Increasing targeted therapy options for patients with relapsed cancer with broader somatic gene panel analysis from the primary tumor: The Profiler02 randomized phase II trial

3130

Background: PROFILER-02 is a multicenter randomized prospective study comparing the proportion of metastatic cancer patients (pts) with Targeted Agent (TA) recommendation provided by large NGS panel (FOne panel, 324 genes) vs home 87-gene NGS panel (CTRL) (PMID 30865223). Methods: Adult pts with advanced/metastatic cancer during 1st or 2nd line of therapy without known targetable gene alteration were eligible and randomized (1:1) to FOne vs CTRL panel. Both panels were performed for each patient. The randomization arm defined the first panel reviewed by dedicated Molecular Tumor Board (MTB) at disease progression while the 2nd panel remained blinded. The primary objective was the pts rate with at least one TA recommendation by the MTB using either FOne or CTRL panel. The study was designed in order to detect difference in proportions of 10% between the two panels. A sample size of 289 pts with both panels were requested to show this difference with an expected proportion of discordant pairs of 20% using a McNemar's test with 98% power and 5% two-sided significance level. Secondary endpoints included number of pts receiving at least one TA, progression free survival (PFS) and overall survival (OS). Results: From June 2017 to June 2019, among the 339 included pts 171 and 168 pts were randomized in FOne or CTRL panels’ first use, respectively. Median age was 57 years [19.0 - 85.0]; 54.9% were female. The median time from randomization to first MTB was 7.62 months [range 0.80 - 48.1]. Among the 339 pts, 147 pts (43.4%) had no TA recommendation, 108 pts (31.9%) had at least one TA recommendation according to both panels, 67 pts (19.8%) had one or more TA recommendation according to FOne panel only and 17 pts (5%) according to CTRL panel only (McNemar p < 0.001). At the time of the analysis, 51/339 (15%) pts started recommended treatment: 27 pts (8%) with TA recommendation from both panels, 21 pts (6.2%) from FOne only and 3 pts (0.3%) from CTRL only. Main initiated TA were PARP inh. (FOne n = 12; CTRL n = 9), PI3K/AKT/mTOR inh. (FOne n = 10; CTRL n = 9) and immunotherapy (ICI) (FOne n = 7; CTRL n = 0). Median PFS following first MTB were 3.2 months (95% CI 2.5-3.8) and 2.6 months (95% CI 2.0-3.8), median OS were 8.7 months (95% CI 6.6-10.8) and 8.4 months (95% CI 6.4-9.7), in the FOne and CTRL arm, respectively. Conclusions: Larger NGS panel including Tumor Mutational Burden increased the number of recommended options (TA and ICI), as well as the number of treatment initiation. Clinical trial information: NCT03163732.

Interim safety and efficacy results from AURELIO-03: A phase 1 dose escalation study of the IL-2/IL-15 receptor βγ superagonist SOT101 as a single agent and in combination with pembrolizumab in patients with advanced solid tumors

