Citations

11505 Background: AL3818 (Catequentinib, Anlotinib) is a novel, orally administered, small molecule tyrosine kinase inhibitor. The primary objective of this Phase 3 study is to evaluate the efficacy of AL3818 monotherapy in patients (pts) with synovial sarcoma (SS) comparing with dacarbazine in randomization setting. Methods: Patients with a diagnosis of synovial sarcoma requiring second line or further line treatment were eligible for enrollment. The regimen was a 21-day cycle with oral AL3818 administered on 14 days on and 7 days off. This phase 3 trial is randomized in 2:1 ratio of AL3818 comparing to dacarbazine with option of crossover after PD of dacarbazine treatment. Progression free survival (PFS) with Log Rank test is the primary endpoint and this trial for SS is currently completed enrolled in US and Italy. Results: Total 79 pts initiated treatment and are evaluable, 52 received AL3818 as treatment arm (T), and 27 received dacarbazine (D) as control arm (C). Arms T/C median ages were 40.5/42.0 years (range: 18-70+) and 20/16 (38.5%/59.3%) were male. Overall, PFS was 2.89 months (95% CI: 2.73 – 6.87) for AL3818 and 1.64 (95% CI: 1.45 – 2.70) for D. The PFS of study met the primary endpoint with a p-value of 0.0015 and a HR of 0.449 (95% CI: 0.270– 0.744). At the month 4, 6, and 12, the percentages of progression free patients for AL3818 were 48.1%, 42.3% and 26.9%; and for D were 14.85%, 11.1% and 3.7%. For grade 3 treatment-related adverse events, 12(23.1%) of pts experienced for AL3818 and 7(25.9%) of pts experienced for D. The most common AL3818 related grade 3 AEs were diarrhea (5.8%) and hypertension (3.8%). Conclusions: This phase III trial demonstrates improved disease control and superior progression free survival for AL3818 vs dacarbazine in advanced SS. In addition, the study further confirms the acceptable benefit-risk profile of AL3818 from the prior randomized Phase 2b soft tissue sarcoma study (NCT02449343). AL3818 is a meaningful treatment option for pts with advanced SS. Clinical trial information: NCT 03016819 Clinical trial information: NCT03016819.

11504 Background: This phase 2, open-label trial (SPEARHEAD-1; NCT04044768) is designed to evaluate the efficacy, safety, and tolerability of afamitresgene autoleucel in 45 patients (pts) with advanced/metastatic synovial sarcoma or Myxoid/Round Cell Liposarcoma (MRCLS). Methods: Eligible pts are HLA-A*02 positive with MAGE-A4-expressing tumors. Pts undergo leukapheresis for collection of autologous T-cells for processing and manufacture into afamitresgene autoleucel cells. Pts were treated with afamitresgene autoleucel doses between 1–10 × 109 transduced T-cells after receiving lymphodepleting chemotherapy. The primary endpoint is overall response rate per RECIST v1.1 by independent review. An independent Data Safety Monitoring Board reviews ongoing safety and benefit: risk during the interventional phase. Results: As of Feb 4, 2021, 32 pts received afamitresgene autoleucel. Of these pts, 59% were male, 87.5% had synovial sarcoma, the median age was 43 yrs (range: 24–73), and they had a median of 3 prior systemic lines of therapy. The MAGE-A4 antigen expression level (histoscore) ranged from 112–300, and the transduced cell dose ranged from 2.7–9.9 x 109. At the data cutoff, 25 pts were evaluable for preliminary efficacy (23 with synovial sarcoma and 2 with MRCLS) and 7 pts (5 with synovial sarcoma and 2 with MRCLS) had insufficient follow-up (<8 weeks follow-up and/or awaiting first scan). Of the 25 evaluable pts, the investigator-assessed responses were: complete response (2 pts), partial response (8 pts), stable disease (11 pts), and progressive disease (4 pts). All responses were confirmed. Nine of the 10 responders had ongoing response at the data cutoff and 3 responders had MAGE-A4 antigen histoscores <200. The most common AEs of any grade (>30% pts) were neutropenia, lymphopenia, nausea, cytokine release syndrome, leukopenia, fatigue, pyrexia, and anemia. Cytokine release syndrome of any grade occurred in 19/32 pts; 95% of those events were ≤Grade 2. No immune effector cell-associated neurotoxicity syndrome (ICANS) has been reported to date. Cytopenia (≥G3) at 4 wks post-infusion was observed in 6 pts (anemia 3 pts, neutropenia 2 pts, and thrombocytopenia 1 pt). Conclusion: These preliminary data demonstrate afamitresgene autoleucel is efficacious and well tolerated in heavily pre-treated pts. Objective responses are reported across a wide range of MAGE-A4 antigen levels and deep responses have been observed. Initial durability data is encouraging. Preliminary response data in SPEARHEAD-1 is comparable to the findings of the prior Phase 1 trial [1]. To date, the safety profile of afamitresgene autoleucel has been favorable, with mainly low-grade cytokine release syndrome and tolerable/reversible hematologic toxicities. [1]. Van Tine BA, et al. CTOS; November 18-21, 2020; Virtual. Clinical trial information: NCT04044768.

