline imaging. A second-generation HIF2a inhibitor is being studied. Clinical trial information: NCT03216499. [Table: see text]

Brain metastases as a first site of recurrence in patients on chemotherapy with controlled systemic cancers: An increasingly urgent clinical scenario

e13590

Background: As the treatment of non-central nervous system (CNS) malignancies improves, brain metastases (BM) are occurring more often in patients with controlled primary disease. In a retrospective analysis of 1953 patients with BM, 44.7% had a controlled primary tumor at the time of BM diagnosis. Given that prognosis after BM remains dismal, it is necessary to identify groups who might benefit from improved delivery of initial systemic therapy across the blood brain barrier (BBB). Methods: A retrospective literature review was conducted to estimate the proportion of patients with non-small cell lung cancer (NSCLC), breast cancer, and melanoma treated with chemotherapy in whom BM was the initial site of recurrence. Only studies explicitly reporting CNS metastasis with controlled extra-cranial (EC) disease on chemotherapy or reporting the first site of recurrence after chemotherapy were included. Results: Four studies of advanced NSCLC reported an average of 23% of patients who developed BM as an initial site of recurrence. Breast cancer cases varied by subtype with a range of 4 - 19%. In four papers reporting HER-2 status, an average of 14% of patients treated with traztuzumab had CNS metastasis with controlled EC disease. In three papers assessing patients with metastatic melanoma on chemotherapy, 4 – 25% initially progressed in the CNS. Conclusions: Of the 1024 patients treated with chemotherapy and achieving controlled systemic disease in this retrospective review, first recurrence in the brain was common: 23% in NSCLC, 12% in breast cancer, and 12% in melanoma. While chemotherapy controlled non-CNS disease, concentrations of these drugs were clearly subtherapeutic in the CNS. Preventing BM in patients with NSCLC, breast cancer, and melanoma will require novel therapeutic approaches designed to facilitate drug entry through an intact BBB early in the treatment of the primary tumor. [Table: see text]

Updated phase I trial of anti-LAG-3 or anti-CD137 alone and in combination with anti-PD-1 in patients with recurrent GBM

2017

Background: Preclinical GBM data targeting the checkpoint molecules Lag-3 and CD137 have shown promising anti-tumor immune response with resultant improved survival when combined with anti-PD-1. Here we report our experience from a multi-arm safety study in patients with recurrent GBM treated with anti-Lag-3 and anti-CD137. Methods: The Adult Brain Tumor Consortium (ABTC) 1501 trial is a phase I, open label, multicenter, multi-arm dose-finding/safety study of anti-LAG-3 (BMS-986016) or anti-CD137 (BMS-663513) alone and in combination with anti-PD-1 in patients at first recurrence of GBM. The primary objective is to define MTD for the mono and combinational treatment. The major secondary objective is to explore for a signal in efficacy. The key inclusion criteria are adults, first recurrence of GBM following RT+TMZ, TLC≥1000/ul, KPS≥ 60%, stable corticosteroid regimen, measurable disease, and written informed consent. Sequential allocation was used for the treatment assignment at starting dose of 80mg for anti-LAG-3 and 8mg for anti-CD137. Anti-PD-1was given at a flat dose of 240 mg in the combination treatment arms. The 3+3 design is used for the dose finding with a target DLT rate < 33%. Results: to date 44 patients were enrolled into the trial with median age at 57, median KPS at 90. Median treatment cycle was 3 and 39% tumors were MGMT methylated. The highest safe dose for Anti-LAG-3 alone is 800 mg without a DLT. The safe dose for anti-CD137 alone arm is 8mg with 1 DLT, and 2 grade 3 elevated serum ALT at end of cycle 2. Combination arms of Anti-LAG-3 +anti-PD-1 (160 mg/240mg as the highest dose combination) had one DLT (hypertension) and no toxicities were seen in the combination arm of Anti-CD137+Anti-PD-1 (3 mg/240 mg). mOS was 14 months for anti-CD137 alone, 8 months for Anti-Lag-3, and 7 months for Anti-Lag-3 + Anti-PD-1. Correlative data will be discussed. Conclusions: The trial is ongoing. The RP2D is 800mg for anti-LAG-3 as a monotherapy and 8mg for anti-CD137. For the combination arms, 160 mg of Anti-LAG-3 and 240 mg of anti-PD-1 and 3 mg of anti-CD137 and 240 mg antiPD-1 were the RP2D. Clinical trial information: NCT02658981.