2502

Background: SOT101 (previously SO-C101) is a fusion protein of IL-15 and the IL-15 receptor α sushi+ domain. Synergistic effects of SOT101 and an anti-programmed cell death protein 1 antibody have been validated in various tumor mouse models inducing a protective memory response. Methods: In this phase 1 study, safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of increasing doses of SOT101 administered subcutaneously were investigated in patients (pts) with advanced solid tumors as monotherapy (Part A) and in combination with pembrolizumab every 3-week cycle (Part B). Dose escalation followed a standard 3+3 design. Data cut-off was 26 January 2022. Results: Overall, 51 pts were treated: 30 in Part A monotherapy at 0.25 to 15 μg/kg SOT101 and 21 in Part B combination therapy (Tx) at 1.5 to 12 μg/kg SOT101. The median (range) number of previous lines of Tx was 3 (1-9) in Part A and 2 (1-6) in Part B. In Part A, 19 (63.3%) pts had previous check-point inhibitor (CPI) Tx, of whom 9 (30 %) were refractory, 5 (16.7%) relapsed. In Part B, 11 pts (52.4%) had previous CPI Tx, and the outcome was 9 (42.9%) pts relapsed, 1 (4.8%) refractory. The most common treatment-emergent adverse events (TEAEs) were transient, and included pyrexia, chills, lymphopenia, anemia, transaminase elevation and vomiting. Most TEAEs were ≤ Grade 2. No treatment-related death was reported. For both monotherapy and combination Tx, the recommended phase 2 dose of SOT101 was determined to be 12 μg/kg. In Part A, in 13 pts at 6 to 12 μg/kg SOT101, the observed clinical benefit rate was 38%. A partial response (PR) was confirmed in 1 pt with skin squamous cell carcinoma, CPI refractory, PR duration 46 days (d), on treatment 154 d. Four pts (all CPI pretreated) had stable disease (SD), range 33-183 d. Final median duration on treatment was 84 d, range 43-183 d. The median duration of clinical benefit was 190 d. In Part B, the observed clinical benefit rate across all SOT101 doses was 63%. A complete response (CR) was confirmed in 1 pt with mesothelioma, CPI naïve, starting at the first tumor assessment, and the pt is ongoing in cycle 5. Three pts, 2 CPI pretreated, had a PR, range 51-232 d, 2 ongoing with PR, and 1 Tx discontinuation while still on PR. Five pts, 3 CPI pretreated, had SD, range 92-340 d, 2 ongoing with SD. The 3 CPI pretreated pts had SD range 41-340 d, 1 pt ongoing. The preliminary median duration on combination Tx was 113 d, range 7-429 d. The preliminary median duration of clinical benefit was 131 d. Conclusions: SOT101 as monotherapy and in combination with pembrolizumab showed a favorable safety profile. Highly promising efficacy signals with one ongoing CR and several long-lasting PRs were reported in CPI-naïve and CPI pretreated pts, including CPI-resistant tumors. Clinical trial information: NCT04234113.

REGOMUNE: Phase II study of regorafenib plus avelumab in solid tumors—Results of the gastroenteropancreatic neuroendocrine carcinomas (GEP-NEC) cohort

4125

Background: There is no standard treatment for patients (pts) with advanced extra-pulmonary neuroendocrine tumors (NET) and carcinomas (NEC) after failure of chemotherapy in the metastatic setting. PD-1/PD-L1 expression is frequent in these tumors. Combining anti-PD1/PDL1 agents with anti-angiogenics has been shown to be synergistic in several tumor models. Methods: This is a single-arm open-label multicentric phase II trial assessing the efficacy and safety of regorafenib (R) (160 mg QD 3weeks/4) + Avelumab (A) (10 mg/kg every 2 weeks) combination in pts with advanced or metastatic grade 2 or 3 (G2/3) gastroenteropancreatic (GEP)-NET or GEP-NEC. The primary endpoint was the confirmed objective response rate, based on central review according to RECIST 1.1. Secondary endpoints included: 1-year progression free survival (PFS), 1-year overall survival (OS), and Safety using NCI-CTCAE v5.0. Correlative studies were planned from pts tumor samples obtained at baseline. Results: Between May 2019 and Apr. 2021, 46 pts were enrolled in 6 centers. Median age was 63 (range 31 – 80). 10 pts presented with a NEC and 36 pts with a G2/3 NET. Median follow-up was 6.5 months (95% CI: 5.3 - 9.6). Median number of previous treatment lines was: 2 (range 0 – 8). 39 (84.8%) pts experienced at least 1 dose modification or treatment interruption. The most common grade 3/4 adverse events were : Hypertension (13% of pts), fatigue (13%), and diarrhea (11%). One death was related to the treatment. Among the 42 assessable pts, 7 (16.7%) achieved a partial response: 6 pts with a G2/3 NET and 1 patient with a NEC. 22 (52.4%) pts demonstrated stable disease, 22 (52.4%) pts had tumor shrinkage and 10 (23.8%) pts had progressive disease. 3 (7.1%) pts were inevaluable as per RECIST. The median duration of response was 15.5 months (95%CI: 3.7 - not reached (NR)). The median PFS and OS were 5.5 months (95% CI: 3.6 – 9.2) and NR respectively. One year OS rate was 69.4 % (95% CI: 45.1 % – 84.5 %). Conclusions: REGOMUNE is the largest prospective study ever conducted in pts with grade 2/3 GEP-NET or GEP-NEC refractory to cytotoxic chemotherapy. The R+A combination has significant clinical activity in pts with refractory disease. Full Biomarkers analyses will be presented at the meeting. Clinical trial information: NCT03475953.

