Osteosarcoma in Pediatric and Adult Populations: Are Adults Just Big Kids?

Malignant bone tumors are commonly classified as pediatric or adolescent malignancies, and clinical trials for these diseases have generally focused on these populations. Of primary bone cancers, osteosarcoma is among the most common. Osteosarcoma has a bimodal age distribution, with the first peak occurring in patients from 10 to 14 years old, and the second peak occurring in patients older than 65, with about 25% of cases occurring in adults between 20 and 59 years old. Notably, adult osteosarcoma patients have worse outcomes than their pediatric counterparts. It remains unclear whether age itself is a poor prognostic factor, or if inherent differences in tumor biology exist between age groups. Despite these unknowns, current treatment strategies for adults are largely extrapolated from pediatric studies since the majority of clinical trials for osteosarcoma treatments are based on younger patient populations. In light of the different prognoses observed in pediatric and adult osteosarcoma, we summarize the current understanding of the molecular etiology of osteosarcoma and how it may differ between age groups, hypothesizing why adult patients have worse outcomes compared to children.

Intraosseous Spindle Cell Rhabdomyosarcoma with MEIS1::NCOA2 Fusion - Case Report with Substantial Clinical Follow-up and Review of the Literature

Spindle cell/sclerosing rhabdomyosarcoma (SSRMS) is a clinicopathologically and molecularly heterogeneous disease. Gene fusions have been identified in intraosseous SSRMS, consisting predominantly of EWSR1/FUS::TFCP2 and MEIS1::NCOA2. The former often follow an aggressive clinical course; there is limited clinical follow-up available for the latter. We report here a new case of the very rare intraosseous SSRMS with MEIS1::NCOA2 gene fusion and include the detailed treatment course and 52 months of clinical follow-up. SSRMS with MEIS1::NCOA2 gene fusion appears biologically distinct from other intraosseous SSRMS, following a course characterized by local recurrence with rare reports of metastasis to date.

Abstract 554: The role of Mycobacterium w as a novel treatment for osteosarcoma

Osteosarcoma (OS) is the most common malignant primary tumor of bone and occurs in adolescents and young adults as well as in the elderly. Despite a number of large clinical trial efforts, metastatic sarcoma remains a lethal disease, and there have been no meaningful advances in therapy or improvements in patient outcomes for decades. Mycobacterium w (Mw, also known as Mycobacterium indicus pranii) is a non-pathogenic strain of mycobacterium which has been used as an immunomodulator against leprosy, tuberculosis and several cancers and is approved for treatment of NSCLC along with chemotherapy in India. Mw promotes a Th1 immune response and its administration in tumor bearing animals is associated with an increase in total number of tumor infiltrating immune cells (TIIC) with decrease in FOXP3 and PD-1 expressing TIIC in pancreatic cancer and melanoma. Previous studies in our lab have shown that Mw promotes mature dendritic cell and activated CD8+ T cell accumulation within the tumor microenvironment in a mouse model of pancreatic cancer. We compared the effects Mw with standard of care doxorubicin on OS tumor progression in a subcutaneous K7M2 syngeneic mouse model. Mw treatment was more effective at tumor inhibition than doxorubicin. Immunohistochemistry analyses of OS tumors revealed an increase in macrophages following Mw treatment. We aim to further analyze the tumor immune microenvironment using a panel of 28 antibodies to determine alterations due to Mw treatment. With these results we hope to show that Mw is a promising candidate for further development as a therapy for OS.

Citation Format: Kirsten Stefan, Arpit Dheeraj, Dhanir Tailor, Sushil Kumar, Wenqi Li, Rajiv Modi, Manjul Joshipura, Bakulesh Khamar, Lara E. Davis, Sanjay V. Malhotra. The role of Mycobacterium w as a novel treatment for osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 554.

Nirogacestat, a γ-Secretase Inhibitor for Desmoid Tumors

BACKGROUND

Desmoid tumors are rare, locally aggressive, highly recurrent soft-tissue tumors without approved treatments.

METHODS

We conducted a phase 3, international, double-blind, randomized, placebo-controlled trial of nirogacestat in adults with progressing desmoid tumors according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Patients were assigned in a 1:1 ratio to receive the oral γ-secretase inhibitor nirogacestat (150 mg) or placebo twice daily. The primary end point was progression-free survival.

RESULTS

From May 2019 through August 2020, a total of 70 patients were assigned to receive nirogacestat and 72 to receive placebo. Nirogacestat had a significant progression-free survival benefit over placebo (hazard ratio for disease progression or death, 0.29; 95% confidence interval, 0.15 to 0.55; P<0.001); the likelihood of being event-free at 2 years was 76% with nirogacestat and 44% with placebo. Between-group differences in progression-free survival were consistent across prespecified subgroups. The percentage of patients who had an objective response was significantly higher with nirogacestat than with placebo (41% vs. 8%; P<0.001), with a median time to response of 5.6 months and 11.1 months, respectively; the percentage of patients with a complete response was 7% and 0%, respectively. Significant between-group differences in secondary patient-reported outcomes, including pain, symptom burden, physical or role functioning, and health-related quality of life, were observed (P≤0.01). Frequent adverse events with nirogacestat included diarrhea (in 84% of the patients), nausea (in 54%), fatigue (in 51%), hypophosphatemia (in 42%), and maculopapular rash (in 32%); 95% of adverse events were of grade 1 or 2. Among women of childbearing potential receiving nirogacestat, 27 of 36 (75%) had adverse events consistent with ovarian dysfunction, which resolved in 20 women (74%).

CONCLUSIONS

Nirogacestat was associated with significant benefits with respect to progression-free survival, objective response, pain, symptom burden, physical functioning, role functioning, and health-related quality of life in adults with progressing desmoid tumors. Adverse events with nirogacestat were frequent but mostly low grade. (Funded by SpringWorks Therapeutics; DeFi ClinicalTrials.gov number, NCT03785964.).

Protein arginine methyltransferase 5 is essential for oncogene product EWSR1-ATF1-mediated gene transcription in clear cell sarcoma

Transcription dysregulation is common in sarcomas driven by oncogenic transcription factors. Clear cell sarcoma of soft tissue (CCSST) is a rare sarcoma with poor prognosis presently with no therapy. It is characterized by a balanced t(12;22) (q13;q12) chromosomal translocation, resulting in a fusion of the Ewing's sarcoma gene EWSR1 with activating transcription factor 1 (ATF1) to give an oncogene EWSR1-ATF1. Unlike normal ATF1, whose transcription activity is dependent on phosphorylation, EWSR1-ATF1 is constitutively active to drive ATF1-dependent gene transcription to cause tumorigenesis. No EWSR1-ATF1-targeted therapies have been identified due to the challenges in targeting intracellular transcription factors. Through proteomics screening to identify potential druggable targets for CCSST, we discovered protein arginine methyltransferase 5 (PRMT5) as a novel protein to interact with EWSR1-ATF1. PRMT5 is a type II protein arginine methyltransferase to symmetrically dimethylate arginine residues in substrate proteins to regulate a diverse range of activities including gene transcription, RNA splicing, and DNA repair. We found that PRMT5 enhances EWSR1-ATF1-mediated gene transcription to sustain CCSST cell proliferation. Genetic silencing of PRMT5 in CCSST cells resulted in severely impaired cell proliferation and EWSR1-ATF1-driven transcription. Furthermore, we demonstrate that the clinical-stage PRMT5 inhibitor JNJ-64619178 potently and efficaciously inhibited CCSST cell growth in vitro and in vivo. These results provide new insights into PRMT5 as a transcription regulator and warrant JNJ-64619178 for further clinical development to treat CCSST patients.

A phase II trial of regorafenib in patients with advanced Ewing sarcoma and related tumors of soft tissue and bone: SARC024 trial results

BACKGROUND

Regorafenib is one of several FDA-approved cancer therapies targeting multiple tyrosine kinases. However, there are few subtype-specific data regarding kinase inhibitor activity in sarcomas. We report results of a single arm, phase II trial of regorafenib in advanced Ewing family sarcomas.

METHODS

Patients with metastatic Ewing family sarcomas (age ≥ 18, ECOG 0-2, good organ function) who had received at least one line of therapy and experienced progression within 6 months of registration were eligible. Prior kinase inhibitors were not allowed. The initial dose of regorafenib was 160 mg oral days 1-21 of a 28-day cycle. The primary endpoint was estimating progression-free rate (PFR) at 8 weeks employing RECIST 1.1.

