A Phase I/II Investigation of Safety and Efficacy of Nivolumab and nab-Sirolimus in Patients With a Variety of Tumors With Genetic Mutations in the mTOR Pathway

BACKGROUND/AIM

Advanced sarcoma has a poor prognosis. Dysregulation of the mammalian target of rapamycin (mTOR) occurs in various types of cancer. We aimed to determine the safety and efficacy of mTOR inhibitor nab-sirolimus when combined with the immune checkpoint inhibitor nivolumab.

PATIENTS AND METHODS

Previously treated patients ≥18 years with confirmed diagnosis of advanced sarcoma or tumor with mutations in the mTOR pathway were treated with 3 mg/kg nivolumab intravenously every 3 weeks; escalating doses of nab-sirolimus at 56, 75 or 100 mg/m² were administered intravenously on days 8 and 15 beginning in cycle 2. The primary aim was to determine the maximum-tolerated dose; we also determined disease control, objective response, progression-free survival, overall survival, and correlation between response using Immune-related Response Evaluation Criteria for Solid Tumors (irRECIST) versus RECIST v1.1.

RESULTS

The maximum-tolerated dose was 100 mg/m² There were two patients with partial response, 12 with stable disease and 11 with progressive disease. Median progression-free and overall survival were 12 and 47 weeks, respectively. The best responders (partial responses) were patients with undifferentiated pleomorphic sarcoma with loss of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), tuberous sclerosis complex 2 (TSC2) mutation and estrogen receptor-positive leiomyosarcoma. Treatment-related adverse events of grade 3 or more included thrombocytopenia, oral mucositis, rash, hyperlipidemia and increased serum alanine aminotransferase.

CONCLUSION

The data indicate that (i) treatment with nivolumab plus nab-sirolimus is safe with no unexpected adverse events; (ii) treatment outcome parameters were not improved by combining nivolumab with nab-sirolimus; and (iii) best responders were patients with undifferentiated pleomorphic sarcoma with PTEN loss and TSC2 mutation and estrogen receptor-positive leiomyosarcoma. Future direction in sarcoma research with nab-sirolimus will be biomarker-based (TSC1/2/mTOR, tumor mutational burden/mismatch repair deficiency etc.).

SAINT: A Phase I/Expanded Phase II Study Using Safe Amounts of Ipilimumab, Nivolumab and Trabectedin as First-Line Treatment of Advanced Soft Tissue Sarcoma

BACKGROUND

This Phase 1/2 study is based on the hypothesis that immune checkpoint inhibitors are more effective when given earlier in the course of the disease for advanced soft tissue sarcoma.

METHODS

Phase I endpoints-maximum tolerated dose in previously treated patients; Phase II endpoints-best response, progression free survival and overall survival and incidence of adverse events in previously untreated patients; Phase I treatments-escalating doses of trabectedin (1.0, 1.2, 1.5 mg/m²) as continuous intravenous infusion over 24 h every 3 weeks, 1 mg/kg of ipilimumab given intravenously every 12 weeks, and 3 mg/kg of nivolumab given intravenously every 2 weeks; Phase II treatments-maximum tolerated dose of trabectedin and defined doses of ipilimumab and nivolumab.

RESULTS

Phase I (n = 9)-the maximum tolerated dose of trabectedin was 1.2 mg/m²; Phase II (n = 79)-6 complete responses, 14 partial responses, 49 stable disease, 25.3% best response rate, 87.3% disease control rate; median progression-free survival, 6.7 months (CI 95%: 4.4-7.9), median overall survival, 24.6 months (CI 95%: 17.0-.); Grade 3/4 therapy-related adverse events (n = 92)-increased ALT (25%), fatigue (8.7%), increased AST (8.7%), decreased neutrophil count (5.4%) and anemia (4.6%).

CONCLUSION

SAINT is a safe and effective first-line treatment for advanced soft tissue sarcoma.

Abstract CT235: MANTRA: A randomized, multicenter, phase 3 study of the MDM2 inhibitor milademetan versus trabectedin in patients with de-differentiated liposarcomas

Background: Murine double minute 2 (MDM2) is a negative regulator of tumor suppressor protein p53. MDM2 induces degradation of p53 and promotes tumorigenesis. MDM2 amplification occurs in many cancers but is documented in up to 100% of well-differentiated or de-differentiated liposarcomas (WD/DDLPS) [Cancer Genome Atlas Research Network. Cell 2017]. Inhibition of the MDM2-p53 interaction is a promising therapeutic approach to restore p53 tumor suppressor activity in WD/DDLPS. Milademetan (RAIN-32) is a small-molecule MDM2 inhibitor that inhibits the MDM2-p53 interaction and restores p53 function at nanomolar concentrations. In a phase 1 study, milademetan showed promising efficacy in 53 patients with WD/DDLPS when administered on an intermittent schedule (260 mg QD on Days 1-3 and 15-17 on a 28-day cycle), with a median progression-free survival (PFS) of 7.4 months [Gounder et al. AACR-NCI-EORTC 2020]. WD/DDLS are relatively resistant to chemotherapy, and systemic treatment options for patients with advanced disease are limited. MANTRA (RAIN-3201) is a randomized, multicenter, open-label, phase 3 registration study designed to evaluate the efficacy and safety of milademetan versus trabectedin in patients with unresectable or metastatic DDLPS with disease progression on ≥1 prior systemic therapies.