Identifying mechanisms of acquired immune escape from sequential, paired biopsies

2519

Background: Resistance to immune checkpoint blockade (ICB) can manifest as disease progression either at the initiation of treatment (primary resistance) or after some initial response (acquired resistance). To better understand the mechanisms underlying acquired resistance, the imCORE Network is conducting a study (NCT03333655) to examine changes in tumor biology from pre-treatment to disease progression across cancer types. Methods: Eligible patients included those experiencing clinical benefit on ICB (defined as objective response or stable disease longer than 6 months) and had evaluable tissue samples from both pre-treatment and within 30 days of progression. Samples were subjected to whole exome sequencing (WES), RNA sequencing (RNA-Seq), and immunohistochemistry (IHC). Whole blood samples or adjacent normal tissue were used as a reference for tumor variant calling. Results: As of December 3rd, 2021, 24 enrolled patients have complete sample pairs. Of those, melanoma, bladder, and lung were most common (n = 7, 6 and 5 pairs, respectively), but our cohort also included patients with breast cancer, squamous head & neck, and renal cell carcinoma. IHC data unexpectedly showed a modest, but consistent increase in tumor infiltrating CD8+ T cells at progression. In addition, IHC evidence of a decrease in MHC-I proteins (HLA-A and B2M) suggest that in 5 out of 24 cases, key proteins needed for antigen presentation are lost. Global differential gene expression analysis showed that immune gene expression was significantly increased at progression, including numerous chemokines and significant enrichment in gene sets responsible for antigen presentation machinery. Protein-altering mutations at progression appeared in B2M in one patient, and CXCL9 in another. However, in most cases it is unclear what genetic alterations are responsible. We do not observe evidence of consistent IFNγ and Jak/stat signaling loss or antigen presentation loss. Conclusions: While ICB resistance is thought to be associated with a lack of immune response within the TME, we found that acquired resistance is usually associated with either maintenance or an increase in immune infiltration. Multiple alterations that are unique to individual patients also continue to emerge. Our data shows ICB resistance is multifactorial and associated with dynamic changes to markers amid immune activation and inhibition. Clinical trial information: NCT03333655.

REGOMUNE: A phase II study of regorafenib plus avelumab in solid tumors—Results of the oesophageal or gastric carcinoma (OGC) cohort

4060

Background: Combination VEGF and PD-1/PD-L1 axis blockade has shown benefit in various tumors and is emerging as a promising combination strategy. Methods: This is a single-arm open-label multicentric phase II trial assessing the efficacy and safety of regorafenib (R) (160 mg QD 3weeks/4) + avelumab (A) (10 mg/kg every 2 weeks) combination in advanced or metastatic oesophageal or gastric carcinoma (OGC) patients (pts). The primary endpoint was the confirmed objective response rate, based on central review according to RECIST 1.1. Secondary endpoints included: 1-year progression free survival (PFS), 1-year overall survival (OS), and safety using NCI-CTCAE v5.0. Correlative studies were planned from pts tumor samples obtained at baseline. Results: Between Dec. 2018 and Mar. 2021, 49 pts were enrolled in 6 centers: 33 adenocarcinoma (ADK), 16 squamous cell carcinoma (SCC). Median age was 63.9 (range 33 – 80). Median follow-up was 14.5 months. Median number of previous treatment lines was: 2 (range 1 – 6). 29 (59.2%) pts experienced at least 1 dose modification or treatment interruption due to an adverse event related to treatment. The most common grade 3/4 adverse events were : Hypertension (12.2% of pts), palmar-plantar erythrodysesthesia syndrome (10.2%), and hypophosphatemia (8.2%). No death was related to the treatment. Among the 42 (29 ADK and 13 SCC) pts who had at least one imaging tumor assessment, 8 (19.1%) achieved a partial response, 5 (17.2%) and 3 (23.1%) in the ADK and SCC group respectively. 12 pts (28.6%) demonstrated stable disease and 22 pts (52.3%) had progressive disease. The median PFS and OS were 1.9 months (95%CI 1.8 – 3.5) and 7.5 months (95%CI 4.5 – 15.7) respectively. Conclusions: The R+A combination is associated with encouraging antitumor activity in patients with OGC. Full Biomarkers analyses will be presented at the meeting. Clinical trial information: NCT03475953.