RESULTS

Thirty patients (median age, 32 years; 33% women [10 patients]; bone primary, 40%; extraskeletal primary, 60%) enrolled at 14 sites. The most common grade 3 or higher toxicities were hypophosphatemia (5 grade 3, 1 grade 4), hypertension (2 grade 3), elevated ALT (2 grade 3). Sixteen patients required dose reductions, most often for hypophosphatemia (n = 7 reductions in 6 patients); two stopped regorafenib for toxicity. There was one death unrelated to treatment in the 30-day post-study period. Median progression-free survival (PFS) was 14.8 weeks (95% CI 7.3-15.9); PFR at 8 weeks by Kaplan-Meier analysis was 63% (95% CI 46-81%). The RECIST 1.1 response rate was 10%. Median OS was 53 weeks (95% CI 37-106 weeks).

CONCLUSIONS

Regorafenib has modest activity in the Ewing family sarcomas. Toxicity was similar to that seen in approval studies.

Phase 1/2 study of devimistat in combination with hydroxychloroquine (HCQ) in patients with relapsed or refractory (R/R) clear cell sarcoma (CCS)

TPS11595

Background: CCS of the soft tissues is a rare and aggressive subtype of sarcoma that often starts in the tendons of the arms or legs. It is molecularly characterized by t(12;22)(q13;q12) translocation, resulting in EWSR1-ATF1 or EWSR1-CREB1 gene fusion. Despite reports of occasional responses to systemic therapies, currently available therapies have shown limited efficacy in advanced CCS. Therefore, there is a significant unmet medical need for more active agents in CCS. Devimistat is a stable intermediate of a lipoate analog that inhibits pyruvate dehydrogenase and α-ketoglutarate dehydrogenase enzymes of the tricarboxylic acid (TCA) cycle preferentially within the mitochondria of cancer cells. Devimistat induces autophagy in cancer cells. In a metastatic mouse model of CCS, treatment with devimistat in combination with chloroquine significantly suppressed tumor growth (Egawa et al, 2018). Based on this data, we hypothesized that inhibition of autophagy with HCQ may sensitize cancer cells to devimistat with increased efficacy and acceptable toxicity. Given its expected synergy, we have initiated a single-arm phase I/II prospective, multicenter, open-label, non-randomized study to evaluate maximally tolerated dose (MTD), safety, and efficacy of devimistat in combination with HCQ in patients with R/R CCS. Methods: In the phase 1 portion of the study, patients with R/R CCS and other fusion-positive R/R sarcomas will be enrolled and a standard 3+3 design will be followed to evaluate toxicity, MTD, and recommended phase 2 dose. There will be two patient groups based on weight, and dose escalation will be conducted separately for each group. Starting dose of HCQ will be 5mg/kg PO BID for patients < 45 kg and 200 mg PO BID for patients ≥45 kg on days 1 through 5 of every 28 days. The first dose of HCQ each day will be followed 2 hours later by 1,000 mg/m2 devimistat (for patients < 45 kg) and 2,000 mg/m2 of devimistat (for patients ≥ 45 kg) administered over 2 hours. A maximum of 36 patients will be enrolled for the phase I portion, 18 for each patient group. In the phase 2 portion of the study, only relapsed or refractory CCS patients will be enrolled, and the response rate will be determined using RECIST 1.1. In phase 2, pharmacokinetics, duration of response, clinical benefit rate, progression-free survival, overall survival, safety, and patient-reported outcomes will also be assessed. This portion of the study will utilize Simon’s admissible two-stage design with 29 patients. This study started enrolling participants in November 2021 and has dosed six patients to date. The first two dose-escalation cohorts for patients ≥45 kg have been completed without DLT and the third dose level will be opening shortly. Clinical trial information: NCT04593758.

Pregnancy outcomes related to the treatment of sarcomas with anthracyclines and/or ifosfamide during pregnancy

Background

Sarcomas are rare diagnoses but are seen with relative frequency in adolescents and young adults and thus can present in pregnancy. We sought to study the administration of anthracyclines and/or ifosfamide in pregnancy‐associated sarcomas.

Patients and Methods

We conducted a multi‐institutional retrospective study, identifying sarcoma patients who received anthracyclines and/or ifosfamide during pregnancy. Chart review identified variables related to demographics, cancer diagnosis, therapies, and outcome of the patient and fetus. Wilcoxon rank‐sum test compared two independent samples.

Results

We identified 13 patients at seven institutions with sarcoma who received anthracyclines and/or ifosfamide during pregnancy, including four bone sarcomas and nine soft tissue sarcomas diagnosed at a mean gestational age of 16.7 ± 5.9 weeks. Only nine patients had live births (9/13, 69.2%), with mean gestational age of 30.8 ± 3.8 weeks at delivery. The four patients with pregnancy loss all received both doxorubicin and ifosfamide, with chemotherapy initiated at 15.5 weeks as compared with 21.3 weeks for those patients with live births (p = 0.016).

Conclusion

In this multi‐institutional study of sarcoma chemotherapy regimens administered during pregnancy, we found a high rate of fetal demise that was seen only in patients receiving both doxorubicin and ifosfamide and statistically more likely with chemotherapy initiation earlier in the second trimester. While limited by a small sample size, our study represents the largest study of sarcoma patients that received anthracyclines and/or ifosfamide in pregnancy thus far reported and supports development of an international registry to study concerns raised by our study.

Vimseltinib: A Precision CSF1R Therapy for Tenosynovial Giant Cell Tumors and Diseases Promoted by Macrophages

Macrophages can be co-opted to contribute to neoplastic, neurologic, and inflammatory diseases. Colony-stimulating factor 1 receptor (CSF1R)-dependent macrophages and other inflammatory cells can suppress the adaptive immune system in cancer and contribute to angiogenesis, tumor growth, and metastasis. CSF1R-expressing osteoclasts mediate bone degradation in osteolytic cancers and cancers that metastasize to bone. In the rare disease tenosynovial giant cell tumor (TGCT), aberrant CSF1 expression and production driven by a gene translocation leads to the recruitment and growth of tumors formed by CSF1R-dependent inflammatory cells. Small molecules and antibodies targeting the CSF1/CSF1R axis have shown promise in the treatment of TGCT and cancer, with pexidartinib recently receiving FDA approval for treatment of TGCT. Many small-molecule kinase inhibitors of CSF1R also inhibit the closely related kinases KIT, PDGFRA, PDGFRB, and FLT3, thus CSF1R suppression may be limited by off-target activity and associated adverse events. Vimseltinib (DCC-3014) is an oral, switch control tyrosine kinase inhibitor specifically designed to selectively and potently inhibit CSF1R by exploiting unique features of the switch control region that regulates kinase conformational activation. In preclinical studies, vimseltinib durably suppressed CSF1R activity in vitro and in vivo, depleted macrophages and other CSF1R-dependent cells, and resulted in inhibition of tumor growth and bone degradation in mouse cancer models. Translationally, in a phase I clinical study, vimseltinib treatment led to modulation of biomarkers of CSF1R inhibition and reduction in tumor burden in TGCT patients.

Primary Aortic Angiosarcoma: A Review of Two Cases Highlighting Unique Imaging and Clinical Characteristics

Angiosarcomas are rare vascular connective tissue tumors originating from the tunica intima, media, or adventitia and may arise in large vessels. Here two cases of primary angiosarcoma of the aorta are described that highlight initial manifestations and unique complications from diffuse arterial tumor emboli, which led to delayed cancer diagnosis. In patients with aortic lesions, imaging characteristics must be thoughtfully reconciled with clinical scenarios, particularly in patients with no additional evidence of atherosclerosis or vasculitis. Keywords: Oncology, Neoplasms-Primary, MR-Angiography, Aorta © RSNA, 2021.

Identified Enrollment Challenges of Adolescent and Young Adult Patients on the Nonchemotherapy Arm of Children's Oncology Group Study ARST1321

ARST1321, a trial of patients with advanced soft tissue sarcoma, was the first National Clinical Trials Network study codeveloped by pediatric and adult consortia with two treatment cohorts. We report on the findings of a survey to identify barriers to enrolling adolescent and young adult patients (15-39 years) onto the nonchemotherapy arm. The survey response rate was 31% with a 70% completion rate. Common identified reasons for low accrual in order of decreasing frequency included insufficient funding, lack of study awareness or interest, competing trials, toxicity concerns, philosophical differences in the therapy backbone, and regulatory and infrastructure barriers. Clinical Trials.gov ID: NCT02180867.

