Phase 1/2 trial of avelumab combined with utomilumab (4-1BB agonist), PF-04518600 (OX40 agonist), or radiotherapy in patients with advanced gynecologic malignancies

BACKGROUND

Immune checkpoint blockade has shown mixed results in advanced/recurrent gynecologic malignancies. Efficacy may be improved through costimulation with OX40 and 4-1BB agonists. The authors sought to evaluate the safety and efficacy of avelumab combined with utomilumab (a 4-1BB agonist), PF-04518600 (an OX40 agonist), and radiotherapy in patients with recurrent gynecologic malignancies.

METHODS

The primary end point in this six-arm, phase 1/2 trial was safety of the combination regimens. Secondary end points included the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors and immune-related Response Evaluation Criteria in Solid Tumors, the disease control rate (DCR), the duration of response, progression-free survival, and overall survival.

RESULTS

Forty patients were included (35% with cervical cancer, 30% with endometrial cancer, and 35% with ovarian cancer). Most patients (n = 33; 83%) were enrolled in arms A-C (no radiation). Among 35 patients who were evaluable for efficacy, the ORR was 2.9%, and the DCR was 37.1%, with a median duration of stable disease of 5.4 months (interquartile range, 4.1-7.3 months). Patients with cervical cancer in arm A (avelumab and utomilumab; n = 9 evaluable patients) achieved an ORR of 11% and a DCR of 78%. The median progression-free survival was 2.1 months (95% CI, 1.8-3.5 months), and overall survival was 9.4 months (95% CI, 5.6-11.9 months). No dose-limiting toxicities or grade 3-5 immune-related adverse events were observed.

CONCLUSIONS

The findings from this trial highlight that, in heavily pretreated patients with gynecologic cancer, even multidrug regimens targeting multiple immunologic pathways, although safe, did not produce significant responses. A DCR of 78% in patients with cervical cancer who received avelumab and utomilumab indicates that further research on this combination in select patients may be warranted.

T-cell receptor beta variable gene polymorphism predicts immune-related adverse events during checkpoint blockade immunotherapy

BACKGROUND

Immune checkpoint inhibitors have revolutionized cancer treatment. However, they are associated with a unique spectrum of side effects, called immune-related adverse events (irAEs), which can cause significant morbidity and quickly progress to severe or life-threatening events if not treated promptly. Identifying predictive biomarkers for irAEs before immunotherapy initiation is therefore a critical area of research. Polymorphisms within the T-cell receptor beta (TCRB) variable (TRBV) gene have been implicated in autoimmune disease and may be mechanistically linked to irAEs. However, the repetitive nature of the TCRB locus and incomplete genome assembly has hampered the evaluation of TRBV polymorphisms in the past.

PATIENTS AND METHODS

We used a novel method for long-amplicon next generation sequencing of rearranged TCRB chains from peripheral blood total RNA to evaluate the link between TRBV polymorphisms and irAEs in patients treated with immunotherapy for cancer. We employed multiplex PCR to create amplicons spanning the three beta chain complementarity-determining regions (CDR) regions to enable detection of polymorphism within the germline-encoded framework and CDR1 and CDR2 regions in addition to CDR3 profiling. Resultant amplicons were sequenced via the Ion Torrent and TRBV allele profiles constructed for each individual was correlated with irAE annotations to identify haplotypes associated with severe irAEs (≥ grade 3).

RESULTS

Our study included 81 patients who had irAEs when treated with immunotherapy for cancer. By using principal component analysis of the 81 TRBV allele profiles followed by k-means clustering, we identified six major TRBV haplotypes. Strikingly, we found that one-third of this cohort possessed a TRBV allele haplotype that appeared to be protective against severe irAEs.

CONCLUSION

The data suggest that long-amplicon TCRB repertoire sequencing can potentially identify TRBV haplotype groups that correlate with the risk of severe irAEs. Germline-encoded TRBV polymorphisms may serve as a predictive biomarker of severe irAEs.

Phase 2 study of pembrolizumab in patients with advanced rare cancers

Background

Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers.

Methods

In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR).