Methods: Eligible patients are ≥18 years of age with histologically confirmed unresectable and/or metastatic DDLPS, with or without a WD component, who have received ≥1 prior systemic therapies, including ≥1 anthracycline-based regimen, with radiographic evidence of progression by RECIST v1.1 within 6 months before study entry. Prior treatment with trabectedin or an MDM2 inhibitor is not permitted. Patients will be randomly assigned (1:1) to receive milademetan (260 mg once daily orally Days 1-3 and 15-17 on a 28-day cycle) or trabectedin (1.5 mg/m2 as a 24-hour intravenous infusion every 3 weeks). Randomization is stratified by Eastern Cooperative Oncology Group performance status (0 or 1) and number of prior treatments for WD/DDLPS (≤2 or >2). Tumor response will be evaluated by RECIST v1.1 at Weeks 8, 16, 24, and 32, and then every 12 weeks. Primary endpoint: PFS by blinded independent central review. Secondary endpoints: overall survival; disease control rate; objective response rate; duration of response; PFS by investigator assessment; safety; health-related quality of life. Exploratory endpoints: molecular markers in peripheral blood and/or tumor tissue; milademetan pharmacokinetics. To demonstrate a 3-month increase in PFS (from 3 to 6 months) corresponding to a hazard ratio of 0.5, approximately 160 patients will be required to observe 105 events with 93.9% power and 2-sided significance level of 5%. ClinicalTrials.gov: NCT04979442.

Citation Format: Mrinal M. Gounder, Gary K. Schwartz, Robin L. Jones, Sant P. Chawla, Victoria S. Chua-Alcala, Silvia Stacchiotti, Andrew J. Wagner, Gregory M. Cote, Robert G. Maki, Hanna Kosela-Paterczyk, Dale R. Shepard, Naisargee Shah, Richard Bryce, Robert C. Doebele, Shreyaskumar Patel. MANTRA: A randomized, multicenter, phase 3 study of the MDM2 inhibitor milademetan versus trabectedin in patients with de-differentiated liposarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT235.

Preliminary analysis of a phase I study of SNK01 (Autologous Non-genetically Modified Natural Killer Cells With Enhanced Cytotoxicity) monotherapy in patients with advanced solid tumors

2644

Background: Natural killer (NK) cells play a key role as the main effector cells toward cancer in innate immunity. Thus, a leading approach is to boost NK-cell mediated anti-tumor activity using adoptive transfer of ex vivo activated NK cells. NK cells have always been challenging to grow ex vivo especially when derived from heavily pretreated donors, thus most have focused on universal allogenic donor derived products. SNK01 is a first-in-kind, autologous non-genetically modified NK cell product with significant anti-tumor cytotoxicity and over 90% expression of CD16, NKG2D, NKp46, and DNAM-1, that can be consistently produced even from heavily pre-treated cancer patients (pts). While most if not all NK cell therapy has focused on liquid malignancies, SNK01 has been found to have strong activity against both liquid and solid tumors preclinically. We hypothesized that SNK01 would be safe without need for lymphodepletion and may demonstrate activity against heavily pre-treated solid tumors. Methods: In this Phase 1 dose escalation study (NCT03941262), SNK01 was administered intravenously (IV) weekly for 5 consecutive weeks using a 3+3 design in pts with advanced solid tumors. The starting dose was 1 x 109SNK01 cells and the highest dose was 4 x 109 SNK01 cells. Primary endpoint was safety based on AEs, vitals, laboratory tests, and PEs. Individual NK cell expansion was characterized for increases in cytotoxicity and changes in activating receptor expression. Results: As of Feb 1, 2022, 10 pts with advanced refractory solid tumors have been enrolled. Median age is 50 (range 32 – 75) and 6 were male. Pts had a median 5.5 lines of prior therapy (range 2-10). The subtypes were 4 leiomyosarcoma, 1 chondrosarcoma, 1 NSCLC, 1 small round cell tumor, 1 colorectal, 1 synovial cell sarcoma, 1 angiosarcoma. NK cells were successfully activated and expanded, even from heavily pre-treated pts. Average cytotoxicity was increased over 400% and average activating receptor expression was greater than 90%. There were only two Grade 1 adverse events reported in the 50 total doses given. Best objective response of SD was demonstrated in 7 pts. Of patients who progressed in the dose escalation cohorts, several reported an overall improvement in their QOL. Based on this improvement, patients then became eligible to be treated with additional salvage chemotherapy to which some then showed additional response. Conclusions: SNK01 with high cytotoxicity and activating receptor expression can be consistently produced from heavily pretreated patients. SNK01 was very safe and appears to have some clinical activity against heavily pretreated solid tumors and may even sensitize tumors to additional chemotherapy. SNK01 will be studied further as monotherapy and in various combination regimens. Clinical trial information: NCT03941262.

Five-year results of a phase 2 trial using ipilimumab (I), nivolumab (N), and trabectedin (T) for previously untreated advanced soft tissue sarcoma (NCT03138161)

11573

Background: Understanding the bifunctional role that the immune system plays in tumor eradication vs growth promotion is critical in the design and timing of tumoricidal and immunologic therapies for sarcomas. Hypothesis: Immune checkpoint inhibitors that promote sustained T cell activation would be most effective when given as first line therapy, together with a tumoricidal agent. Methods: Eligible patients for this Phase 2 study are males or females ≥ 18 years of age with locally advanced unresectable or metastatic soft tissue sarcoma, previously untreated, with measurable disease by RECIST v1.1. Treatment protocol: (I) mg/kg i.v. q 12 wks, (N) 3 mg/kg i.v. q 2 wks, (T) 1.2 mg/m2 CIV q 3 wks. Treatment Outcome Parameters: (1) Best objective response rate by RECIST v1.1, (2) Progression-free survival (PFS), (3) Overall survival (OS), and (4) Incidence of treatment-related adverse events. Results: Ninety-nine patients were enrolled. Efficacy analysis (n = 88): There were 8CR (1 surgical CR), 11PR, 58SD, 11PD. Overall response rate was 21.6%, Disease Control Rate, 87.5%. The median PFS was 7 (range:1-44) months, median OS, 14 (range: 1-46) months. Grade 3 TRAEs include fatigue (n = 8), adrenal insufficiency (n = 1), dehydration (n = 1), hyponatremia (n = 2), increased AST (n = 8), increased ALT (n = 24), increased ALP (n = 2), port site infection (n = 2), psoriasis exacerbation (n = 1), anemia (n = 9), thrombocytopenia (n = 2), and neutropenia (n = 5). Grade 4 TRAES include anemia (n = 1), neutropenia (n = 1), thrombocytopenia (n = 2), increased AST (n = 2), increased ALT (n = 2), and increased CPK (n = 2). Grade 5 TRAES include rhabdomyolysis (n = 1). There was no incidence of alopecia nor cardiac toxicity reported. Conclusions: Taken together, these data indicate that first-line combinatorial therapy with Ipilimumab, Nivolumab, and Trabectedin (1) may be more effective than standard first line therapy (doxorubicin/ifosfamide/mesna), and (2) is safer than standard first line therapy for advanced soft tissue sarcoma. Clinical trial information: NCT03138161.