The role of postradiation temozolomide in patients with newly diagnosed MGMT methylated glioblastoma

e13530

Background: Standard therapy for patients with newly diagnosed glioblastoma (GBM) includes concurrent temozolomide (TMZ) and radiation (RT) followed by six monthly cycles of adjuvant TMZ. Although TMZ improves survival for MGMT methylated patients, it is unclear if this benefit is from the TMZ given with the radiation, the adjuvant TMZ, or if both are required. This retrospective study was designed to identify MGMT methylated patients who started treatment with near-normal functional status, completed concurrent RT+TMZ, but did not receive adjuvant TMZ to estimate if their survival was significantly less than expected. Methods: We reviewed charts from 190 adults diagnosed with GBM at Johns Hopkins Hospital from 2013 to 2015 recording their Karnofsky Performance Score (KPS), extent of resection, MGMT-methylation and IDH1 mutation status, and treatment records. We selected patients with MGMT-methylated GBM who received concurrent RT+TMZ without adjuvant TMZ for this study. Patients with a KPS < 70 or severe post-radiation complications were excluded. Results: Six patients met the selection criteria. They had a median age of 65 years, average KPS of 80, 2/6 had a gross total resection, and all were IDH1 wildtype. Their overall survival ranged from 17 to > 46 months. Conclusions: The overall survival of these patients who received no adjuvant TMZ is very similar to the median of 23 months reported in the literature for MGMT methylated patients who received adjuvant TMZ. This preliminary data suggests that a prospective study in MGMT methylated patients comparing concurrent RT+TMZ followed by either standard adjuvant TMZ or observation could be considered without placing patients in the experimental arm at excessive risk.[Table: see text]

Aquaporin-4 Expression Patterns in Glioblastoma Pre-Chemoradiation and at Time of Suspected Progression

There has been controversy about the presence and potential role of aquaporin-4 (AQP4) in glioblastoma (GBM). We analyzed tissue from 22 patients with newly-diagnosed GBM as well as matching tissue from 17 of these cases who underwent repeat resection for suspected recurrence and performed immunohistochemical analysis for AQP-4 expression. While some degree of AQP4 expression was detected in all 22 cases (39 samples), there was no clear relationship between staining pattern and disease status (active versus inactive GBM) between baseline and time of repeat biopsy. In addition, there was no clear relationship between AQP4 expression and degree of edema.

Phase I/II trial of vorinostat combined with temozolomide and radiation therapy for newly diagnosed glioblastoma: results of Alliance N0874/ABTC 02

Background

Vorinostat, a histone deacetylase (HDAC) inhibitor, has shown radiosensitizing properties in preclinical studies. This open-label, single-arm trial evaluated the maximum tolerated dose (MTD; phase I) and efficacy (phase II) of vorinostat combined with standard chemoradiation in newly diagnosed glioblastoma.

Methods

Patients received oral vorinostat (300 or 400 mg/day) on days 1-5 weekly during temozolomide chemoradiation. Following a 4- to 6-week rest, patients received up to 12 cycles of standard adjuvant temozolomide and vorinostat (400 mg/day) on days 1-7 and 15-21 of each 28-day cycle. Association between vorinostat response signatures and progression-free survival (PFS) and overall survival (OS) was assessed based on RNA sequencing of baseline tumor tissue.

Results

Phase I and phase II enrolled 15 and 107 patients, respectively. The combination therapy MTD was vorinostat 300 mg/day and temozolomide 75 mg/m2/day. Dose-limiting toxicities were grade 4 neutropenia and thrombocytopenia and grade 3 aspartate aminotransferase elevation, hyperglycemia, fatigue, and wound dehiscence. The primary efficacy endpoint in the phase II cohort, OS rate at 15 months, was 55.1% (median OS 16.1 mo), and consequently, the study did not meet its efficacy objective. Most common treatment-related grade 3/4 toxicities in the phase II component were lymphopenia (32.7%), thrombocytopenia (28.0%), and neutropenia (21.5%). RNA expression profiling of baseline tumors (N = 76) demonstrated that vorinostat resistance (sig-79) and sensitivity (sig-139) signatures had a reverse and positive association with OS/PFS, respectively.

Conclusions

Vorinostat combined with standard chemoradiation had acceptable tolerability in newly diagnosed glioblastoma. Although the primary efficacy endpoint was not met, vorinostat sensitivity and resistance signatures could facilitate patient selection in future trials.