Results

A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14). CBR, defined as the percentage of patients with an OR or stable disease ≥4 months, was 38% (n=42). Treatment was ongoing in 11 of 15 patients with OR at last follow-up. In the cohort with squamous cell carcinoma (SCC) of the skin, the NPR at 27 weeks was 36%, ORR 31%, and CBR 38%. In patients with adrenocortical carcinoma (ACC), NPR at 27 weeks was 31%, ORR 15%, and CBR 54%. In the patients with carcinoma of unknown primary (CUP), NPR at 27 weeks was 33%, ORR 23%, and CBR 54%. In the paraganglioma–pheochromocytoma cohort, NPR at 27 weeks was 43%, ORR 0%, and CBR 75%. Treatment-related adverse events (TRAEs) occurred in 66 of 127 (52%) patients, and 12 (9%) had grade ≥3 TRAEs. The most common TRAEs were fatigue (n=25) and rash (n=17). There were six deaths, all of which were unrelated to the study drug.

Conclusions

The favorable toxicity profile and antitumor activity seen in patients with SCC of skin, ACC, CUP, and paraganglioma–pheochromocytoma supports further evaluation of pembrolizumab in this patient population.

Trial registration number

NCT02721732

Decrease in tumor content assessed in biopsies is associated with improved treatment outcome response to pembrolizumab in patients with rare tumors

BACKGROUND

Decreased tumor content (TC) in resection specimens after neoadjuvant therapy is used to predict prognosis. We investigated whether TC assessed in biopsy specimens or the shift in TC from baseline to on-treatment can be used accordingly to predict response in patients with rare tumors who were treated with pembrolizumab.

METHODS

A total of 57 tumors (represented by 173 baseline and 179 on-treatment biopsies) from 57 patients with rare tumors participating in an ongoing phase II clinical trial of pembrolizumab were evaluated. TC was estimated on H&E-stained slides and tumors were dichotomized into low and high TC according to a cut-off of 10%. Necrosis, proliferative fibrosis (PF) and normal tissue were assessed in on-treatment biopsies. TC at baseline and on-treatment, as well as the shift in TC from baseline to on-treatment, was correlated with clinical response defined according to Response Evaluation Criteria in Solid Tumors.

RESULTS

A decrease in TC was seen in 14% (n=8); no change in TC was seen in 75% (n=43); and an increase in TC from baseline to on-treatment was seen in 11% (n=6). Objective response was significantly associated with decrease in TC from baseline to on-treatment (38%, 3/8) compared with no change/increase in TC (6%, 3/49) (p=0.031). Patients with a decrease in TC had a significantly increased time to progression (TTP) (75% probability) compared with patients with an increase (20% probability) or no change in TC (19% probability) (p=0.0042). Low TC was seen in 23% (13/57) of the tumors at baseline and in 26% (15/57) on-treatment. High TC was seen in 77% (44/57) of tumors at baseline and in 74% (42/57) on-treatment. No significant associations with response were seen for necrosis, PF or normal tissue in on-treatment biopsies.

CONCLUSION

Patients with a decrease in TC from baseline to on-treatment had a significant improvement in objective response and a longer TTP. Our data suggest that the shift in TC might be used to predict response to pembrolizumab in rare tumors. However, further investigations in larger cohorts are needed to determine the clinical value of TC, the shift in TC and the cut-off of 10% assessed in biopsies.

TRIAL REGISTRATION NUMBER

NCT02721732.

Efficacy of pembrolizumab in patients with pituitary carcinoma: report of four cases from a phase II study

Pituitary carcinoma is an aggressive tumor characterized by metastatic spread beyond the sellar region. Symptoms can be debilitating due to hormonal excess and survival is poor. Pituitary carcinomas recur despite conventional multimodality treatments. Given the recent advances in the use of immune checkpoint inhibitors (CPIs) to treat various solid cancers, there has been interest in exploring the role of immunotherapy for treating aggressive, refractory pituitary tumors. We treated 4 patients with pituitary carcinoma with pembrolizumab as part of a phase II clinical trial. Two patients (patients 1 and 2) with functioning corticotroph pituitary carcinomas (refractory to surgery, radiotherapy and chemotherapy) had partial radiographic (60% and 32% per Immune-Related Response Evaluation Criteria In Solid Tumors, respectively) and hormonal responses. Patient 1’s response continues 42 months after initiation of pembrolizumab and his tumor tissue obtained after treatment with temozolomide demonstrated a hypermutator phenotype with MSH2 and MSH6 gene mutations. Patient 2’s tumor after exposure to temozolomide was not sampled, but prior somatic mutational testing was negative. One patient with a non-functioning corticotroph tumor (patient 3) had a best response of stable disease for 4 months. One patient with a prolactin-secreting carcinoma (patient 4) had progressive disease. The latter 2 patients’ tumors did not demonstrate a hypermutator phenotype after treatment with temozolomide. Programmed death-ligand 1 staining was negative in all tumors. We report 2 cases of corticotroph pituitary carcinoma responsive to pembrolizumab after prior exposure to alkylating agents. The role of CPIs in treating patients with pituitary carcinoma, the relationship between tumor subtype and response to immunotherapy and mechanisms of hypermutation in this orphan disease require further study. Trial registration number: NCT02721732.