Interim analysis of a phase I study of SNK01 (Autologous Nongenetically Modified Natural Killer Cells with Enhanced Cytotoxicity) and avelumab in advanced refractory sarcoma

11517

Background: For patients (pts) with advanced sarcomas in the relapsed/refractory setting, there are very few if any effective salvage treatment options. The likelihood of response and/or tumor control only diminishes with each subsequent line of therapy. Monotherapy of PD-L1 inhibitors has shown modest to no activity in most sarcomas, especially in tumors that have little to no PD-L1 expression. Natural killer (NK) cells have recently been implicated in the antitumor response to immune checkpoint inhibitors with some evidence suggesting a role in PD-L1 negative tumors. SNK01 is a first-in-kind, autologous nongenetically modified NK cell therapy with highly enhanced cytotoxicity and over 90% activating receptor expression which can be consistently produced from heavily pretreated pts. Avelumab is an anti-PD-L1 immunotherapy with dual engagement of both the adaptive and innate immune systems. We hypothesized that this combination would be safe, and together better overcome the immunosuppressive tumor microenvironment. Methods: In this Phase I study (NCT03941262), cohort 4 is comprised of up to 18 pts treated with 800 mg of avelumab + 4 x 109 SNK01 cells every two weeks via IV Infusion. Pts were eligible regardless of PD-L1 status and permitted to continue treatment indefinitely until progression or unacceptable toxicity. The primary endpoint is safety. The secondary endpoints include overall response rate (ORR), progression free survival (PFS), and overall survival (OS). Results: As of February 1, 2022, 15 pts with advanced refractory sarcoma have been enrolled. Median age is 50 (range 20-75) and 8 were male. Pts had a median of 5 lines of prior therapy (range 1-8). The subtypes included 6 leiomyosarcoma, 2 osteosarcoma, 1 pleomorphic liposarcoma, 1 Ewing’s sarcoma, 1 epithelioid sarcoma, 1 epithelioid mesothelioma, 1 endometrial stromal sarcoma, and 1 sarcoma NOS. There were three Grade 2 or 3 adverse events related to avelumab, but unrelated to SNK01. Best objective response by RECIST 1.1 was PR in 2 pts (ORR of 13.3%) and SD in 3 pts. Median PFS is 11.14 weeks. Several pts had PD-L1 negative disease and response appears to be independent of PD-L1 status. Of pts who progressed in this cohort, several reported an overall improvement in their QoL and some pts became eligible to be treated with additional salvage chemotherapy, resulting in some additional clinical response. Conclusions: SNK01 combined with avelumab was safe and well tolerated and appears to have some clinical activity against several types of heavily pretreated advanced sarcoma, independent of PD-L1 status. It may also keep rapidly progressing disease stable enough to allow additional cytotoxic chemotherapy. A proposed study expansion is planned. Clinical trial information: NCT03941262.

Two year results of blessed: Expanded access for deltarex-g for an intermediate size population with advanced pancreatic cancer and sarcoma (NCT04091295) and individual use IND for EARLY-STAGE invasive carcinoma of breast (IND# 19130)

e15048

Background: Defects in cell cycle control are fundamental oncogenic drivers and targeting deregulated cell cycling is under intensive study. Cell cycle cyclin G1 (CCNG1) inhibitor therapy, exemplified by DeltaRex-G, a tumor-targeted retro vector encoding a cytocidal CCNG1 inhibitor gene, has been tested in over 280 cancer patients worldwide in early studies, inducing long term (10-13 years) survival in certain patients with intractable metastatic pancreatic adenocarcinoma, sarcoma, and breast cancer. Hence, further clinical development of DeltaRex-G for cancer patients who have few or no therapeutic options is apropos. Methods: Primary objective: To determine overall survival. Secondary objective: To evaluate disease control, best overall response, and incidence of treatment-related adverse events. Patient and Methods: Study 1 is entitled “Blessed: Expanded Access for DeltaRex-G for Advanced Pancreatic Cancer and Sarcoma (NCT04091295)”. Study 2 is entitled “Compassionate Use of DeltaRex-G for Advanced Cancers. In both studies, patients will receive DeltaRex-G at 1-3 x 10e11 cfu i.v. over 15-30 minutes, 3 x a week until significant disease progression or unacceptable toxicity occurs. Results: Seventeen patients were enrolled, 9 sarcomas, 2 pancreatic adenocarcinomas, 1 non-small cell lung cancer, 2 breast carcinoma, 1 prostate cancer, 1 cholangiocarcinoma, and 1 basal cell carcinoma and actinic keratosis. Three patients were enrolled in Study 1 and 14 patients were enrolled in Study 2. Two patients were initially enrolled in Study 1 and later enrolled in Study 2. Twelve of 17 enrolled patients were treated with DeltaRex-G monotherapy or in combination with FDA-approved cancer therapies. Of the 12 treated patients, 5 are alive 10 to 30 months from DeltaRex-G treatment initiation. Two patients with early-stage triple receptor-positive and triple receptor-negative breast cancer who received DeltaRex-G as adjuvant/first-line therapy are alive one year in complete remission; 2 patients with chemo-resistant Stage 4 sarcoma are alive 2 1/2 years, and one patient with advanced basal cell carcinoma is alive 10 months from treatment initiation. There were no treatment-related adverse events reported. Conclusions: Taken together,the data suggest that (1) Adjuvant/first-line therapy with DeltaRex-G may reduce the incidence of recurrence of early-stage invasive carcinoma of the breast and (2) DeltaRex-G may evoke tumor growth stabilization after failing standard chemotherapy. Phase 2 studies are planned to evaluate if DeltaRex-G (1) will reduce the incidence of recurrence in early-stage invasive carcinoma of breast, (2) improve survival in pancreatic cancer, and (3) prolong progression-free survival and overall survival in advanced sarcoma. Clinical trial information: NCT04091295.