GAB1-ABL1 fusions in tumors that have histologic overlap with NTRK-rearranged spindle cell tumors

Fibroblastic spindle cell tumors are a heterogeneous group of rare soft tissue tumors that are increasingly recognized as associated with a variety of kinase gene fusions. We report two cases of GAB1-ABL1 fusions in spindle cell tumors that histologically overlap with neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell tumors. The first case occurred in a 76-year-old female who had a large deep-seated spindle cell tumor composed of monotonous ovoid to spindle cells in a background of thick stromal collagen bands with prominent hyalinized vessels and inconspicuous mitoses (<1/10 HPF). Immunohistochemical stains showed co-expression of S100 and CD34. A GAB1-ABL1 fusion was detected by whole transcriptome RNA sequencing. The patient had a partial response to imatinib. The second case was previously described as a solitary fibrous tumor, occurring in a 9-year-old female with a cellular spindle cell tumor with patchy CD34 immunoexpression but no expression of S100. Upon clinicopathologic re-review, including anchored multiplex next-generation sequencing, a GAB1-ABL1 fusion was identified. In summary, we report the first two cases of spindle cell tumors with variable expression of CD34 and/or S100, driven by GAB1-ABL1 gene fusions with histologic overlap with NTRK-rearranged spindle cell tumors, suggesting that ABL-fusions may also be oncogenic drivers within this spectrum of tumors. These cases highlight the evolving understanding of fibroblastic spindle cell tumor biology and the utility of sequencing in identifying a targetable alteration.

TK216 for relapsed/refractory Ewing sarcoma: Interim phase 1/2 results

11500

Background: Ewing Sarcoma (ES) is a rare cancer of the young with very few treatment options in the relapsed/refractory (R/R) setting. Fusions of the EWS gene and one of five different ETS transcription factors are dominant drivers of ES. TK216 was designed to bind ETS proteins directly, disrupt protein-protein interactions, and inhibit transcription factor function. TK216 plus vincristine (VCR) exerted synergistic activity in non-clinical models . Here, we report updated interim results of the Phase 1/2 trial of TK216 ± vincristine in R/R ES. Methods: TK216 was administered by continuous IV infusion to adult and pediatric patients (pts) with R/R ES using a 3+3 design. Dosing duration of 7 days was later extended to 10 and 14 days. Dose limiting toxicity was evaluated during Cycle 1. VCR could be added after Cycle 2. The MTD for the 14-day infusion was 200 mg/m2/d, which was selected as the recommended Phase 2 dose (RP2D) for the Expansion cohort, with VCR started in Cycle 1. Results: Thirty-two R/R pts in 9 dose and schedule escalation cohorts, and 31 pts in the Phase 2 Expansion cohort were enrolled. Thirty-five pts were treated at the RP2D. Mean age was 30.6 years and 61% were males. Median prior treatment regimens for recurrent/metastatic ES were 3 (range 0-13). Median time from initial diagnosis of ES to study start was 3.5 years (range 0.3-18.1). Prior procedures included surgery (84%) and radiation (81%). At study entry, all pts had metastases with sites being bone only (13%), pleuropulmonary only (39%), and other metastatic (47%). As of the 20JAN2021 safety cutoff, the most common AEs observed in 62 treated pts, regardless of causality, included anemia (n = 34), neutropenia (n = 30) and fatigue (n = 25). Myelosuppression observed was transient, reversible, and responsive to growth factors. No deaths were attributed to TK216. As of the 06FEB2021 efficacy cut-off, 28/35 pts treated at the RP2D were evaluable for efficacy: Complete response (CR) 7.1%, stable disease (SD) 39.3%, progressive disease (PD) 53.6%, for an overall clinical benefit (CR+PR+SD) rate of 46.4%. SD median duration was 113 days (range 62-213). Three tumor responses were notable. One pt had regression of the target lesion after 2 cycles of TK216 alone, then after 6 cycles of TK216 + VCR therapy a residual non-target lesion was removed, for a surgical CR, without PD at 24 months on study. A second pt had a CR after 6 cycles of combination therapy, without PD at 18 months on study. After 4 cycles of TK216 + VCR therapy, a third pt had a PR of the target lesion, is receiving local therapy for PD of a non-target lesion and remains on study. Pts treated with the RP2D had a longer PFS than those in the dose escalation cohorts. Conclusions: TK216 plus VCR was well tolerated and showed encouraging early evidence of anti-tumor activity in this heavily pre-treated/ high tumor burden ES pt population. Clinical trial information: NCT02657005.

A Randomized, Double-Blind, Placebo-Controlled, Phase II Study of Regorafenib Versus Placebo in Advanced/Metastatic, Treatment-Refractory Liposarcoma: Results from the SARC024 Study

LESSONS LEARNED

The results from the liposarcoma cohort of SARC024 confirm previously published data and do not support the routine use of regorafenib in this patient population. Continued exploration of novel therapies, including combination approaches, is warranted for a patient population in whom limited treatment options exist.

BACKGROUND

Regorafenib is a multitargeted kinase inhibitor with a kinase profile overlapping, but distinct from, pazopanib, an agent approved for recurrent and metastatic non-gastrointestinal stromal tumor (GIST), non-adipocytic soft tissue sarcoma. We conducted a randomized, phase II study of regorafenib versus placebo in refractory liposarcoma patients.

METHODS

Patients with advanced or metastatic, treatment-refractory liposarcoma were randomized 1:1 to receive regorafenib 160 mg or placebo once daily (3 weeks on, 1 week off). Patients with well-differentiated liposarcoma only were excluded. Crossover for placebo was allowed upon progression. The primary endpoint was progression-free survival (PFS), according to RECIST version 1.1.

RESULTS

Forty-eight subjects with liposarcoma (34 dedifferentiated, 12 myxoid/round cell, 2 pleomorphic) were enrolled. Median PFS was 1.87 (95% confidence interval [CI], 0.92-3.67) months for regorafenib versus 2.07 (95% CI, 1.64-3.44) months for placebo; stratified hazard ratio [HR], 0.85 (95% CI, 0.46, 1.58), p = .62. No responses were seen on regorafenib. One PR was observed on placebo. Median overall survival was 6.46 (95% CI, 4.16-23.48) months for regorafenib and 4.89 (95% CI, 3.02-9.77) months for placebo, stratified HR, 0.66 (95% CI, 0.31-1.40), p = .28). Treatment-related adverse events were similar to the known safety profile of regorafenib.

CONCLUSION

Regorafenib did not appear to improve PFS in treatment-refractory liposarcoma. No new significant safety signals were observed.

Tazemetostat in advanced epithelioid sarcoma with loss of INI1/SMARCB1: an international, open-label, phase 2 basket study

BACKGROUND

Epithelioid sarcoma is a rare and aggressive soft-tissue sarcoma subtype. Over 90% of tumours have lost INI1 expression, leading to oncogenic dependence on the transcriptional repressor EZH2. In this study, we report the clinical activity and safety of tazemetostat, an oral selective EZH2 inhibitor, in patients with epithelioid sarcoma.

METHODS

In this open-label, phase 2 basket study, patients were enrolled from 32 hospitals and clinics in Australia, Belgium, Canada, France, Germany, Italy, Taiwan, the USA, and the UK into seven cohorts of patients with different INI1-negative solid tumours or synovial sarcoma. Patients eligible for the epithelioid sarcoma cohort (cohort 5) were aged 16 years or older with histologically confirmed, locally advanced or metastatic epithelioid sarcoma; documented loss of INI1 expression by immunohistochemical analysis or biallelic SMARCB1 (the gene that encodes INI1) alterations, or both; and an Eastern Cooperative Oncology Group performance status score of 0-2. Patients received 800 mg tazemetostat orally twice per day in continuous 28-day cycles until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint was investigator-assessed objective response rate measured according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary endpoints were duration of response, disease control rate at 32 weeks, progression-free survival, overall survival, and pharmacokinetic and pharmacodynamic analyses (primary results reported elsewhere). Time to response was also assessed as an exploratory endpoint. Activity and safety were assessed in the modified intention-to-treat population (ie, patients who received one or more doses of tazemetostat). This trial is registered with ClinicalTrials.gov, NCT02601950, and is ongoing.

FINDINGS

Between Dec 22, 2015, and July 7, 2017, 62 patients with epithelioid sarcoma were enrolled in the study and deemed eligible for inclusion in this cohort. All 62 patients were included in the modified intention-to-treat analysis. Nine (15% [95% CI 7-26]) of 62 patients had an objective response at data cutoff (Sept 17, 2018). At a median follow-up of 13·8 months (IQR 7·8-19·0), median duration of response was not reached (95% CI 9·2-not estimable). 16 (26% [95% CI 16-39]) patients had disease control at 32 weeks. Median time to response was 3·9 months (IQR 1·9-7·4). Median progression-free survival was 5·5 months (95% CI 3·4-5·9), and median overall survival was 19·0 months (11·0-not estimable). Grade 3 or worse treatment-related adverse events included anaemia (four [6%]) and weight loss (two [3%]). Treatment-related serious adverse events occurred in two patients (one seizure and one haemoptysis). There were no treatment-related deaths.