Role of Temozolomide in the Treatment of Cancers Involving the Central Nervous System

Temozolomide has been available to oncologists for over 30 years. During this time, it has become an integral part of standard therapy in patients with high-grade gliomas. Given its ability to traverse the blood-brain barrier, temozolomide has also been evaluated in other cancers that involve the central nervous system (CNS). We review its role in the management of patients with primary brain tumors, brain metastases, leptomeningeal carcinomatosis, and other selected CNS cancers. There is strong evidence that temozolomide is effective in patients with high-grade astrocytomas and oligodendrogliomas. Modest evidence supports its activity in primary CNS lymphomas and aggressive pituitary adenomas. Temozolomide, however, has minimal efficacy in a wide variety of systemic cancers. Given that concentrations of temozolomide in the CNS are only 20% of those in the blood, it is not surprising that it is generally inactive in patients with CNS metastases from solid tumors.

The consistency of neuropathological diagnoses in patients undergoing surgery for suspected recurrence of glioblastoma

Purpose

Clinical factors and neuro-imaging in patients with glioblastoma who appear to progress following standard chemoradiation are unable to reliably distinguish tumor progression from pseudo-progression. As a result, surgery is commonly recommended to establish a final diagnosis. However, studies evaluating the pathologists’ agreement on pathologic diagnoses in this setting have not been previously evaluated.

Methods

A hypothetical clinical history coupled with images of histological sections from 13 patients with glioblastoma who underwent diagnostic surgery for suspected early recurrence were sent to 101 pathologists from 50 NCI-designated Cancer Centers. Pathologists were asked to provide a final diagnosis (active tumor, treatment effect, or unable to classify) and to report on percent active tumor, treatment effect, and degree of cellularity and degree of mitotic activity.

Results

Forty-eight pathologists (48%) from 30 centers responded. In three cases > 75% of pathologists diagnosed active tumor. In two cases > 75% diagnosed treatment effect. However, in the remaining eight cases the disparity in diagnoses was striking (maximum agreement on final diagnosis ranged from 36 to 68%). Overall, only marginal agreement was observed in the overall assessment of disease status [kappa score 0.228 (95% CI 0.22–0.24)].

Conclusions

Confidence in any clinical diagnostic assay requires that very similar results are obtained from identical specimens evaluated by sophisticated clinicians and institutions. The findings of this study illustrate that the diagnostic agreement between different cases of repeat resection for suspected recurrent glioblastoma can be variable. This raises concerns as pathological diagnoses are critical in directing standard and experimental care in this setting.

Electronic supplementary material

The online version of this article (10.1007/s11060-018-03037-3) contains supplementary material, which is available to authorized users.

Phase II Study of Iniparib with Concurrent Chemoradiation in Patients with Newly Diagnosed Glioblastoma

PURPOSE

Iniparib is a purported prodrug causing cell death through intracellular conversion to nitro radical ions. We assessed the efficacy and safety of iniparib with standard radiotherapy and temozolomide in patients with newly diagnosed glioblastoma (GBM).

PATIENTS AND METHODS

Adults meeting eligibility criteria were enrolled in this prospective, single-arm, open-label multi- institution phase II trial with median overall survival (mOS) compared with a historical control as the primary objective. A safety run-in component of radiotherapy + temozolomide + iniparib (n = 5) was followed by an efficacy study (n = 76) with the recommended phase II doses of iniparib (8.0 mg/kg i.v. twice/week with radiotherapy + daily temozolomide followed by 8.6 mg/kg i.v. twice/week with 5/28-day temozolomide).

RESULTS

The median age of the 81 evaluable participants was 58 years (63% male). Baseline KPS was ≥ 80% in 87% of participants. The mOS was 22 months [95% confidence interval (CI), 17-24] and the HR was 0.44 (95% CI, 0.35-0.55) per-person-year of follow-up. The 2- and 3-year survival rates were 38% and 25%, respectively. Treatment-related grade 3 adverse events (AEs) occurred in 27% of patients; 9 patients had AEs requiring drug discontinuation including infusion-related reaction, rash, gastritis, increased liver enzymes, and thrombocytopenia.

CONCLUSIONS

Iniparib is well tolerated with radiotherapy and temozolomide in patients with newly diagnosed GBM at up to 17.2 mg/kg weekly. The primary objective of improved mOS compared with a historical control was met, indicating potential antitumor activity of iniparib in this setting. Dosing optimization (frequency and sequence) is needed prior to additional efficacy studies.

Severe Treatment-Related Lymphopenia in Patients with Newly Diagnosed Rectal Cancer

BACKGROUND

Although treatment-related lymphopenia (TRL) is common in many cancers no data exists in rectal cancer.

METHODS

Serial lymphocyte counts were analyzed retrospectively in patients with newly diagnosed rectal cancer, serial blood counts, and complete records at Johns Hopkins Hospital.