GALLANT: A phase 2 study using metronomic gemcitabine, doxorubicin, nivolumab, and docetaxel as second/third-line therapy for advanced sarcoma (NCT04535713)

11518

Background: In our experience, combinatorial therapy with lower doses of doxorubicin, gemcitabine, and docetaxel has been effective with a manageable toxicity profile in patients with advanced soft tissue sarcomas. Hypothesis: The addition of nivolumab will have synergistic effects and improve treatment outcomes. Methods: Primary objective: To assess progression-free survival; Secondary objectives: (1) To evaluate best overall response during treatment period confirmed in a 6-week follow-up, (2) PFS rate at 6 and 9 months, (3) Overall survival rate at 6, 12 months, and (4) Incidence of treatment-related adverse events (TRAEs). Inclusion criteria: Previously treated male and female subjects, > 18 years of age, pathologically confirmed diagnosis of locally advanced, unresectable, or metastatic sarcoma, measurable disease by RECIST v1.1, and acceptable hematologic and organ functions. Exclusion Criteria: History of autoimmune disorder. Treatment schedule: Metronomic doses of gemcitabine (600 mg/m2 max:1000 mg), doxorubicin (18 mg/m2; max: 32 mg), docetaxel (25 mg/m2; max:42 mg) on Day 1 and Day 8, and nivolumab (240 mg) on Day 1 only. Repeat treatment cycles may be given every three weeks if toxicity grade is <1. Results: This is an Interim Report on the modified Intent-to-treat population (n = 43). This population completed at least one treatment cycle and had a follow-up CT or MRI scan at week 6. The most common histological subtypes in this group include leiomyosarcoma (n = 15), pleomorphic sarcoma (n = 4), synovial sarcoma (n = 4), liposarcoma (n = 3), osteosarcoma (n = 3) and other (n = 10). Best Overall Response = 2 CR (surgical CR), 6 PR, 30 SD, 5 PD. The disease control rate (CR+PR+SD) was 88.4%. Median PFS was > 4.6 (range: 1-27) months; 4 month PFS rate 60%. Median OS 6.2 months, with 4-month OS 74%. Historically, the median PFS on preceding lines of therapy was 2 (range: 1-14) months. There were no unexpected side effects noted in this study. The most common grade 3/4 TRAEs include Fatigue (n = 13), Nausea (n = 9), Neutropenia (n = 8), thrombocytopenia (n = 6), Anemia (n = 6). Conclusions: The GALLANT protocol using metronomic Gemcitabine, Doxorubicin (Adriamycin), Nivolumab, and Docetaxel (Taxotere) (1) is an effective regimen as second/third-line therapy for advanced sarcoma with no unexpected side effects, and (2) may have synergistic activity when this metronomic chemotherapy is combined with an immune checkpoint inhibitor. Clinical trial information: NCT04535713.

TTI-621-03: A phase I/II study of TTI-621 in combination with doxorubicin in patients with unresectable or metastatic high-grade leiomyosarcoma (LMS)

TPS11593

Background: Doxorubicin is a standard of care agent for patients with advanced soft tissue sarcoma, with a response rate of around 15%, progression-free survival of 5-7 months and cumulative cardiac toxicity that limits its use. TTI-621 is a recombinant soluble fusion protein that combines the N-terminal portion of human SIRPα (the binding domain for CD47) with the Fc region of human IgG1, generating a decoy receptor for CD47 on the surface of tumor cells that both over-rides CD47-mediated inhibition of phagocytosis and provides a pro-phagocytic stimulation. Many solid tumors express high levels of CD47 which is associated with poor prognosis, thought to be the result of CD47-mediated inhibition of macrophage phagocytosis and escape of immune-mediated clearance. Interruption of the CD47-SIRPα signaling pathway using monoclonal antibodies to CD47 has shown anti-tumor activity in animal models and in some early clinical trials. The combination of doxorubicin with CD47-targeted antibodies results in enhanced anti-tumor activity and increased macrophage-mediated cell killing in animal models and macrophage-mediated phagocytosis of cancer cell lines in vitro, suggesting that combining TTI-621 with doxorubicin might be more effective than doxorubicin alone in tumor types that express CD47 and have high numbers of macrophages, such as LMS. Thus, a Phase 1/2 study was initiated to evaluate this combination in patients with advanced soft tissue sarcoma, including LMS. Methods: TTI-621-03 is a Phase 1/2, open-label study of TTI-621 in combination with doxorubicin in patients with anthracycline-naïve disease. The Phase 1 dose escalation evaluates doses of TTI-621 (0.2 to 2.0 mg/kg) in combination with doxorubicin at 75 mg/m2 in patients with high-grade soft tissue sarcomas. Expansion cohorts will evaluate TTI-621 (0.2 and 2.0 mg/kg) with doxorubicin in patients with LMS, with pathology confirmed at a central laboratory. The primary goals of this study are evaluation of safety of TTI-621 administered in combination with standard-of-care doxorubicin and to further evaluate clinical activity (ORR, PFS, OS), safety, PK and patient-reported quality of life in the LMS subpopulation. The dose escalation portion of the study has been completed without DLT. Enrollment to the expansion portion of the study is underway. Clinical trial information: NCT04996004.