INTERPRETATION

Tazemetostat was well tolerated and showed clinical activity in this cohort of patients with advanced epithelioid sarcoma characterised by loss of INI1/SMARCB1. Tazemetostat has the potential to improve outcomes in patients with advanced epithelioid sarcoma. A phase 1b/3 trial of tazemetostat plus doxorubicin in the front-line setting is currently underway (NCT04204941).

FUNDING

Epizyme.

A phase Ib study of ribociclib in combination with doxorubicin in advanced soft tissue sarcomas (aSTS)

11548

Background: aSTS are typically treated with single agent doxorubicin (dox). CDK4 inhibitors such as ribociclib (ribo) may have a role in treating STS, which frequently rely on hyperphosphorylation of Rb to evade the Rb checkpoint. We hypothesized that dox efficacy could be increased by inhibiting Rb phosphorylation with a short course of ribo, then removing ribo to permit cell cycle progression prior to dox, thus potentiating the DNA-damaging effects of dox. Methods: Open label, dose-finding study of ribo and dox in dox-naïve patients (pts) with Rb+ aSTS. Rb status determined by IHC. Primary objective to determine the recommended phase 2 dose (RP2D). Secondary objective of anti-tumor activity. Pts received ribo 400-600 mg PO QD x7d followed by 72h rest before dox 60-75 mg/m2 IV, q21d. Pts free from progression of disease after 6 cycles continued on ribo maintenance at 600 mg QD q3/4wk. Dose-limiting toxicity (DLT) period was cycle 1, with target toxicity rate of 30% using a modified toxicity probability interval (mTPI) design. Growth factor support was not allowed during DLT period. Results: 9 screened pts were ineligible by Rb status. 16 pts enrolled with 15 evaluable for dose determination (7 dedifferentiated LPS, 8 other subtypes). 4 of 7 pts treated at starting dose level (400 mg ribo, 75 mg/m2 dox) had a DLT; all febrile neutropenia. 1 of 8 pts treated at dose level -1 (400 mg ribo, 60 mg/m2 dox) had a DLT of gr4 anemia. Febrile neutropenia events occurred during cycle 1, when growth factors were prohibited. Toxicity was similar to historical dox AEs (Table). Two partial responses for overall response rate (ORR) of 13%. Five (33%) were progression-free at 18 wks. Correlative studies ongoing. Conclusions: This study determined a RP2D of ribo 400 mg with dox 60 mg/m2 when used in combination for the treatment of aSTS. Clinical trial information: NCT03009201 . [Table: see text]

A randomized phase II study of gemcitabine (G) alone or with pazopanib (P) in refractory soft tissue sarcoma (STS)

11515

Background: Both G and P are active single-agents in the treatment of STS. We hypothesized that the anti-VEGF-R activity of P could augment the efficacy of G and conducted this study of G+P vs G+placebo (0). Methods: In this multi-center, double-blind study, eligibility included metastatic STS with receipt of 1–3 prior systemic regimens inclusive of an anthracycline. Patients (pts) were stratified by sarcoma subtype (liposarcoma (LPS) vs. other) and study site, then randomly assigned 1:1 to receive G 1000 mg/m2 IV over 30 minutes on days 1 and 8 every 21 days plus either P 800 mg PO or matching 0 daily. The primary endpoint was progression-free survival (PFS). Results: 54 pts were accrued from 2012–2019, Accrual was halted prior to the planned N of 80 due to withdrawal of funding. There were no differences in pt characteristics between the two arms including age (median = 60), sex (M/F 52/48%), histology (LPS 30%, leiomyosarcoma 26%, UPS 15%, synovial 11%, other 17%) and number of prior systemic therapies (median = 1). With a median follow-up of 19.1 months, PFS favored G+P and was significant using the Gehan-Wilcoxon test which favorably weighs earlier events (table). The response rate was 6.9% on the G+P arm and 8.0% on the G+0 arm; response rate was 22% for LPS treated with G+P. The most common grade ≥3 AEs (G+P v G+0) were: neutropenia (41% vs 40), hypertension (17% v 4), anemia (7% v 12). One patient died of hepatic failure on the G+P arm. Conclusions: This study demonstrated improved PFS with G+P as compared with G alone. Early termination limited statistical power. G+P is active in LPS, although P regulatory labeling currently limits use for LPS. Clinical trial information: NCT01532687 . [Table: see text]

Enrollment barriers of adolescents and young adults (AYA) on the non-chemotherapy arm of ARST1321

e19214

Background: ARST1321(PAZNTIS): A Phase II/III Randomized Trial of Preoperative Chemoradiation or Preoperative Radiation Plus or Minus Pazopanib (NCT02180867) was the first National Clinical Trials Network (NCTN) study co-developed by pediatric (COG) and adult (NRG Oncology) consortia anticipating enrollment of adolescent and young adult (AYA) cancer patients. ARST1321 had two treatment cohorts, enrolling patients ≥ 2 years of age to either chemotherapy (C) (chemoradiation ± pazopanib) or non-chemotherapy (NC) (radiation ± pazopanib) arms. It was anticipated adults would contribute the majority of enrollments on the NC arm based on prior enrollment patterns. While the C arm accrued as anticipated (with high enrollment of adults and children), the NC arm had low enrollment leading to premature closure. We report on AYA accrual (defined as 15-39 years) to the NC arm and a survey aiming to identify barriers to enrolling AYA patients onto ARST1321. Methods: Our survey was emailed to 161 adult, surgical, and radiation oncologists at large sarcoma centers. A link was sent to an online questionnaire via SurveyMonkey Inc. and responses were reviewed on their platform. Results: 33 patients enrolled on the ARST1321 NC arm, of which 24% were AYA. 25% of AYA enrollments were from non-COG adult cooperative groups. This trial arm was closed in October 2017 after 3.25 years of accrual below anticipated rates. The survey response rate was 31% with a 70% completion rate. Almost half of respondents were medical oncologists with most seeing 50-200 new sarcoma cases/year at an academic institution and 30% in a pediatric environment (divided equally between radiation and surgical oncologists). 70% of respondents have a joint collaboration with their pediatric oncology team with 23% having a joint clinic. 70% of respondents’ sites opened ARST1321 and anticipated 1-5 patients would be eligible for the NC cohort. However, 42% of respondents’ sites had zero patients enrolled on that arm. The most common reasons for not opening the study and/or not enrolling patients on the NC arm included: lack of interest, disagreement with the therapy, lack of a site investigator, premature study closure, patient/family decision, competing trials, insufficient reimbursement, and regulatory delays. Conclusions: Our survey highlights multiple barriers to enrollment of AYA onto cross-NCTN consortia clinical trials spanning the age spectrum. The information obtained will help inform investigators aiming to effectively design, enroll, and conduct similar trial efforts for AYA in the future.

Correlative Analyses of the SARC028 Trial Reveal an Association Between Sarcoma-Associated Immune Infiltrate and Response to Pembrolizumab

PURPOSE

We recently reported a 17.5% objective RECIST 1.1 response rate in a phase II study of pembrolizumab in patients with advanced sarcoma (SARC028). The majority of responses occurred in undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS). We sought to determine whether we can identify immune features that correlate with clinical outcomes from tumor tissues obtained pre- and on-treatment.

PATIENTS AND METHODS

Pretreatment (n = 78) and 8-week on-treatment (n = 68) tumor biopsies were stained for PD-L1 and multiplex immunofluorescence panels. The density of positive cells was quantified to determine associations with anti-PD-1 response.

RESULTS

Patients that responded to pembrolizumab were more likely to have higher densities of activated T cells (CD8+ CD3+ PD-1+) and increased percentage of tumor-associated macrophages (TAM) expressing PD-L1 pre-treatment compared with non-responders. Pre-treatment tumors from responders also exhibited higher densities of effector memory cytotoxic T cells and regulatory T cells compared with non-responders. In addition, higher density of cytotoxic tumor-infiltrating T cells at baseline correlated with a better progression-free survival (PFS).

CONCLUSIONS

We show that quantitative assessments of CD8+ CD3+ PD-1+ T cells, percentage of TAMs expressing PD-L1, and other T-cell densities correlate with sarcoma response to pembrolizumab and improved PFS. Our findings support that multiple cell types present at the start of treatment may enhance tumor regression following anti-PD-1 therapy in specific advanced sarcomas. Efforts to confirm the activity of pembrolizumab in an expansion cohort of patients with UPS/DDLPS are underway.

Population-based study of the prevalence and management of self-reported high pain scores in patients with non-resected pancreatic adenocarcinoma

BACKGROUND

Pain is a common debilitating symptom in pancreatic adenocarcinoma. This cohort study examined the use of, and factors associated with, pain-directed interventions for a high pain score in patients with non-curable pancreatic adenocarcinoma.