11503 Background: EHE is a rare vascular cancer arising in liver, lung, soft tissue and bone. The natural history of metastatic disease varies considerably from indolent growth over years to rapid growth with fatal outcome in months. Treatment of patients (pts) with metastatic EHE with antiangiogenic therapy induces tumor response in a minority of pts, and median PFS is 6-12 months. TAZ-CAMTA1 translocation results in activation of MAPK pathway and is an oncogenic driver in EHE. We sought to evaluate the effect of MEK inhibition using trametinib in pts with unresectable EHE. Methods: A phase 2 trial of trametinib 2 mg daily was conducted in pts with EHE though the Experimental Therapeutics Clinical Trials Network supported by NCI in collaboration with SARC. Additional support was provided by the EHE Rare Cancer Charity and the EHE Foundation. Pts had to have evidence of objective tumor progression or EHE-related pain requiring narcotics for relief prior to enrollment. Presence of TAZ-CAMTA1 translocation was analyzed by fusion-FISH after enrollment. Primary trial endpoint was objective response rate (ORR) per RECIST1.1 with at least 1 objective response required in the 1st 13 pts to expand enrollment to 27. The trial was amended after stage 1 to continue enrollment to 27 pts with TAZ-CAMTA1 detected by FISH with goal of >4 objective responses in this group. Secondary objectives were PFS and OS rates, safety and change in pt-reported global health and pain scores per PROMIS questionnaires. Results: 43 pts were enrolled between 6/2017 – 9/2020 across 10 sites and 41 started therapy. TAZ-CAMTA1 fusion was detected in 26, not detected in 7, test failed in 5 and was not performed due to insufficient tumor in 5. Median pt age was 54 (range 22-81 yrs) and 11 were >65 yrs; 25 were female; ECOG was 0 in 23, 1 in 16 and 2 in 3 pts. Most pts experienced reduction in tumor size. ORR per RECIST was 7% (3/41); in pts with TAZ-CAMTA1 detected, the ORR was 0% (0/26). Mean pain intensity and interference scores had a statistically significant improvement and global quality of life scores did not statistically change after 4 weeks of therapy. 17 pts remained on treatment > 6 months and 7 > 12 months. 25 pts stopped trametinib due to EHE progression, 6 died during treatment, 6 withdrew from treatment, 3 stopped drug due to adverse event and 1 is on treatment. The most common AEs related to trametinib were rash, fatigue, nausea/vomiting, diarrhea, alopecia and edema; Grade >3 AEs included anemia, dyspnea, hypoxia, hypotension, syncope and dermatitis. Conclusions: To our knowledge, this is the largest prospective clinical study focused on pts with EHE. Although the trial did not meet the ORR goal, stable disease > 6 months was seen in 40% of pts, and EHE-related pain improved on treatment. Trametinib was associated with expected cutaneous and GI adverse effects. Additional pt-reported outcomes and biomarkers of inflammation are undergoing analysis. Clinical trial information: NCT03148275.