CTIM-30. EFFICACY OF PEMBROLIZUMAB IN PATIENTS WITH PITUITARY CARCINOMA: RESULTS FROM A PHASE II STUDY

Pituitary carcinoma is an aggressive tumor characterized by metastatic spread beyond the sellar region that leads to debilitating symptoms and poor survival. Pituitary carcinomas recur despite conventional multimodality treatments. Given the recent advances in the use of immune checkpoint inhibitors (CPIs) to treat various solid cancers, there is interest in exploring the role of immunotherapy for treating aggressive, refractory pituitary tumors. We treated four pituitary carcinoma patients with pembrolizumab as part of a phase II clinical trial (NCT02721732). Here, we present their clinical course and outcomes and correlate responses with available molecular data: hypermutation status, PD-L1 staining, tumor-infiltrating lymphocyte score, microsatellite status and tumor mutational burden. Patients 1 and 2, with heavily pretreated, refractory corticotroph pituitary carcinoma, had partial radiographic (60% and 32% per irRECIST, respectively) and hormonal responses. Patient 1’s response continues 42 months after initiation of pembrolizumab and his baseline tumor tissue obtained after treatment with temozolomide demonstrated a hypermutator phenotype with MSH2 and MSH6 gene mutations. Patient 2’s tumor was not sampled after exposure to temozolomide, but prior somatic mutational testing was negative. Patient 3 (non-functioning corticotroph tumor) had a best response of stable disease for four months. Patient 4 (prolactin-secreting carcinoma) had progressive disease. The latter two patients’ tumors did not demonstrate a hypermutator phenotype after treatment with temozolomide. PD-L1 staining was negative in all tumors. TIL score was 2 in Patients 1 and 4, negative in Patient 3 and not available in Patient 2. All patients tolerated the treatment well with mild adverse events. Our study generates the hypothesis that an alkylating agent-induced hypermutator phenotype may be an indicator of response to CPIs in pituitary carcinomas. The role of CPI in treating patients with pituitary carcinoma and mechanisms of hypermutation in this population require further study.

Abstract A44: No tumor or very small tumor burden in on-treatment biopsies is significantly associated with response to Pembrolizumab

Background: In phase I clinical trials, baseline and on-treatment biopsies are increasingly performed to investigate biomarkers correlating, e.g., with therapy response. Prior to use these biopsies for expensive analysis, quality control (QC) is performed regarding, e.g., morphology, tumor content. However, studies to correlate the results obtained from QC evaluation with clinical outcomes are lacking. The purpose of this study was to determine if data from the QC process correlate with therapy response.

Method: We investigated 64 baseline and 50 on-treatment (C1D15-21) biopsies from 67 patients participating in an ongoing phase I clinical trial receiving pembrolizumab for their rare tumors such as e.g. adrenocortical carcinoma, angiosarcoma, alveolar rhabdomyosarcoma, carcinoma of unknown primary, epithelioid hemangioendothelioma, malignant neoplasm of tunica vaginalis, paraganglioma, penile carcinoma, pituitary tumor, renal medullary carcinoma, teratoma, and others. Baseline and the on-treatment biopsies were taken in >90% from the same amenable tumor lesion. Matched biopsies were available in n= 48 (71.64%) and data on response was available for 54 (80.60%) patients. From all biopsies the tumor content was estimated by a pathologist on an H&E slide. Low tumor burden was defined as 0-10% tumor in the biopsy. If more than one biopsy was available, the average tumor content was calculated and used for analysis. Response was defined as stable disease or partial response.

Results: The average tumor content in all biopsies was 39%, 38% baseline and 39% on-treatment. No tumor was detected in 15 (13%) of all biopsies, in 7 baseline (11%) and 8 on-treatment biopsies (16%). Low tumor burden was detected in 29 (25%) of all biopsies, in 17 baseline (27%) and in 12 on-treatment biopsies (24%). In 71% (5/7) of baseline biopsies and in 50% (4/8) of on-treatment biopsies with no tumor, fibrosis or necrosis was present. In 88% (15/17) of baseline biopsies and 67% (8/12) of on-treatment biopsies with low tumor burden fibrosis or necrosis was present. Thirty percent (7/23) of patients with response had no tumor in their on-treatment biopsies. All non-responders had tumor in their on-treatment biopsy. Forty three (10/23) patients with a low tumor burden in their on-treatment biopsies showed response compared to 5% (1/21) of non-responders. Hence, no tumor (0%) or low tumor burden (0-10%) in on-treatment biopsies was significantly associated with response (p=0.006 and p=0.003).