METHODS

Administrative databases were linked and patients with non-resected pancreatic adenocarcinoma diagnosed between 2010 and 2016, who reported one or more Edmonton Symptom Assessment System (ESAS) score, were identified. A high pain score was defined as an ESAS score of at least 4. Outcomes were pain-directed interventions: opiates (in patients aged 65 years or more with universal drug coverage), nerve block and radiation therapy for a high pain score. Reduction in pain score of at least 1 point after pain-directed intervention was also evaluated. Modified Poisson regression was used to examine factors associated with pain-directed intervention.

RESULTS

Among 2623 patients with a median age of 67 years, 1223 (46·6 per cent) were women, and 1621 (61·8 per cent) reported a high pain score at a median of 38 days after diagnosis. Of those with a high pain score, 75·6 per cent (688 of 910) received opiates, 13·5 per cent (219 of 1621) radiation and 1·2 per cent (19 of 1621) nerve block. The pain score decreased in 62·1 per cent of patients after administration of opiates, 73·4 per cent after radiation and all patients after nerve block. In multivariable analysis, no patient factor (age, sex, co-morbidity burden, rurality, income quintile) was associated with receipt of non-opiate pain-directed intervention for a high pain score. In patients aged at least 65 years, advanced age was associated with lower odds of opiate use.

CONCLUSION

Opiates are the most common pain-directed intervention for non-curable pancreatic adenocarcinoma, whereas radiation therapy and nerve blocks are seldom used. The lack of association between pain-directed interventions and patient factors points toward practice-driven patterns.

Feasibility of Treating Adults with Ewing or Ewing-Like Sarcoma with Interval-Compressed Vincristine, Doxorubicin, and Cyclophosphamide Alternating with Ifosfamide and Etoposide

BACKGROUND

Vincristine, doxorubicin, and cyclophosphamide (VDC) alternating with ifosfamide and etoposide (IE) administered every 2 weeks demonstrated a superior event-free survival compared with 3-week dosing in a landmark pediatric trial and is now standard of care for younger patients. Only 12% of patients enrolled in that trial were over 18 years of age; thus, the feasibility of interval-compressed VDC/IE in adults remains poorly described. We conducted a retrospective analysis of our institutional experience using this regimen.

MATERIALS AND METHODS

Pharmacy administration records at Oregon Health and Science University were reviewed to identify patients with Ewing and Ewing-like sarcoma aged 18 years and older who received VDC/IE every 2 weeks.

RESULTS

We identified 24 patients. Median age was 28 years (range 18-60 years). At diagnosis, 67% had localized disease. The most common primary sites were extremity (38%) and pelvis (17%); another 25% had extraosseous disease. The median interval between cycles was 15.0 days, with no difference between patients aged <30 years versus ≥30 years. The median number of admissions for toxicity per patient was two, primarily for febrile neutropenia. Early treatment discontinuation occurred in 17%. Dose reductions were minimal, with mean cumulative doses achieved comparable to original planned dose and no difference between patients aged <30 years versus ≥30 years.

CONCLUSION

For adults with Ewing and Ewing-like sarcoma, administration of interval-compressed chemotherapy is feasible, without significant dose reductions required. Our results are comparable to prior studies involving a primarily pediatric population.

IMPLICATIONS FOR PRACTICE

For Ewing sarcoma, interval-compressed vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide administered every 2 weeks rather than every 3 weeks has been shown to improve event-free survival in pediatric patients. However, in adults, oncologists may be hesitant to pursue interval-compressed therapy because of concerns for feasibility. In the adult population in this study, a median interval between cycles of 15.0 days (mean 17.0 days) was achieved, comparable to the interval achieved in AEWS0031 (median 15.0, mean 17.3 days). Given that this was achieved without unexpected toxicity or substantial dose reductions and that clinical outcomes were favorable compared with adult historical controls, these results support the use of this regimen in adults.

Abstract CT110: CDK4 inhibition prior to doxorubicin for advanced sarcomas: A Phase IB trial

Background

The majority of high-grade sarcomas exploit pathologic hyperphosphorylation of Rb protein (pRb) as a mechanism to evade the G1/S cell cycle checkpoint. CDK4/6 inhibitors such as ribociclib block phosphorylation of pRb, but have minimal efficacy as single agents beyond breast cancer and liposarcoma. Combinations of chemotherapy with concurrent CDK4/6 inhibition may decrease the efficacy of cytotoxic agents by reducing the number of tumor cells actively progressing through the cell cycle.

We hypothesized that an alternative dosing strategy could be employed to increase the efficacy of sarcoma chemotherapy, namely CDK4 inhibition-induced cell cycle synchronization. To test this in vitro, we briefly treated pRb-intact sarcoma cells lines with a CDK4/6 inhibitor, then allowed a period of washout prior to exposure to cytotoxic chemotherapy. This approach results in an increased proportion of actively cycling cells at time of chemotherapy treatment as determined by immunoblotting, flow cytometry and BrdU incorporation, as well as increased sensitivity to doxorubicin in MTS assays. In vivo experiments in a xenograft model showed modest efficacy of CDK4/6 monotherapy. Further, compared to chemotherapy alone, the addition of ribociclib for three days prior to chemotherapy resulted in significant survival prolongation (21.5 vs 40.5 days, p=0.008).

We therefore designed, “A Phase 1B Study of Ribociclib in Combination with Doxorubicin in Advanced Soft Tissue Sarcomas” (NCT03009201).

Methods

This is a single-institution, single-arm, dose-finding study. Eligible subjects are ≥12yo with metastatic or advanced soft tissue sarcoma (STS) and archival tumor tissue that is IHC-positive for pRb, since intact pRb is necessary for effective CDK4/6 inhibition. Prior systemic therapy with anthracycline is exclusionary.

Each 21-day cycle includes 1 week of ribociclib PO daily followed by 3 days of rest prior to doxorubicin dose. Subjects without disease progression after 6 cycles are allowed to continue ribociclib maintenance monotherapy. Subjects receive treatment at one of three dosing levels per a modified toxicity probability interval (mTPI) design: ribociclib 400 mg / doxorubicin 75 mg/m2 (starting dose), ribociclib 600 mg / doxorubicin 75 mg/m2 (dose level +1), or ribociclib 400 mg / doxorubicin 60 mg/m2 (dose level -1).

A fresh tumor biopsy is performed on Day 7 of ribociclib during Cycle 1. Correlative studies to investigate potential predictive biomarkers include comparison of archival and biopsy tissue by immunoblotting and multiplex IHC as well as cell cycle analysis of peripheral blood mononuclear cells by flow cytometry at baseline, C1D7 and C1D10.

Enrollment is continuing as planned, with 47% of subjects enrolled as of December 2018.

Note: This abstract was not presented at the meeting.

Citation Format: Lara E. Davis, Kevin Nusser, Janet Pittsenbarger, Sierra Bertolone-Smith, Phil Norr, Chris W. Ryan. CDK4 inhibition prior to doxorubicin for advanced sarcomas: A Phase IB trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT110.

Randomized Double-Blind Phase II Study of Regorafenib in Patients With Metastatic Osteosarcoma

PURPOSE

SARC024 is a phase II clinical trial of the multikinase inhibitor regorafenib in specific sarcoma subtypes, including advanced osteosarcoma. We hypothesized that regorafenib would improve progression-free survival (PFS) in patients with sarcoma and report the results of the osteosarcoma cohort.

PATIENTS AND METHODS

This trial enrolled patients with progressive metastatic osteosarcoma with measurable disease by RECIST who had received at least one prior line of therapy. Patients were randomly assigned at a ratio of one to one to regorafenib or placebo. Crossover was allowed at time of disease progression. PFS was the primary end point of the study, which was powered to detect a difference of at least 3 months in median PFS.

RESULTS

Forty-two patients from 12 centers were enrolled between September 2014 and May 2018. Median age was 37 years (range, 18 to 76 years). Patients had received an average of 2.3 prior therapy regimens. Ten patients receiving placebo crossed over to active drug at time of progression. Study enrollment was stopped early, after a data safety monitoring committee review. Median PFS was significantly improved with regorafenib versus placebo: 3.6 months (95% CI, 2.0 to 7.6 months) versus 1.7 months (95% CI, 1.2 to 1.8 months), respectively (hazard ratio, 0.42; 95% CI, 0.21 to 0.85; P = .017). In the context of the crossover design, there was no statistically significant difference in overall survival. Fourteen (64%) of 22 patients initially randomly assigned to regorafenib experienced grade 3 to 4 events attributed to treatment, including one grade 4 colonic perforation.

CONCLUSION

The study met its primary end point, demonstrating activity of regorafenib in patients with progressive metastatic osteosarcoma. No new safety signals were observed. Regorafenib should be considered a treatment option for patients with relapsed metastatic osteosarcoma.