RESULTS

Fifty-seven patients with normal pretreatment lymphocyte counts were studied. Two months after beginning chemoradiation, 35% of these patients developed grade III-IV lymphopenia [median lymphocyte counts fell from 1590 to 490 cell/mm³ (p < 0.001)] which persisted throughout one year of observation.

CONCLUSION

Severe and prolonged TRL is common in rectal cancer. Further studies are required to determine TRL's relationship to survival.

Systemic depletion of lymphocytes following focal radiation to the brain in a murine model

Severe radiation-related lymphopenia is common and associated with decreased survival in patients with several solid tumors. As the mechanisms underlying systemic lymphopenia are poorly understood, we developed an animal model to study the effects of brain radiation on lymphocytes and cytokines. C57 BL/6 and BALB/c mice received focal brain irradiation (4 Gy x 10 fractions or 2 Gy x 30 fractions). Weekly total lymphocyte counts (TLC), lymphocyte subsets and cytokines in blood and lymph nodes were measured. Non-irradiated lymph nodes were collected and examined before, during, and after radiation. We found that systemic TLC decreased rapidly irrespective of mouse strain or radiation schedule. 4 Gy x 10 resulted in a 42% and 75% & 70% and 49% TLC reduction in C57 BL/6 and BALB/c mice respectively. 2 Gy x 30 caused a 70% / 49% decrease in TLC in C57 BL/6 and BALB/c. Similar trends were seen for total T cells, CD4⁺, regulatory T and CD8⁺ cells. Changes in lymph node architecture and cellular composition correlated with the development of systemic lymphopenia. Three weeks after radiation, TLC returned to 60-80% of baseline, preceded by increased IL-7 levels in the lymph nodes. Focal brain radiation in mice results in significant systemic lymphodepletion.

Timed sequential therapy of the selective T-type calcium channel blocker mibefradil and temozolomide in patients with recurrent high-grade gliomas

Background

Mibefradil (MIB), previously approved for treatment of hypertension, is a selective T-type calcium channel blocker with preclinical activity in high-grade gliomas (HGGs). To exploit its presumed mechanism of impacting cell cycle activity (G1 arrest), we designed a phase I study to determine safety and the maximum tolerated dose (MTD) of MIB when given sequentially with temozolomide (TMZ) in recurrent (r)HGG.

Methods

Adult patients with rHGG ≥3 months from TMZ for initial therapy received MIB in 4 daily doses (q.i.d.) for 7 days followed by standard TMZ at 150-200 mg/m2 for 5 days per 28-day cycle. MIB dose escalation followed a modified 3 + 3 design, with an extension cohort of 10 patients at MTD who underwent 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) PET imaging, to image proliferation before and after 7 days of MIB.

Results

Twenty-seven patients were enrolled (20 World Health Organization grade IV, 7 grade III; median age 50 y; median KPS 90). The MTD of MIB was 87.5 mg p.o. q.i.d. Dose-limiting toxicities were elevation of alanine aminotransferase/aspartate aminotransferase (grade 3) and sinus bradycardia. The steady-state maximum plasma concentration of MIB at the MTD was 1693 ± 287 ng/mL (mean ± SD). 18F-FLT PET imaging showed a significant decline in standardized uptake value (SUV) signal in 2 of 10 patients after 7 days of treatment with MIB.

Conclusions

MIB followed by TMZ was well tolerated in rHGG patients at the MTD. The lack of toxicity and presence of some responses in this selected patient population suggest that this regimen warrants further investigation.

Kinetics and dosimetric predictors of acute radiation-induced lymphopenia in pancreatic cancer