MANTRA: A randomized, multicenter, phase 3 study of the MDM2 inhibitor milademetan versus trabectedin in patients with de-differentiated liposarcomas

TPS11589

Background: Murine double minute 2 (MDM2) is a negative regulator of tumor suppressor protein p53. MDM2 induces degradation of p53 and promotes tumorigenesis. MDM2 amplification occurs in many cancers but is documented in up to 100% of well-differentiated or dedifferentiated liposarcomas (WD/DDLPS) [Cancer Genome Atlas Research Network. Cell 2017]. Inhibition of the MDM2-p53 interaction is a promising therapeutic approach to restore p53 tumor suppressor activity in WD/DDLPS. Milademetan (RAIN-32) is a small-molecule MDM2 inhibitor that inhibits the MDM2-p53 interaction and restores p53 function at nanomolar concentrations. In a phase 1 study, milademetan showed promising efficacy in 53 patients with WD/DDLPS when administered on an intermittent schedule (260 mg QD on Days 1–3 and 15–17 on a 28-day cycle), with a median progression-free survival (PFS) of 7.4 months [Gounder et al. AACR-NCI-EORTC 2020]. WD/DDLS are relatively resistant to chemotherapy, and systemic treatment options for patients with advanced disease are limited. MANTRA (RAIN-3201) is a randomized, multicenter, open-label, phase 3 registration study designed to evaluate the efficacy and safety of milademetan versus trabectedin in patients with unresectable or metastatic DDLPS with disease progression on ≥ 1 prior systemic therapies. Methods: Eligible patients are ≥ 18 years of age with histologically confirmed unresectable and/or metastatic DDLPS, with or without a WD component, who have received ≥ 1 prior systemic therapies, including ≥ 1 anthracycline-based regimen, with radiographic evidence of progression by RECIST v1.1 within 6 months before study entry. Prior treatment with trabectedin or an MDM2 inhibitor is not permitted. Patients will be randomly assigned (1:1) to receive milademetan (260 mg once daily orally Days 1–3 and 15–17 on a 28-day cycle) or trabectedin (1.5 mg/m2 as a 24-hour intravenous infusion every 3 weeks). Randomization is stratified by Eastern Cooperative Oncology Group performance status (0 or 1) and number of prior treatments for WD/DDLPS (≤ 2 or > 2). Tumor response will be evaluated by RECIST v1.1 at Weeks 8, 16, 24, and 32, and then every 12 weeks. Primary endpoint: PFS by blinded independent central review. Secondary endpoints: overall survival; disease control rate; objective response rate; duration of response; PFS by investigator assessment; safety; health-related quality of life. Exploratory endpoints: molecular markers in peripheral blood and/or tumor tissue; milademetan pharmacokinetics. To demonstrate a 3-month increase in PFS (from 3 to 6 months) corresponding to a hazard ratio of 0.5, approximately 160 patients will be required to observe 105 events with 93.9% power and 2-sided significance level of 5%. Clinical trial information: NCT04979442.

Preliminary efficacy from an ongoing phase 1 dose escalation study of seclidemstat (SP-2577) in patients (pts) with advanced solid tumors (AST)

3073

Background: Lysine-specific demethylase 1 (LSD1) is an epigenetic enzyme that is aberrantly expressed in many solid tumors. High levels of LSD1 expression are often correlated with poor patient prognosis due to LSD1’s role in cancer cell proliferation, metastasis, and chemoresistance. Seclidemstat is a novel, selective, reversible and oral LSD1 inhibitor capable of inhibiting both LSD1’s catalytic and scaffolding functions. We report preliminary efficacy in AST from an ongoing phase 1 trial. Methods: SALA-003-AC19 (NCT03895684) is a phase 1 trial of single agent SP-2577 in pts with AST. All pts had progressive disease (PD) at time of study entry. Pts received oral SP-2577 twice a day under fasting condition, in 28-day cycles (C). The primary objective is safety and tolerability. Secondary objectives are to determine maximum-tolerated dose, preliminary efficacy, pharmacokinetics, and pharmacodynamics. Results: As of December 30, 2020, 19 pts with AST (10 sarcoma, 2 prostate, 2 ovarian, 2 pancreatic, 1 renal, 1 cervical, 1 breast) were enrolled. Pts received escalating doses of SP-2577 from 150 to 600 mg BID and the dose escalation is ongoing. The median age was 63 years (range, 21–79). 42% were male, and pts had received a median of 4 (range, 1–8) prior systemic therapies. The most common (>5%) grade 3 treatment-related adverse events were GI related including diarrhea (5.3%) and abdominal pain (5.3%). No grade 4 events were reported and there were no treatment-related deaths. Safety data will be presented after completion of phase 1. Three pts had at least one dose reduction. Among the 13 pts who were evaluable for response at end of C2, 7 pts (54%) had best response of stable disease (SD) with median time to progression (TTP) of 4.3 months (range, 2.1–11.5). Four of the 7 pts had genetic abnormalities that may demonstrate increased sensitization to SP-2577 according to preclinical studies. Characteristics of 7 pts with SD at C2 and beyond are shown in the table. Conclusions: Seclidemstat has shown activity among advanced sarcoma pts with a manageable safety profile. The dose escalation is ongoing and preliminary clinical data supports further exploration in FET-translocated sarcoma as single agent and in combination therapy. Clinical trial information: NCT03895684. [Table: see text]

SAINT: Results of an expanded phase II study using safe amounts of ipilimumab (I), nivolumab (N), and trabectedin (T) as first-line treatment of advanced soft tissue sarcoma [NCT03138161]