TPS2661 Background: Letetresgene autoleucel (lete-cel; GSK3377794) is an autologous T-cell therapy using a genetically modified T-cell receptor (TCR) to improve recognition of cancer cells expressing NY-ESO-1/LAGE-1a. Next generation NY-ESO-1 TCR T-cell therapies, such as GSK3901961 and GSK3845097, integrate added genetic modifications to enhance anticancer activity. GSK3901961 co-expresses the CD8α chain to stabilize TCR-human leukocyte A (HLA) class I interactions on CD4+ T cells, improving T-cell persistence and helper functions such as Type 1 T-helper antitumor responses. GSK3845097 co-expresses a dominant negative transforming growth factor-β (TGF-β) type II receptor to reduce TGF-β pathway activation and maintain T-cell proliferation, cytokine production, and cytotoxicity in the tumor microenvironment. A first-time-in-human master protocol (NCT04526509) will evaluate safety, tolerability, and recommended phase 2 dose (RP2D) of these and possible subsequent therapies. Substudy 1 will assess GSK3901961 in patients (pts) with advanced non-small cell lung cancer (NSCLC) or synovial sarcoma (SS). Substudy 2 will assess GSK3845097 in pts with advanced SS. Methods: Each substudy includes a dose confirmation stage to assess RP2D and a dose expansion stage. Key inclusion criteria are age ≥18 y; measurable disease per RECIST v1.1; HLA-A*02:01, A*02:05, or A*02:06 positivity; NY-ESO-1/LAGE-1a tumor expression; advanced (metastatic/unresectable) SS with t(X;18) translocation and anthracycline-based therapy receipt/completion/intolerance (SS only); and Stage IV NSCLC, receipt of ≥1 prior line(s) of standard of care (SOC) therapy including programmed death receptor- or ligand-1 inhibitors, and SOC chemotherapy receipt/intolerance (Substudy 1 only). Key exclusion criteria are prior malignancy that is not in complete remission or clinically significant systemic illness; prior receipt of gene/NY-ESO-1–specific therapy or allogenic stem cell/solid organ transplant; central nervous system metastases (SS only); and actionable genetic aberration and receipt/failure of ≥3 systemic therapy lines (Substudy 1 only). Primary endpoints are safety (adverse events) and tolerability (dose-limiting toxicities). Secondary endpoints include investigator-assessed overall response rate, duration of response, and maximum expansion/persistence and phenotype of infiltrating transduced T cells. Exploratory endpoints include laboratory parameters, overall survival, and anti-GSK3901961 or -GSK3845097 titers as applicable. Analyses will be descriptive. The substudies are enrolling. Funding: GSK (209012; NCT04526509). Editorial support was provided by Eithne Maguire, PhD, of Fishawack Indicia, part of Fishawack Health; funded by GSK. Previously presented at AACR 2021 (CT219). Clinical trial information: NCT04526509.

Imatinib is used to treat several haematological and solid malignancies. Cutaneous side effects could often limit the use of this medication. We present a case of a 62-year-old woman with a history of a gastrointestinal stromal tumour that developed a delayed cutaneous adverse reaction 10 days after starting imatinib 400 mg daily. She developed the same symptoms with reintroduction at a dose of 100 mg and with an alternative tyrosine kinase inhibitor, nilotinib 50 mg/day. Given that imatinib was considered her best treatment, she underwent a long induction of drug tolerance (IDT) protocol to imatinib. Patient tolerated the medication without further reactions for 6 months and had improvement of her cancer per last imaging studies. IDT should be considered in delayed hypersensitivity reactions to imatinib after a failed reintroduction of the drug or when no other equally effective agents are available.

Abstract Trial Information Click here to access other published clinical trials. 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.

Although checkpoint inhibitors have been approved in multiple cancers, they are still under investigation in soft tissue sarcoma (STS). We conducted a retrospective review to report the safety, efficacy, and prognostic factors related to checkpoint inhibitors in STS. A sequential cohort of metastatic STS patients from four institutions treated with checkpoint inhibitors was assembled. Logistic and Cox regression models were applied to determine the effect of patient characteristics, prior treatment, and baseline factors on achieving the best overall response of complete response (CR), partial response (PR), or stable disease (SD) as determined by the treating physician. Eighty-eight patients with two median prior therapies received checkpoint inhibitors. Treatments included pembrolizumab in 47, nivolumab in 6, ipilimumab in 1, combination ipilimumab/nivolumab in 27, and other combination immunotherapies in 7 patients. Immunotherapy was discontinued in 54 patients—72.2% for progression, 16.7% for toxicity, and 11.1% for other reasons. Median progression-free survival (PFS) was 4.1 months and median overall survival was 19.1 months. One patient with undifferentiated pleomorphic sarcoma (UPS) achieved a CR, while 20 patients had a PR, including 7 UPS, 9 leiomyosarcoma (LMS), and 1 each with alveolar soft part sarcoma, fibroblastic sarcoma, sclerosing epithelioid fibrosarcoma, and myxofibrosarcoma. Forty-five percent (9 of 20) of LMS patients achieved a PR. Twenty-eight patients had SD. Our results confirm the activity and safety of anti-PD-1 therapy in metastatic STS. A notable response rate was observed in UPS and LMS subtypes. This study expands the knowledge base beyond what is currently available from clinical trials involving checkpoint inhibitors in metastatic STS.