Conclusion: Results obtained from the QC of clinical trial biopsies provide valuable information on tissue suitability for further analysis. In addition, we showed that an on-treatment biopsy with no tumor or very little tumor burden may predict partial or stable disease. Further studies to validate the role of tumor content in on-treatment biopsies in predicting response are warranted.

Citation Format: Mingxuan Xu, Fengying Ouyang, Anas Alshawa, Joud Hajjar, Lilibeth Castillo, Hung Le, Ravi Murthy, Aung Naing, Coya Tapia. No tumor or very small tumor burden in on-treatment biopsies is significantly associated with response to Pembrolizumab [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A44.

Incidence of immune-related adverse events and its association with treatment outcomes: the MD Anderson Cancer Center experience

Background Immunotherapy is emerging as the cornerstone for treatment of patients with advanced cancer, but significant toxicity (immune-related adverse events [irAEs]) associated with unbridled T cell activity remains a concern. Patients and methods A retrospective review of the electronic medical records of 290 patients with advanced cancer treated on an immunotherapy-based clinical trial in the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center between February 2010 and September 2015 was performed. Clinical and laboratory parameters were collected to determine the incidence of irAEs, risk factors, and their association with treatment outcomes. Results Ninety eight of 290 patients (34%) experienced any grade irAEs. Among the 15 (5.2%) patients with grade ≥ 3 irAEs, the most common irAEs were dermatitis and enterocolitis. Although 80% of the patients with grade ≥ 3 irAEs required systemic corticosteroids, all the 15 patients recovered from the irAEs. On re-challenge, 4 of the 5 patients who had received systemic corticosteroids for irAE continued to respond. There were no irAE-related deaths. Importantly, patients with grade ≥ 3 irAEs had improved overall response rate (25 vs. 6%; p = 0.039) and longer median time to progression (30 weeks vs. 10 weeks; p = 0.0040) when compared to those without grade ≥ 3 irAEs. Conclusion Incidence of irAEs with immunotherapeutic agents indicates an active immune status, suggestive of potential clinical benefit to the patient. Further validation of this association in a large prospective study is warranted.

Hepatotoxicity in advanced cancer patients receiving immune-based cancer treatment

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Background: Immune-based cancer treatment (IBCT) is increasingly used to treat a variety of cancers. Despite the promising results, adverse events such as dermatitis, colitis, and hepatitis remain a concern. Hepatitis is usually mild but may be severe, requiring modification or cessation of treatment. Here, we describe several cases of immune-mediated hepatitis. Methods: We identified patients enrolled in clinical trials using IBCT through the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center, between January 2010 and July 2015. Charts were reviewed for mention of “autoimmune hepatitis”, “hepatitis” or abnormal transaminases, all of which were attributed to IBCT by the treating physician. Hepatotoxicity was graded based on CTCAE v4.0. Results: We identified 12 cases of immune-related hepatotoxicity out of 290 patients. Three patients (1.03%) had grade 3 elevation of transaminases, designated as “autoimmune hepatitis.” Each required systemic steroids and transaminases returned to baseline within a month. IBCT was temporarily held in 2 cases and was permanently discontinued in the third due to grade 4 myositis rather than hepatitis. One patient (0.3%) had grade 2, and eight patients (2.8%) had grade 1 transaminases elevations that were possibly attributable to immunotherapy, but which resolved spontaneously without alteration in treatment. Other significant reported immune-related toxicities ≥ grade 3 were: dermatitis (n = 4), enterocolitis (n = 3), myasthenia gravis (n = 2), myositis (n = 2), pneumonitis, pleuritis, and pancreatitis (n = 1 each). Conclusions: 1.03% of patients experienced grade 3 elevation of transaminases that were attributable to immune therapy. Hepatic adverse events related to immunotherapy in our study were manageable. Further studies are needed to develop biomarkers to identify patients at risk to develop such toxicities. [Table: see text]