11520

Background: Sarcoma cells are most immunogenic earlier in the disease. Hypothesis: Immune checkpoint inhibitors would be most effective when given as first-line therapy. Methods: Eligible patients include previously untreated male or female patients, ≥ 18 years of age with locally advanced unresectable or metastatic soft tissue sarcoma (STS), with measurable disease by RECIST v1.1. Immune checkpoint inhibitors I (1 mg/kg i.v. q 12 weeks) and N (3 mg/kg i.v. q 2 weeks) were given with T (1.2 mg/m2 i.v. q 3 weeks), a tumoricidal agent that depletes growth-promoting macrophages in the tumor microenvironment. Primary endpoint: Objective response rate by RECIST v1.1; Secondary endpoints: (1) Progression-free survival (PFS) at 6 months, (2) Overall survival (OS) at 6, 9, 12, 24, and 48 months, and (3) Incidence of adverse events. Results: Efficacy analysis: There were forty-one evaluable subjects. Best overall response rate was 19.5%; disease control rate 87.8%. The median OS was >12.5 months; median PFS was >6.0 months (6-month OS rate: 75%; 6-month PFS rate: 50%). Safety analysis: Grade 3 TRAEs include fatigue (n = 5), increased TSH (n = 3), decreased TSH (n = 1), adrenal insufficiency (n = 1), hyperglycemia (n = 1), dehydration (n = 1), hyponatremia (n = 2), bipedal edema (n = 2), increased AST (n = 8), increased ALT (n = 19), increased ALP (n = 2), increased CPK (n = 3), port site infection (n = 2), psoriasis exacerbation (n = 1), anemia (n = 6), thrombocytopenia (n = 2), and neutropenia (n = 2). Grade 4 TRAES include neutropenia (n = 1), thrombocytopenia (n = 2), and increased CPK (n = 2). Conclusions: These data suggest that combinatorial therapy with Ipilimumab, Nivolumab and Trabectedin (1) may have synergistic activity in achieving disease control, and (2) is safe with manageable toxicity for patients with previously untreated STS. Clinical trial information: NCT03138161 . [Table: see text]

A phase I/II investigation of nivolumab and ABI-009 (nab-sirolimus) in advanced undifferentiated pleomorphic sarcoma (UPS), liposarcoma (LPS), chondrosarcoma (CS), osteosarcoma (OS), and Ewing sarcoma: Preliminary efficacy and safety results

11057

Background: Immune checkpoint inhibitors that promote sustained T cell activation may have synergistic activity with an mTOR inhibitor. This phase 1/2 study is aimed to investigate if ABI-009 a novel albumin-bound mTOR inhibitor is feasible and improve clinical outcomes in combination with nivolumab. Methods: Eligible patients with advanced UPS, LPS, CS, OS, or Ewing sarcoma are treated with the standard dose of nivolumab (240 mg given IV every 3 weeks, Day 1 of every 21-day Cycle). ABI-009 will be given IV on Days 8 and 15 of each cycle starting on Cycle 2 following the 2nd nivolumab dose. Phase 1 portion is a dose-finding study using the 3+3 design. The starting dose of ABI-009 is 56 mg/m2, and sequentially escalating doses are 75 and 100 mg/m2. The primary endpoint is to identify the maximum-tolerated dose (MTD) of ABI-009 + nivolumab, secondary endpoints include disease control rate, progression-free survival (PFS), and overall survival (OS). Exploratory endpoints include correlation of PFS and OS with PD-L1 and other biomarkers. The Phase 2 part of study will enroll 31 additional patients to further assess efficacy and safety at the MTD. Results: 9 patients were treated in Phase 1 (n = 3 each dose level); 5/9 patients had OS, 3/9 CS, and 1 had Ewing sarcoma. No dose-limiting toxicities (DLTs) were observed, the MTD was not reached, and 100 mg/m2 ABI-009 was designated as the recommended phase 2 dose. Safety analysis: At Dose 1: Grade 3 treatment-related adverse events (TRAEs) included hyper dyslipidemia (n = 1), and hyperglycemia (n = 1). At Dose 2: Grade 3 TRAEs included increased ALT (n = 1). At Dose 3: Grade 3 TRAEs included hypophosphatemia (n = 1). Seven of 9 patients have discontinued treatment: 5 patients due to PD, 2 with SD opted to stop treatment due to drug-related Grade 2 AEs (pruritus, acneiform rash, and 2 with SD are still on therapy at Dose 3. The median PFS at dose level 3 has not yet been reached. Conclusions: The MTD was not reached and Dose 3 (100 mg/m2) has been designated as the phase 2 dose of ABI- 009, combinable with nivolumab. Enrollment to phase 2 is ongoing. Clinical trial information: NCT03190174.

SAINT: Results of a phase 1/2 study of safety/efficacy using safe amounts of ipilimumab, nivolumab, and trabectedin as first-line treatment of advanced soft tissue sarcoma

11016

Background: Sarcoma cells are most immunogenic earlier in the disease course and prior to treatment when the immune system can recognize and destroy them. Hypothesis: Immune checkpoint inhibitors would be most effective when given as first line therapy. Methods: This is an IRB-approved dose-seeking Phase 1/2 protocol using defined doses of I (1 mg/kg i.v. q 12 weeks), N (3 mg/kg i.v. q 2 weeks) and escalating doses of T (1.0, 1.2, 1.5 mg/m2 i.v. q 3 weeks), employing the “Cohort of Three” design, followed by a Phase 2 using the MTD of trabectedin. Results: Nine subjects were treated in Phase 1 of the study, and 31 subjects in Phase 2. Safety analysis: at Dose 1: Grade 3 treatment-related adverse events (TRAEs) included fatigue (n = 1), increased TSH (n = 1). At Dose 2, Grade 4 TRAEs included thrombocytopenia with bleeding, DLT (n = 1), increased CK (n = 1); Grade 3 TRAEs included anemia (n = 1), myalgia (n = 1), increased TSH (n = 1), decreased TSH (n = 1), increased AST (n = 1). Efficacy analysis (evaluable patients): At Dose 1: Disease Control Rate (DCR = CR, PR, SD) was 67%, median PFS, 18 weeks; median OS, 50 weeks; At Dose 2: PR (n-1), DCR 60%, median PFS, 24 weeks; median OS, > 46 weeks. At Phase 2, MTD Dose 2 (PUPs): Safety analysis (n = 31): Grade 3 TRAEs included fatigue (n = 2), increased ALT (n = 6), increased AST (n = 4), hypernatremia (n = 1), hyponatremia (n = 1), dehydration (n = 1), rash (n = 1), port cellulitis (n = 1), psoriasis exacerbation (n = 1), increased TSH (n = 1), decreased hemoglobin (n = 2), neutropenia (n = 1). Efficacy analysis (N = 23 evaluable): PR (n-5; 2 UPS, 1 synovial sarcoma, 1 liposarcoma, 1 leiomyosarcoma,), BORR 22%, DCR 96%. Median PFS and OS not yet reached. After 4 treatment cycles, one resected tumor showed 80% necrosis and a greater number (30%) of CD8+ killer T cells, in the TME compared to archived pre-treatment tumor. Conclusions: These data suggest that the SAINT protocol (1) is safe with manageable adverse events, with no additive toxicity, and (2) may control tumor growth. Phase 2 of the study is on-going. Clinical trial information: NCT03138161.