Factors associated with receipt of symptom screening in the year after cancer diagnosis in a universal health care system: a retrospective cohort study

Purpose

Patient-reported symptom data are collected prospectively by a provincial cancer agency to mitigate the significant symptom burden that patients with cancer experience. However, an assessment of whether such symptom screening occurs uniformly for those patients has yet to be performed. In the present study, we investigated patient, disease, and health system factors associated with receipt of symptom screening in the year after a cancer diagnosis.

Methods

Patients diagnosed with cancer between 2007 and 2014 were identified. We measured whether 1 or more symptom screenings were recorded in the year after diagnosis. A multivariable modified Poisson regression with robust error variance was used to identify predictors [age, comorbidity, rurality, socioeconomic status, immigration status, cancer site, registration at a regional cancer centre (cc), and year of diagnosis] of being screened for symptoms.

Results

Of 425,905 patients diagnosed with cancer, 163,610 (38%) had 1 or more symptom screening records in the year after diagnosis, and 75% survived at least 1 year. We identified variability in symptom screening by primary cancer site, regional cc, age, sex, comorbidity, material deprivation, rurality of residence, and immigration status. Patients who had been diagnosed with melanoma or endocrine cancers, who were not registered at a regional cc, who lived in the most urban areas, who were elderly, and who were immigrants were least likely to undergo symptom screening after diagnosis.

Conclusions

Our evaluation of the implementation of a population-based symptom screening program in a universal health care system identified populations who are at risk for not receiving screening and who are therefore future targets for improvements in population symptom screening and better management of cancer-related symptoms at diagnosis.

Safety and efficacy of high-dose methotrexate for osteosarcoma in adolescents compared with young adults

Background

Doxorubicin, cisplatin, and high‐dose methotrexate (HDMTX) are the backbone of pediatric osteosarcoma treatment. However, due to toxicity concerns and the lack of data regarding efficacy in adults, high‐dose methotrexate is rarely used in the adult population.

Methods

This single‐center retrospective study examined 33 patients who received HDMTX (12 g/m², maximum 20 g) for the treatment of osteosarcoma at Oregon Health and Science University (OHSU) from 2011 to 2017. Time to serum methotrexate level ≤0.1 µmol/L was the primary outcome. Secondary outcomes included number of HDMTX doses received, methotrexate‐related toxicities, and disease outcomes including histologic response at resection and metastasis‐free survival.

Results

Median age was 20 years [range 7‐38]; 14 patients ≤18 years old and 19 patients >18 years old. Median time to clearance for patients ≤18 years was 79 hours (range 63‐116) compared to 120 hours (range 77‐315) for patients >18 years (P < 0.001). No correlation between age and histologic response at resection was observed (P = 0.50), but there was a significant positive correlation between the number of HDMTX doses received before resection and histologic response (r = 0.49, P = 0.006). There was no significant difference in metastasis‐free survival between age groups, although a trend toward improved survival was noted for patients who received at least seven doses of HDMTX.

Conclusion

Age over 18 years correlates with delayed methotrexate clearance and fewer administered doses of methotrexate, without increased toxicity. The potential benefit of HDMTX in young adults with osteosarcoma may outweigh toxicity risks.

CDK4/6 Inhibitors: The Mechanism of Action May Not Be as Simple as Once Thought

CDK4/6 inhibitors are among a new generation of therapeutics. Building upon the striking success of the combination of CDK4/6 inhibitors and the hormone receptor antagonist letrozole in breast cancer, many other combinations have recently entered clinical trials in multiple diseases. To achieve maximal benefit with CDK4/6 inhibitors it will be critical to understand the cellular mechanisms by which they act. Here we highlight the mechanisms by which CDK4/6 inhibitors can exert their anti-tumor activities beyond simply enforcing cytostatic growth arrest, and discuss how this knowledge may inform new combinations, improve outcomes, and modify dosing schedules in the future.

Pseudoprogression of CNS metastatic disease of alveolar soft part sarcoma during anti-PDL1 treatment

Immune checkpoint inhibitors are increasingly used in treatment of metastatic renal cell carcinoma, melanoma, and nonsmall cell lung cancer, as well as in clinical trials for novel targets. We present a pediatric patient with metastatic alveolar soft part sarcoma who was treated with MPDL3280 (Atezolizumab), a monoclonal anti-programmed death ligand-1 antibody. Imaging results for the patient suggested disease progression of multiple brain metastases with stable systemic disease. The patient met response evaluation criteria in solid tumors (RECIST) criteria of progression of disease and was removed from treatment with MPDL3280. Subsequent surgical resection of the brain lesions revealed nonviable tumor with extensive lymphocytic infiltrates consistent with pseudoprogression. This case report adds to a growing number of reports that question reliance on RECIST criteria and suggest need for further refinement of RECIST or irRECIST during immune checkpoint inhibitor treatment for central nervous system metastatic lesions.

Osteosarcoma, Chondrosarcoma, and Chordoma

Osteosarcoma (OS), chondrosarcoma, and chordoma are characterized by multiple challenges to the investigator, clinician, and patient. One consequence of their rarity among sarcomas, as well as their biologic and clinical heterogeneity, is that management guidelines are inadequate to inform the range of individual patient-treatment decisions from diagnosis, approaches to surgery, chemotherapy, radiotherapy, treatment of recurrence, palliative care, and quality of survivorship. Of high-grade sarcomas, OSs are among the most curable, with more than two-thirds of patients with localized disease likely to achieve long-term survival. Neoadjuvant chemotherapy comprising cisplatin, doxorubicin, and methotrexate with intercalated surgery is the standard of care for resectable OS in those younger than 40 years. Outcomes for OS presenting with unresectable metastases or recurrent disease, or in those older than 40 years are generally poor. Overall results have improved little for all patients with OS, and new treatments are needed. Surgical resection remains the cornerstone of management for chondrosarcoma and chordoma. However, the application of new biologic insights to therapeutic development indicates that improved treatments may soon be routine for patients with chondrosarcoma and chordoma for whom surgery alone is inadequate. For all these uncommon diseases, patients should be offered specialist expert care delivered by experienced multidisciplinary teams in high-volume centers.

Pembrolizumab in advanced soft-tissue sarcoma and bone sarcoma (SARC028): a multicentre, two-cohort, single-arm, open-label, phase 2 trial

BACKGROUND

Patients with advanced sarcomas have a poor prognosis and few treatment options that improve overall survival. Chemotherapy and targeted therapies offer short-lived disease control. We assessed pembrolizumab, an anti-PD-1 antibody, for safety and activity in patients with advanced soft-tissue sarcoma or bone sarcoma.

METHODS

In this two-cohort, single-arm, open-label, phase 2 study, we enrolled patients with soft-tissue sarcoma or bone sarcoma from 12 academic centres in the USA that were members of the Sarcoma Alliance for Research through Collaboration (SARC). Patients with soft-tissue sarcoma had to be aged 18 years or older to enrol; patients with bone sarcoma could enrol if they were aged 12 years or older. Patients had histological evidence of metastatic or surgically unresectable locally advanced sarcoma, had received up to three previous lines of systemic anticancer therapy, had at least one measurable lesion according to the Response Evaluation Criteria In Solid Tumors version 1.1, and had at least one lesion accessible for biopsy. All patients were treated with 200 mg intravenous pembrolizumab every 3 weeks. The primary endpoint was investigator-assessed objective response. Patients who received at least one dose of pembrolizumab were included in the safety analysis and patients who progressed or reached at least one scan assessment were included in the activity analysis. Accrual is ongoing in some disease cohorts. This trial is registered with ClinicalTrials.gov, number NCT02301039.

FINDINGS

Between March 13, 2015, and Feb 18, 2016, we enrolled 86 patients, 84 of whom received pembrolizumab (42 in each disease cohort) and 80 of whom were evaluable for response (40 in each disease cohort). Median follow-up was 17·8 months (IQR 12·3-19·3). Seven (18%) of 40 patients with soft-tissue sarcoma had an objective response, including four (40%) of ten patients with undifferentiated pleomorphic sarcoma, two (20%) of ten patients with liposarcoma, and one (10%) of ten patients with synovial sarcoma. No patients with leiomyosarcoma (n=10) had an objective response. Two (5%) of 40 patients with bone sarcoma had an objective response, including one (5%) of 22 patients with osteosarcoma and one (20%) of five patients with chondrosarcoma. None of the 13 patients with Ewing's sarcoma had an objective response. The most frequent grade 3 or worse adverse events were anaemia (six [14%]), decreased lymphocyte count (five [12%]), prolonged activated partial thromboplastin time (four [10%]), and decreased platelet count (three [7%]) in the bone sarcoma group, and anaemia, decreased lymphocyte count, and prolonged activated partial thromboplastin time in the soft-tissue sarcoma group (three [7%] each). Nine (11%) patients (five [12%] in the bone sarcoma group and four [10%] in the soft-tissue sarcoma group) had treatment-emergent serious adverse events (SAEs), five of whom had immune-related SAEs, including two with adrenal insufficiency, two with pneumonitis, and one with nephritis.