Radiomics to predict immunotherapy-induced pneumonitis: proof of concept

We present the first reported work that explores the potential of radiomics to predict patients who are at risk for developing immunotherapy-induced pneumonitis. Despite promising results with immunotherapies, immune-related adverse events (irAEs) are challenging. Although less common, pneumonitis is a potentially fatal irAE. Thus, early detection is critical for improving treatment outcomes; an urgent need to identify biomarkers that predict patients at risk for pneumonitis exists. Radiomics, an emerging field, is the automated extraction of high fidelity, high-dimensional imaging features from standard medical images and allows for comprehensive visualization and characterization of the tissue of interest and corresponding microenvironment. In this pilot study, we sought to determine whether radiomics has the potential to predict development of pneumonitis. We performed radiomic analyses using baseline chest computed tomography images of patients who did (N = 2) and did not (N = 30) develop immunotherapy-induced pneumonitis. We extracted 1860 radiomic features in each patient. Maximum relevance and minimum redundancy feature selection method, anomaly detection algorithm, and leave-one-out cross-validation identified radiomic features that were significantly different and predicted subsequent immunotherapy-induced pneumonitis (accuracy, 100% [p = 0.0033]). This study suggests that radiomic features can classify and predict those patients at baseline who will subsequently develop immunotherapy-induced pneumonitis, further enabling risk-stratification that will ultimately lead to better treatment outcomes.

Immuno-oncology and the elderly: A comparative analysis of participation and toxicities of senior adults aged 65 years and above vs mid age and adolescent/young adult patients on immunotherapy-based phase I clinical trials

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Background: Senior adults ≥ 65 yrs remain underrepresented in early phase clinical trials in particular trials with novel immunotherapies. One general limitation to enrollment is the concern for immune-related toxicities in the context of older age and comorbidities. We analyzed the enrollment and incidence of toxicities of seniors in comparison to mid age and adolescent/young adult (AYA) pts enrolled in phase 1 immunotherapy trials. Methods: We identified 422 consecutive pts w advanced cancer treated on immunotherapy-based phase I trials bw 04/2009-09/2015. We divided pts into 3 cohorts based on age at start of trial (AYA 15-39y, mid age 40-64y, seniors 65y+) and collected pt/disease characteristics and immune-related adverse events (irAE) including endocrinopathies, diarrhea/colitis, pneumonitis, constitutional (eg fatigue, fever, anorexia), myalgia, and dermatitis. Results: Of 422 patients treated, 116 were seniors (27%, median 70y), 50 AYA (12%, median 30y), 256 mid age (61%, median 56y). Most common cancers were GI (n = 108, 26%), thoracic/head/neck (n = 84, 20%), GU (n = 54, 13%), and GYN (n = 47, 11%). Median PFS was comparable in all 3 cohorts (2.4m seniors, 2.1m AYA, 2.1m mid age). The incidence of irAE was higher in elderly than mid age or AYA (low grade [G1/2] 49% vs 34% vs 34%, p 0.02; high grade [G3/4] 19% vs 11% vs 12%. p 0.14). When comparing irAE rates of seniors to AYA and mid age pts, the odds ratio of high grade events was 1.81 (95% CI 1.01, 3.24; p 0.05) and low grade events was 1.85 (95% CI 1.20, 2.85; p 0.0055). Most common G1/2 irAE among all cohorts was fatigue (n = 76, 18%), dermatitis (n = 59, 14%), fever (n = 29, 7%) and anorexia (n = 28, 7%) with seniors having a greater incidence of low grade fatigue (25% vs 15%, OR 1.84, 95% CI 1.09, 3.10, p 0.025). Conclusions: Senior adults accounted for < 1/3 of pts on immunotherapy-based phase I trials. When compared to mid age and AYA pts, seniors had a higher likelihood of experiencing a toxicity. Early phase immunotherapy trials may be an option for older adults but with a particular vigilance for adverse events in this population.

Adverse Events in Cancer Immunotherapy

Cancer immunotherapy has resulted in durable responses in patients with metastatic disease, unseen with traditional chemotherapy. Several therapies have been approved by the Food and Drug Administration for the treatment of various cancers, including: immune checkpoint inhibitors, cytokines - interleukin 2 (IL-2) and interferon alpha (IFN), and the cancer vaccine sipuleucel-T. These therapies upregulate the immune system to enhance antitumor responses. As a consequence, they can cause inflammatory and immune-related adverse events that can affect one or more organs, can be serious, and on occasion lifethreatening. The management of these adverse events is complex, and requires a multidisciplinary approach involving not only oncologists, but also other internal medicine specialists, to ensure prompt diagnosis and optimal management of these complications.