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Background: Radiation (RT) induced lymphopenia (RIL) is an adverse prognostic factor in pancreatic cancer (PC) and is likely due to the irradiation of lymphocytes in the RT field. The goal of this study was to identify dosimetric predictors for high rates of absolute lymphocyte count (ALC) loss during RT for PC. Methods: This was a retrospective study of 34 PC patients in an institutional database who had received concurrent 5-FU or gemcitabine-based chemoradiation (50-54 Gy) and had ≥ 3 ALCs measured during RT. Baseline ALC was normal (>1000 cells/uL) in 28/34 (82%) and grade 3-4 RIL occurred in 24/34 (71%). ALC was plotted against fraction # and a best-fit line for each patient was created to determine per-fraction loss in ALC (PFLAC). Linear regression was used to correlate PFLAC with dosimetric parameters including mean dose to gut, liver, kidney, spleen, and cisterna chyli, as well as estimated dose to immune cells (EDIC), which calculates dose to immune cells according to the % of body lymphocytes contained in each organ. Results: All patients exhibited exponential loss in ALC during RT. Mean PFLAC was 6.8% (range 1.7-13.4); fraction # was strongly correlated with ALC (mean R2 = 0.89). Patients with >/= grade 3 lymphopenia had a significantly higher PFLAC than those with grade 0 - 2 lymphopenia (mean daily loss 7.8% in Gr 3-4 vs. 4.8% in Gr 0-2, p = 0.001; independent sample T test). Field size was not correlated with PFLAC for high (> 1 Gy) or low (< 0.5 Gy) isodose volumes. Mean whole body (r = 0.59, p < 0.001), bowel (r = 0.39, p = 0.012), liver (r = 0.42, p = 0.007), and cisterna chyli (r = 0.583, p = 0.004) doses were moderately correlated with PFLAC; mean kidney (r = 0.22, p = 0.11) and spleen (r = 0.26, p = 0.06) doses were weakly correlated with PFLAC. EDIC was more strongly correlated with PFLAC than any individual organ mean dose (r = 0.69, p < 0.001). Conclusions: Patients undergoing RT for PC experience a predictable RIL characterized by an exponential loss of lymphocytes per day. PFLAC is a useful method of characterizing RIL and facilitates evaluation of dosimetric predictors of RIL. We identified dose to cisterna chyli as a significant contributor to RIL in PC; however, EDIC has a stronger correlation with RIL severity than any single organ dose.

The effect of an adenosine A2A agonist on intra-tumoral concentrations of temozolomide in patients with recurrent glioblastoma

Background

The blood–brain barrier (BBB) severely limits the entry of systemically administered drugs including chemotherapy to the brain. In rodents, regadenoson activation of adenosine A_2A receptors causes transient BBB disruption and increased drug concentrations in normal brain. This study was conducted to evaluate if activation of A_2A receptors would increase intra-tumoral temozolomide concentrations in patients with glioblastoma.

Methods

Patients scheduled for a clinically indicated surgery for recurrent glioblastoma were eligible. Microdialysis catheters (MDC) were placed intraoperatively, and the positions were documented radiographically. On post-operative day #1, patients received oral temozolomide (150 mg/m²). On day #2, 60 min after oral temozolomide, patients received one intravenous dose of regadenoson (0.4 mg). Blood and MDC samples were collected to determine temozolomide concentrations.

Results

Six patients were enrolled. Five patients had no complications from the MDC placement or regadenoson and had successful collection of blood and dialysate samples. The mean plasma AUC was 16.4 ± 1.4 h µg/ml for temozolomide alone and 16.6 ± 2.87 h µg/ml with addition of regadenoson. The mean dialysate AUC was 2.9 ± 1.2 h µg/ml with temozolomide alone and 3.0 ± 1.7 h µg/ml with regadenoson. The mean brain:plasma AUC ratio was 18.0 ± 7.8 and 19.1 ± 10.7% for temozolomide alone and with regadenoson respectively. Peak concentration and T_max in brain were not significantly different.

Conclusions

Although previously shown to be efficacious in rodents to increase varied size agents to cross the BBB, our data suggest that regadenoson does not increase temozolomide concentrations in brain. Further studies exploring alternative doses and schedules are needed; as transiently disrupting the BBB to facilitate drug entry is of critical importance in neuro-oncology.

Electronic supplementary material

The online version of this article (10.1186/s12987-017-0088-8) contains supplementary material, which is available to authorized users.

Relationships between lymphocyte counts and treatment-related toxicities and clinical responses in patients with solid tumors treated with PD-1 checkpoint inhibitors

The relationships between absolute lymphocyte counts (ALC), drug- related toxicities, and clinical responses remain unclear in cancer patients treated with PD-1 (programmed cell death 1) inhibitors. We performed a retrospective review of 167 adult solid tumor patients treated with nivolumab or pembrolizumab at a single institution between January 2015 and November 2016. Patients with an ALC >2000 at baseline had an increased risk of irAE (OR 1.996, p<0.05) on multivariate analysis. In a multivariate proportional hazards model, a shorter time to progression was noted in patients who were lymphopenic at baseline (HR 1.45 (p<0.05)) and at three months (HR 2.01 (p<0.05)). Patients with baseline lymphopenia and persistent lymphopenia at month 3 had a shorter time to progression compared to those who had baseline lymphopenia but recovered with ALC > 1000 at 3 months (HR 2.76, p<0.05). Prior radiation therapy was the characteristic most strongly associated with lymphopenia at 3 months (OR 2.24, p<0.001). These data suggest that patients with higher baseline lymphocyte counts have a greater risk for irAE, whereas patients with lymphopenia at baseline and persistent lymphopenia while on therapy have a shorter time to progression on these agents. These associations require further validation in additional patient cohorts.