INTERPRETATION

The primary endpoint of overall response was not met for either cohort. However, pembrolizumab showed encouraging activity in patients with undifferentiated pleomorphic sarcoma or dedifferentiated liposarcoma. Enrolment to expanded cohorts of those subtypes is ongoing to confirm and characterise the activity of pembrolizumab.

FUNDING

Merck, SARC, Sarcoma Foundation of America, QuadW Foundation, Pittsburgh Cure Sarcoma, and Ewan McGregor.

Integration of genomic, transcriptomic and functional profiles of aggressive osteosarcomas across multiple species

In complex, highly unstable genomes such as in osteosarcoma, targeting aberrant checkpoint processes (metabolic, cell cycle or immune) may prove more successful than targeting specific kinase or growth factor signaling pathways. Here, we establish a comparative oncology approach characterizing the most lethal osteosarcomas identified in a biorepository of tumors from three different species: human, mouse and canine. We describe the development of a genetically-engineered mouse model of osteosarcoma, establishment of primary cell cultures from fatal human tumors, and a biorepository of osteosarcoma surgical specimens from pet dogs. We analyzed the DNA mutations, differential RNA expression and in vitro drug sensitivity from two phenotypically-distinct cohorts: tumors with a highly aggressive biology resulting in death from rapidly progressive, refractory metastatic disease, and tumors with a non-aggressive, curable phenotype. We identified ARK5 (AMPK-Related Protein Kinase 5, also referred to as NUAK Family Kinase 1) as a novel metabolic target present in all species, and independent analyses confirmed glucose metabolism as the most significantly aberrant cellular signaling pathway in a model system for highly metastatic tumors. Pathway integration analysis identified Polo Like Kinase 1 (PLK1)-mediated checkpoint adaptation as critical to the survival of a distinctly aggressive osteosarcoma. The tumor-associated macrophage cytokine CCL18 (C-C Motif Chemokine Ligand 18) was significantly over-expressed in aggressive human osteosarcomas, and a clustering of mutations in the BAGE (B Melanoma Antigen) tumor antigen gene family was found. The theme of these features of high risk osteosarcoma is checkpoint adaptations, which may prove both prognostic and targetable.

Clinical trial enrollment of adolescents and young adults with sarcoma

More than half of all sarcomas occur in adolescents and young adults (AYAs) aged 15 to 39 years. After the publication of the AYA series in the April 1, 2016 issue of Cancer, several leaders in the field of sarcoma across disciplines gathered to discuss the status of sarcoma clinical research in AYAs. They determined that a focused effort to include the underrepresented and understudied AYA population in current and future sarcoma clinical trials is overdue. Trial enrichment for AYA-aged sarcoma patients will produce more meaningful results that better represent the disease's biology, epidemiology, and treatment environment. To address the current deficit, this commentary outlines changes believed to be necessary to expediently achieve an increase in the enrollment of AYAs in sarcoma clinical trials. Cancer 2017;123:3434-40. © 2017 American Cancer Society.

An Oncogenic NTRK Fusion in a Patient with Soft-Tissue Sarcoma with Response to the Tropomyosin-Related Kinase Inhibitor LOXO-101

Oncogenic TRK fusions induce cancer cell proliferation and engage critical cancer-related downstream signaling pathways. These TRK fusions occur rarely, but in a diverse spectrum of tumor histologies. LOXO-101 is an orally administered inhibitor of the TRK kinase and is highly selective only for the TRK family of receptors. Preclinical models of LOXO-101 using TRK-fusion-bearing human-derived cancer cell lines demonstrate inhibition of the fusion oncoprotein and cellular proliferation in vitro, and tumor growth in vivo. The tumor of a 41-year-old woman with soft-tissue sarcoma metastatic to the lung was found to harbor an LMNA-NTRK1 gene fusion encoding a functional LMNA-TRKA fusion oncoprotein as determined by an in situ proximity ligation assay. In a phase I study of LOXO-101 (ClinicalTrials.gov no. NCT02122913), this patient's tumors underwent rapid and substantial tumor regression, with an accompanying improvement in pulmonary dyspnea, oxygen saturation, and plasma tumor markers.

SIGNIFICANCE

TRK fusions have been deemed putative oncogenic drivers, but their clinical significance remained unclear. A patient with a metastatic soft-tissue sarcoma with an LMNA-NTRK1 fusion had rapid and substantial tumor regression with a novel, highly selective TRK inhibitor, LOXO-101, providing the first clinical evidence of benefit from inhibiting TRK fusions.

Functionally defined therapeutic targets in diffuse intrinsic pontine glioma

Diffuse Intrinsic Pontine Glioma (DIPG) is a fatal childhood cancer. We performed a chemical screen in patient-derived DIPG cultures along with RNAseq analyses and integrated computational modeling to identify potentially effective therapeutic strategies. The multi-histone deacetylase inhibitor panobinostat demonstrated efficacy in vitro and in DIPG orthotopic xenograft models. Combination testing of panobinostat with histone demethylase inhibitor GSKJ4 revealed synergy. Together, these data suggest a promising therapeutic strategy for DIPG.

An Integrated Approach to Anti-Cancer Drug Sensitivity Prediction

A framework for design of personalized cancer therapy requires the ability to predict the sensitivity of a tumor to anticancer drugs. The predictive modeling of tumor sensitivity to anti-cancer drugs has primarily focused on generating functions that map gene expressions and genetic mutation profiles to drug sensitivity. In this paper, we present a new approach for drug sensitivity prediction and combination therapy design based on integrated functional and genomic characterizations. The modeling approach when applied to data from the Cancer Cell Line Encyclopedia shows a significant gain in prediction accuracy as compared to elastic net and random forest techniques based on genomic characterizations. Utilizing a Mouse Embryonal Rhabdomyosarcoma cell culture and a drug screen of 60 targeted drugs, we show that predictive modeling based on functional data alone can also produce high accuracy predictions. The framework also allows us to generate personalized tumor proliferation circuits to gain further insights on the individualized biological pathway.

A case study of personalized therapy for osteosarcoma

BACKGROUND

Effective targeted therapies are needed in sarcomas, but the biological heterogeneity of these tumors has presented a challenge to clinical integration of small molecule inhibitors in sarcoma treatment. Here we outline a process to personalize therapy for sarcomas through a case study of a canine with spontaneous osteosarcoma.

PROCEDURE

Rapid establishment of a primary tumor cell culture is described, followed by efficient functional characterization of the tumor that identified the Src inhibitor dasatinib as the most effective targeted therapy for this individual dog.

RESULTS

Adjuvant dasatinib was administered for a total of 26 weeks following treatment with chemotherapy. Pharmacokinetic studies confirm that a therapeutic serum concentration was achieved at a tolerable dose of 0.75 mg/kg/day. The canine patient remains without evidence of recurrent disease 24 months following initial diagnosis.

CONCLUSIONS

The approach described through this illustrative case study is broadly applicable and might be used for other solid tumors in canines as well as in humans.

A new approach for prediction of tumor sensitivity to targeted drugs based on functional data

Background

The success of targeted anti-cancer drugs are frequently hindered by the lack of knowledge of the individual pathway of the patient and the extreme data requirements on the estimation of the personalized genetic network of the patient’s tumor. The prediction of tumor sensitivity to targeted drugs remains a major challenge in the design of optimal therapeutic strategies. The current sensitivity prediction approaches are primarily based on genetic characterizations of the tumor sample. We propose a novel sensitivity prediction approach based on functional perturbation data that incorporates the drug protein interaction information and sensitivities to a training set of drugs with known targets.

Results

We illustrate the high prediction accuracy of our framework on synthetic data generated from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and an experimental dataset of four canine osteosarcoma tumor cultures following application of 60 targeted small-molecule drugs. We achieve a low leave one out cross validation error of <10% for the canine osteosarcoma tumor cultures using a drug screen consisting of 60 targeted drugs.

Conclusions

The proposed framework provides a unique input-output based methodology to model a cancer pathway and predict the effectiveness of targeted anti-cancer drugs. This framework can be developed as a viable approach for personalized cancer therapy.

Overcoming autopsy barriers in pediatric cancer research

BACKGROUND

More than 13,000 children annually in the United States and Canada under the age of 20 will be diagnosed with cancer at a mortality approaching 20% 1,2. Tumor samples obtained by autopsy provide an innovative way to study tumor progression, potentially aiding in the discovery of new treatments and increased survival rates. The purpose of this study was to identify barriers to autopsies and develop guidelines for requesting autopsies for research purposes.