TPS11570 Background: Soft tissue sarcoma (STS) is a heterogenous malignancy of mesenchymal origin and includes more than 50 biologically distinct subtypes. Leiomyosarcoma (LMS), a neoplasm of smooth muscle origin, represents up to 20% of STS. The uterus is the most common site of origin in women. Advanced uterine LMS (uLMS) is initially treated with gemcitabine + docetaxel or anthracycline-based chemotherapy but overall survival remains < 24 mos. Besides recurrent alterations in RB1, TP53 and ATRX, insight into cancer biology of uLMS remains limited. Recently, whole exome and transcriptomic sequencing studies suggest uLMS harbors characteristic defects in the homologous recombination (HR) DNA repair pathway and thus features of BRCAness. HR-deficient cancers are unable to efficiently repair double-stranded DNA breaks and appear sensitive to treatment with poly ADP-ribose polymerase (PARP) inhibitors. In preclinical studies, the combination of temozolomide (T), an alkylating agent, and olaparib (O), a PARP inhibitor, was synergistic and markedly suppressed proliferation of uLMS models. A recent phase II study in small cell lung cancer defined the RP2D for T + O where the chief toxicity was myelosuppression. Methods: NCI Protocol #10250 is a single-arm, open-label, multi-center phase II clinical trial of T + O in patients with advanced uLMS. Eligible pts have ECOG PS ≤ 2, progression on ≥ 1 prior line of therapy and disease measurable by RECIST v1.1 and amenable to image-guided biopsy. Pts receive T 75 mg/m2 PO daily + O 200 mg PO BID on days 1-7 in 21-day cycles. The 1° endpoint is objective response rate (ORR). A one-stage binomial design is used to evaluate for an ORR ≤ 10% (null hypothesis) versus ≥ 35% (alternative hypothesis). The design calls for 22 patients. If 5/22 respond, the treatment is promising. This design yields 93% power and 1-sided type I error of 6%. 2° endpoints include progression free survival and safety. All pts undergo tumor biopsies pre-treatment and during cycle 2. Tissue is used for correlative analysis interrogating uLMS for features of BRCAness through (a) whole exome sequencing/RNAseq to evaluate for alterations in HR pathway component genes, (b) RAD51 foci formation by immunohistochemistry as a functional marker of HR pathway activity and (c) protein expression of Schlafen family member number 11 (SLFN11), an emerging biomarker for PARPi. Tumors are also evaluated for MGMT protein expression, a known determinant of sensitivity to T. The study opened to accrual 10/2019. Clinical trial information: NCT03880019.

11564 Background: Epithelioid sarcoma (ES) is a rare, aggressive soft tissue sarcoma characterized by loss of inhibitor of integrase 1 (INI1), allowing enhancer of zeste homologue 2 (EZH2) to repress cell differentiation and promote tumorigenesis. Tazemetostat (TAZ) is a selective inhibitor of EZH2 approved by the FDA for treatment of patients (pts) aged ≥16 years with metastatic or locally advanced ES ineligible for complete resection. Methods: This open-label, multicenter, multi-cohort phase 2 study (NCT02601950) evaluated safety and efficacy of TAZ in pts with INI1-negative tumors. ES pts were enrolled in Cohorts 5 and 6; pts in Cohort 6 underwent mandatory pre-dose (at screening) and post-dose biopsies (at Day 1 of cycle 2). Herein, we report the interim efficacy and safety data from Cohort 6. Results: As of July 31 2019, 44 pts were enrolled into Cohort 6 and treated with TAZ 800 mg BID. The objective response rate (ORR) was 11.4%; 4 pts (9.1%) had a partial response and 1 pt (2.3%) had a complete response (Table). Another 17 pts (38.6%) had stable disease (SD). 18 pts had progressive disease; 13 of these pts remained on study beyond progression. Progression-free survival (PFS) and overall survival (OS) at 56 weeks were 19.4% and 59.4%, respectively. In a pooled posthoc analysis of 106 ES pts from Cohorts 5 (n = 62), and 6, ORR was 13.2%. Grade 3–4 adverse events (AEs) were reported in 16 pts (36.4%), most commonly anemia (6.8%; n = 3) and tumor pain (6.8%; n = 3). 3 pts (6.8%) experienced grade 3–4 treatment-related AEs. One pt discontinued study drug and there were no treatment-emergent dose reductions or treatment-related deaths. These safety data from Cohort 6 are consistent with previously reported data from Cohort 5. 19 paired biopsies were included for translational endpoint analyses. Preliminary RNA seq and pathway analyses are currently ongoing and updated data, including additional biomarker data will be presented. Conclusions: Consistent with previously reported data from the completed Cohort 5, TAZ demonstrated clinically meaningful, durable, single agent activity in ES pts. Efficacy data from Cohort 6 continue to mature with 8 patients still on treatment. TAZ was well tolerated with a low incidence of treatment related AEs. Clinical trial information: NCT02601950 . [Table: see text]