The SAINT: Initial results of a phase I/II study of safety/efficacy using safe amounts of ipilimumab, nivolumab, and trabectedin as first-line treatment of advanced soft tissue sarcoma

22

Background: Sarcoma cells are most immunogenic at the onset of cancer. Hypothesis: Immune checkpoint inhibitors would be most effective when given as first line therapy. Objectives: (1) To evaluate the safety of ipilimumab (I), a CTLA4 inhibitor, nivolumab (N), a PD-1 inhibitor, and escalating doses of trabectedin (T), a marine-derived natural alkaloid, in advanced soft tissue sarcomas (STS), (2) To investigate the BORR, DCR, PFS and OS, and (3) to correlate response with immune cell trafficking in the tumor microenvironment. Methods: This is an IRB-approved dose-seeking phase 1/2 study using defined doses of I (1 mg/kg IV q 12 weeks), N (3 mg/kg IV q 2 weeks) and escalating doses of T (1.0, 1.3, 1.5 mg/m2 IV q 3 weeks), employing “cohort of three” design, with a Phase 2 component using the MTD of T. Results: Phase 1 safety analysis: At Dose 1: Grade 3 treatment related adverse events (TRAEs): fatigue (n = 1), increased TSH (n = 1). At Dose 2, Grade 4 TRAEs: thrombocytopenia with bleeding, DLT (n = 1), increased CK (n = 1); Grade 3 TRAEs: anemia (n = 1), myalgia (n = 1), increased TSH (n = 1), decreased TSH (n = 1), increased AST (n = 1). At Phase 2, Grade 4 TRAEs: increased CK (n = 1); Grade 3 TRAEs: increased ALT (n = 4), anemia (n = 3) neutropenia (n = 1), portal cellulitis (n = 1). Efficacy analysis: Phase 1 (n = 9): At Dose 1: DCR 67%, median PFS, 18 weeks; median OS, 50 weeks; At Dose 2: PR (n-1, rhabdomyosarcoma), DCR 60%, median PFS, > 42 weeks; median OS, > 47 weeks. Phase 2 (n = 16): PR (n = 3; 1 liposarcoma, 1 leiomyosarcoma, 1UPS); BORR 18.75%, DCR 87.5%, median PFS, > 19 weeks; median OS, > 26 weeks. Surgical resection was undertaken in 1 patient with SD after 4 cycles. The surgical specimen showed 80% necrosis and greater number (30%) of CD8+ killer T cells, 10% PD-L1+ cells in the TME compared to that of archived pre-treatment tumor. Conclusions: Taken together, these data suggest that the SAINT protocol (1) is safe with manageable adverse events, with no additive toxicity, and (2) may control tumor growth. The phase 2 part of the study is on-going. Clinical trial information: NCT03138161.

Initial results of a phase III investigation of safety/efficacy of nivolumab and ABI-009 (nab-sirolimus) in advanced undifferentiated pleomorphic sarcoma (UPS), liposarcoma (LPS), chondrosarcoma (CS), osteosarcoma (OS), and Ewing sarcoma

21

Background: Objectives: (1) To investigate the MTD of ABI-009 when given with nivolumab, a PD-1 inhibitor, in previously treated advanced undifferentiated pleomorphic sarcoma, liposarcoma, chondrosarcoma, osteosarcoma and Ewing sarcoma; (2) To investigate the disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) of this combination therapy in the above mentioned patient group, and (3) To correlate PFS with PD-L1 and other biomarker expression in patients’ tumors. Methods: This is an IRB approved protocol with 2 parts. The Phase 1 part is a dose-finding study using the “cohort of three design”, wherein standard doses of nivolumab 240 mg is given iv every 3 weeks (Day 1 of every 21-day Cycle). ABI-009 will be given IV on Days 8 and 15 of each cycle starting on Cycle 2 following the 2nd nivolumab dose. The starting dose of ABI-009 is 56 mg/m2, and sequentially escalating doses are 75, and 100 mg/m2. The Phase 2 part of study will enroll 31 additional patients to further assess efficacy and safety at the MTD. Results: The Phase 1 part of study is closed, after 9 patients were treated successfully at 3 dose levels. No dose-limiting toxicities (DLTs) were observed, the MTD was not reached, and 100 mg/m2 ABI-009 was designated as the recommended phase 2 dose. Safety analysis: At Dose 1 (n=3): Grade 3 treatment-related adverse events (TRAEs) included hyperdyslipidemia (n=1), and hyperglycemia (n=1). At Dose 2 (n=3): Grade 3 TRAEs included increased ALT (n=1). At Dose 3 (n=3): Grade 3 TRAEs included hypophosphatemia (n=1). Seven of 9 patients have discontinued treatment: 5 patients due to PD, 2 with SD opted to stop treatment due to drug-related Grade 2 AEs (pruritus, acneiform rash, and 2 with SD are still on therapy at Dose 3. Conclusions: The primary objective has been met with no DLTs, the MTD was not reached and Dose 3 has been designated as the phase 2 dose of ABI-009 which is on-going. Clinical trial information: NCT03190174.