PROCEDURE

Families of children treated for childhood cancer were referred by patient advocacy groups and surveyed about attitudes and experiences with research autopsies. From 60 interviews, barriers to autopsy and tumor banking were identified. An additional 14 interviews were conducted with medical and scientific experts.

RESULTS

Ninety-three percent of parents of deceased children did or would have consented to a research autopsy if presented with the option; however, only half of these families were given the opportunity to donate autopsy tissue for research. The most significant barriers were the physicians' reluctance to ask a grieving family and lack of awareness about research opportunities.

CONCLUSIONS

The value of donating tumor samples to research via an autopsy should be promoted to all groups managing pediatric cancer patients. Not only does autopsy tumor banking offer a potentially important medical and scientific impact, but the opportunity to contribute this Legacy Gift of autopsy tumor tissue also creates a positive outlet for the grieving family. Taking these findings into account, our multidisciplinary team has developed a curriculum addressing key barriers.

Effect of fetal anaemia on myocardial ischaemia-reperfusion injury and coronary vasoreactivity in adult sheep

AIMS

We investigated whether chronic fetal anaemia affects myocardial infarct in adulthood and elicits functional modifications in adult coronary vasoreactivity.

METHODS

Seven-month-old sheep that were made anaemic in utero and transfused to normal haematocrit before birth were studied. Infarct size was determined by tetrazolium after 1-h ischaemia (occlusion of the mid of left anterior descending artery) and 2-h reperfusion. The dose-response to vasoconstrictors and vasodilators was assessed in small resistance coronary arteries.

RESULTS

There were no significant differences between the animals previously subjected to in utero anaemia and the control animals regarding the percentage infarct size and the area-at-risk to the left ventricle. The ventricular function (dP/dt) was preserved. The percentage infarct size of the area-at-risk (70.7 +/- 3.5%) was larger than that in the controls (49.8 +/- 4.5%) (P = 0.006). The vascular responses were not altered. Endothelium-dependent relaxation to bradykinin (96.0 +/- 2.6% vs. 98.8 +/- 1.0%) was not affected by PGI(2) inhibitor (94.6 +/- 2.6% vs. 98.5 +/- 1.0%) but significantly reduced by the inhibition of nitric oxide (NO) in both anaemic (P < 0.05) and control (P < 0.001) groups with a significant right shift of EC(50) (P < 0.01). The non-NO-non-PGI(2)-mediated relaxation was slightly potentiated in anaemic animals.

CONCLUSIONS

Exposing fetal sheep to in utero anaemia in late gestation for 3 weeks may increase the susceptibility of adult hearts to ischaemia-reperfusion injury without major alterations in coronary vasomotor responsiveness. The impact of in utero anaemia at earlier period of pregnancy and on the earlier or later life of the adult is yet to be further investigated.

Persistent changes in arterial blood gases in fetal sheep

Two anaesthetic protocols were compared using pregnant sheep. In both groups of animals, anaesthesia was induced using an intravenous (i.v.) injection of diazepam and ketamine. The ewes were then intubated for positive pressure ventilation using 0.8 L/min of nitrous oxide and 2 L/min oxygen with 1.1-1.8% halothane. If the ewe showed any signs of awakening, one of two protocols was followed. First, the halothane concentration was increased to 2-3% until the ewe was completely anaesthetized. Second, the halothane concentration was not altered, but the ewe was given doses of i.v. diazepam (0.1 mg/kg) and ketamine (1 mg/kg) until again completely anaesthetized. At the completion of surgery, maternal recovery was rapid and similar between the two groups. However, five days after surgery, the fetal arterial Po(2) and oxygen content of the fetuses receiving additional halothane (1.9 +/- 0.2 kPa and 4.4 +/- 1.0 mL/100 mL) were statistically significantly depressed when compared with the fetuses receiving additional diazepam and ketamine (2.9 +/- 0.1 kPa and 7.0 +/- 0.5 mL/100 mL). These results led us to conclude that certain anaesthetic protocols, in spite of good maternal recovery, can lead to deleterious effects upon the fetus that persist for at least five days after surgery.

Fetal infusions of plasma cause an increase in umbilical vascular resistance in sheep

Earlier studies suggested that the fetal placental circulation is relatively inert with fetal placental flow increasing or decreasing with perfusion pressure. Subsequent studies have demonstrated that the placenta may not be an unreactive vascular bed. The present study was undertaken to determine if plasma infusion-induced hypertension increased fetal placental flow in proportion to the driving pressure across the fetal placental circulation. Six fetal sheep were operated on at 118-122 days to place intravascular catheters and a flow sensor on the common umbilical artery. Starting 6 days later, the fetuses were infused with adult sheep plasma. During the 7-day-long infusion period, they received a total of 1515+/-217 (SD) ml of fluid and 93.2+/-12.0 g of protein. Fetal plasma protein concentrations increased from 34.2+/-2.3 to 77.0+/-9.7 g/l (P<0.0001). Fetal arterial blood pressures rose from 42+/-3 to 59+/-4 mmHg (P<0.01) and venous pressures rose from 2.2+/-0.5 to 4.8+/-0.8 mmHg (P<0.01). In spite of the large increase in driving pressure, fetal placental blood flow remained (statistically) constant (627+/-299 ml/min and 552+/-221 ml/min) while fetal umbilical resistance increased from 0.077+/-0.038 to 0.115+/-0.053 mmHg min/ml (P<0.01). On day 7, plasma renin activity had fallen from 6.7+/-4.2 ng/(ml/h) at preinfusion control to 0.6+/-0.6 ng/(ml/h) (P<0.05) and plasma angiotensin-II concentration had fallen from 33.2+/-26.6 to 6.2+/-3.9 pg/ml, although this fall was not statistically significant (P=0.07). Fetal placental flow did not increase with increased driving pressure across the fetal placental circulation. The increase in fetal placental resistance may be a response to the increase in arterial pressure since there was no increase in flow.

A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults

BACKGROUND

The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults.

METHODS

We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia.

RESULTS

More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild.

CONCLUSIONS

The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

Clinical and laboratory assessment of distal peripheral nerves in Gulf War veterans and spouses

BACKGROUND

The prevalence of symptoms suggesting distal symmetric polyneuropathy (DSP) was reported to be higher among deployed veterans (DV) to the Persian Gulf in 1990-1991 than to control non-deployed veterans (NDV). The authors therefore compared the prevalence of DSP by direct examination of DV and their spouses to control NDV and spouses.

METHODS

The authors performed standardized neurologic examinations on 1,061 DV and 1,128 NDV selected from a cohort of veterans who previously participated in a national mail and telephone survey. Presence of DSP was evaluated by history, physical examination, and standardized electrophysiologic assessment of motor and sensory nerves. Similar examinations were performed without electrophysiologic tests in 484 DV spouses and 533 NDV spouses. Statistical analyses were performed with appropriate adjustments for the stratified sampling scheme.

RESULTS

No differences between adjusted population prevalence of DSP in DV and NDV were found by electrophysiology (3.7% vs 6.3%, p = 0.07), by neurologic examination (3.1% vs 2.6%, p = 0.60), or by the methods combined (6.3% vs 7.3%, p = 0.47). Excluding veterans with non-military service related diseases that may cause DSP did not alter outcomes. DV potentially exposed to neurotoxins from the Khamisiyah ammunition depot explosion did not significantly differ in DSP prevalence compared to non-exposed DV. The prevalence of DSP in DV spouses did not differ from NDV spouses (2.7% vs 3.2%, p = 0.64).

CONCLUSIONS

Neither veterans deployed during the Gulf War era nor their spouses had a higher prevalence of DSP compared to NDV and spouses.

Anaemia stimulates aquaporin 1 expression in the fetal sheep heart

Interstitial fluid fluxes are much greater in the fetus than in the adult, and filtration rates are increased over control in most tissues of the anaemic fetus. Increased capillary filtration may lead to cardiac oedema which, in turn, severely impacts cardiac function. Mechanisms that underlie these differences in flux are incompletely understood. One possible mechanism is an increase in capillary water permeability. Therefore, the goal of our study was to determine the level of expression of the water channel aquaporin 1 (AQP1) during cardiac development and in the anaemic fetal sheep heart. Hearts from chronically instrumented anaemic sheep fetuses and hearts from normal early fetal, late fetal, neonatal and adult sheep were used for Northern and Western analyses and immunohistochemistry. We found that AQP1 mRNA levels were lower in the young fetal left ventricle than in the adult left ventricle (P < 0.05). We also found that cardiac AQP1 expression was increased in anaemic fetuses compared to age-matched controls (P < 0.05). Expression of AQP1 in all groups was greatest in the microvascular endothelium. These data suggest that AQP1 plays an important role in the physiological accommodation to fetal anaemia.