A phase 1b investigation of safety/efficacy of nivolumab and ABI-009 (nab-rapamycin) in advanced undifferentiated pleomorphic sarcoma (UPS), liposarcoma (LPS), chondrosarcoma (CS), osteosarcoma (OS) and Ewing sarcoma

TPS45

Background: Immune checkpoint inhibitors that promote sustained T cell activation may have synergistic activity with an mTOR inhibitor. Objectives: (1) To investigate the maximum tolerated dose of ABI-009, an mTOR inhibitor, when given sequentially with nivolumab, a PD-1 inhibitor, in advanced UPS, LPS, CS, OS and Ewing sarcoma; (2) To investigate the disease control rate (DCR), progression free survival (PFS), recurrence-free survival (RFS) and overall survival using nivolumab/ABI-009 combination therapy in advanced UPS, LPS, CS, OS and Ewing sarcoma; (3) To correlate disease control rate (DCR) based on Immune-related Response Criteria (irRECIST) with that based on RECIST v1.1, and to correlate PFS with PD-L1 and other biomarker expression in patients’ tumors. Methods: Forty to fifty previously treated patients with UPS, LPS, CS, OS or Ewing sarcoma will be enrolled. This is a phase 1b study using a defined dose of nivolumab 240 mg and escalating doses of ABI-009 56,75,100 mg/m2 given i.v. I. Dose Escalation Phase 1 Part of Study: The study will employ the standard “cohort of three” design. The maximum tolerated dose is defined as the highest safely tolerated dose, where not more than one patient experienced DLT, with the next higher dose level having at least two patients who experienced DLT. II. Expansion Phase 1b Part of Study: An additional 22-28 patients will receive ABI-009 at the MTD and defined doses of nivolumab to assess overall safety and potential efficacy in a greater number of patients. Patients in the expansion phase of the study may continue treatment until significant disease progression or unacceptable toxicity occurs. Statistical Considerations: Categorical variables will be summarized by the n and percent in each category. Point estimates for efficacy endpoint incidences will be accompanied by a 2-sided 95% exact binomial CI. Time to event endpoints will be summarized descriptively using the KM method. Clinical trial information: NCT03190174.

Phase 1/2 study of safety/efficacy using trabectedin, ipilimumab, and nivolumab as first-line treatment of advanced soft tissue sarcoma (STS)

TPS46

Background: Sarcoma cells are most immunogenic at the onset of cancer when the immune system can recognize and destroy them. Hence, immune checkpoint inhibitors would be most effective when given as first line therapy. Objectives: (1) To investigate the maximum tolerated dose of trabectedin, an alkylating agent, when given sequentially with ipilimumab, a CTLA4 inhibitor, and nivolumab, a PD-1 inhibitor, in advanced STS, (2) To investigate the objective response rate (ORR), progression free survival (PFS) and overall survival (OS) , and (3) To correlate PFS with PD-L1 and other biomarker expression in patients’ tumors. Methods: Forty patients ≥18 years of age with advanced STS will be enrolled. This is a phase 1/2 study using a defined dose of ipilimumab (1 mg/kg i.v. q 12 weeks), nivolumab (3 mg/kg i.v. q 2 weeks), and escalating doses of trabectedin (1.0, 1.3, 1.5 mg/m2 i.v. q 3 weeks). I. Dose Escalation Phase 1 (previously treated patients): The study will employ the standard “cohort of three” design. The maximum tolerated dose is defined as the highest safely tolerated dose, where not more than one patient experienced DLT, with the next higher dose level having at least two patients who experienced DLT. II. Expansion Phase 2 (previously untreated patients): An additional 22-28 patients will receive trabectedin at the MTD and defined doses of ipilimumab and nivolumab to assess overall safety and potential efficacy in a greater number of patients. Patients may continue treatment until significant disease progression or unacceptable toxicity occurs. Statistical Considerations: NIH CTCAE v4.03 and RECIST v1.1 will be used. Categorical variables will be summarized by the n and percent in each category. Point estimates for efficacy endpoint incidences will be accompanied by a 2-sided 95% exact binomial CI. Time to event endpoints will be summarized descriptively using the KM method. The analyses of all study objectives will be descriptive and hypothesis generating, for planning Phase 2/3 studies. Clinical trial information: NCT 03138161.

Administration of aldoxorubicin and 14 days continuous infusion of ifosfamide/mesna in metastatic or locally advanced sarcomas

11051

Background: Aldoxorubicin (A) has demonstrated superior anti-tumor efficacy and lack of cumulative cardiac toxicity in multiple studies. A is doxorubicin (D) with a linker which rapidly binds in vivo to albumin after iv. We studied the combination of A administered on Day 1 with continuous infusion (CI) of ifosfamide/Mesna (I-M) days 1-14, as first line therapy or second line therapy in patients with soft tissue sarcomas (STS) to evaluate efficacy and toxicity. Methods: 27 patients have entered the study at 250 mg/m2 ( 185 mg/m2 D equiv) administered on Day 1. I-M (1 g/m2 of each per day) was given up to 14 days as a CI via an out-patient portable pump. Chemotherapy cycles were repeated at 28 day interval. I-M was limited to a maximum of 6 cycles to avoid cumulative marrow toxicity, but A was continued per investigator decision in responding or SD patients for clinical benefit. Subjects were followed for tumor response (RECIST 1.1) by CT scans and echocardiogram/ECG for cardiac toxicity every 8 weeks along with standard labs. Enrollment continues up to 50 patients. Results: Demographics: Leiomyosarc. = 20%, liposarc. = 20%, synovial sarc. = 20%, rhabdosarc. = 8%, others = 32%. Caucasian, 11% Asian, 4% Black; 67% no prior tx, 26% 1 prior tx, 7% > 1 prior tx; Median cum. A = 1000 mg/m2 (740 mg/m2 D eq.; 185-4070 mg/m2 D eq.); I = 6.9 g/m2 (2.1-12.6 g/m2). Best response: 42% PR, 58% SD. Median PFS not reached. 10 subjects with either PR or SD had surgery to remove accesible tumors. Range of tumor necrosis = 70 to > 95%. Grade 3/4 AEs: neutropenia = 78%, febrile neutropenia = 9%, thrombocytopenia = 22%, anemia = 65%, nausea = 4%. Related SAEs = 4 (febrile neutropenia (2), pyrexia, stomatitis). No tx related deaths. No clinically significant cardiac AEs, no decrease in LVEF > 20% Conclusions: A can be administered for prolonged periods and safely with CI ifosfamide/mesna and achieves high ORR and SD with substantial tumor necrosis. Clinical trial information: NCT02235701.