LEAP-005: A phase 2 multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the gastric cancer cohort

4030

Background: Lenvatinib, an anti-angiogenic multiple receptor tyrosine kinase inhibitor, in combination with the anti‒PD-1 antibody pembrolizumab, has demonstrated promising antitumor activity with manageable safety in the first- or second-line in a phase 2 trial of patients with advanced gastric cancer. LEAP-005 (NCT03797326) is a phase 2, multicohort, nonrandomized, open-label study evaluating efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here, we present findings from the gastric cancer cohort of LEAP-005. Methods: Eligible patients were aged ≥18 years with histologically or cytologically confirmed metastatic and/or unresectable gastric cancer, received at least 2 prior lines of therapy, had measurable disease per RECIST v1.1, ECOG PS of 0‒1, and provided a tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles of pembrolizumab (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the gastric cancer cohort; 87% were male, 58% were aged < 65 years, and 71% had PD-L1 combined positive score (CPS) ≥1. Median time from first dose to data cutoff (April 10, 2020) was 7.0 months (range, 1.9‒11.9); 19 patients (61%) had discontinued treatment. ORR was 10% (95% CI, 2‒26); 1 patient had CR (3%), and 2 had a PR (6%). 12 patients (39%) had SD. Median DOR was not reached (range, 2.1+ to 2.3+ months). DCR was 48% (95% CI, 30‒67). Median PFS was 2.5 months (95% CI, 1.8‒4.2). Median OS was 5.9 months (95% CI, 2.6‒8.7). 28 patients (90%) had treatment-related AEs, including 13 patients (42%) with grade 3‒5 AEs. 1 patient had a treatment-related AE that led to death (hemorrhage). 8 patients (26%) had immune-mediated AEs: hypothyroidism (n = 5), hyperthyroidism (n = 2), and pneumonitis (n = 1). There were no infusion-related reactions. Conclusions: In patients with advanced gastric cancer who received 2 prior lines of therapy, lenvatinib plus pembrolizumab demonstrated promising antitumor activity and a manageable safety profile. Based on these data, enrollment in the gastric cancer cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

LEAP-005: A phase 2 multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the colorectal cancer cohort

3564

Background: Pembrolizumab (pembro), an anti-PD-1 antibody, is approved for the treatment of patients (pts) with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair (MMR) deficient colorectal cancer, both as first-line treatment and after progression following treatment with fluoropyrimidine, oxaliplatin, and irinotecan. The combination of lenvatinib, a multiple receptor tyrosine kinase inhibitor, and anti-PD-1 treatment showed synergistic antitumor activity in preclinical models. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembro in pts with previously treated advanced solid tumors. We present findings from the colorectal cancer cohort. Methods: In this nonrandomized, open-label, phase 2 study, adult pts (aged ≥18 y) with histologically/cytologically documented metastatic and/or unresectable colorectal cancer, non–MSI-H/pMMR tumor per local determination, previous treatment with oxaliplatin and irinotecan in separate lines of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and a tissue sample evaluable for PD-L1 expression were eligible. Pts received lenvatinib 20 mg QD plus pembro 200 mg Q3W for up to 35 cycles of pembro (̃2 y) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 y in pts with clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 wks, then Q12W to week 102, and Q24W thereafter. Results: 32 pts with colorectal cancer received treatment with lenvatinib plus pembro (median age, 56 y [range, 36-77]; male, 81%; 3L, 91%); median time from first dose to data cutoff (April 10, 2020) was 10.6 mo (range, 5.9-13.1). ORR was 22% (95% CI, 9–40; table). Grade 3–5 treatment-related AEs occurred in 16 (50%) pts. Treatment-related AEs led to treatment discontinuation in 3 pts (grade 2 ischemic stroke [n = 1], grade 3 increased liver transaminases [n = 1], grade 5 intestinal perforation [n = 1]). Conclusions: In pts with previously treated advanced non–MSI-H/pMMR colorectal cancer, lenvatinib plus pembro demonstrated promising antitumor activity and a manageable safety profile. Enrollment in the colorectal cohort was expanded to 100 pts. Clinical trial information: NCT03797326. [Table: see text]

Regomune: A phase II study of regorafenib + avelumab in solid tumors—Results of the biliary tract cancer (BTC) cohort

4096

Background: Regorafenib (R) has shown promising efficacy in patients (pts) with BTC refractory to standard chemotherapy. Anti-PD1/PD-L1 antibodies have only limited clinical activity. Synergy between R and anti–PD-1/PD-L1 antibodies has been shown in pre-clinical solid tumor models. Methods: This is a single-arm open-label multicentric phase II trial (Bayesian adaptive design) assessing the efficacy and safety of R (160 mg QD 3weeks/4) + avelumab (A) (10 mg/kg every 2 weeks) combination in BTC pts. The primary endpoint was the objective response rate under treatment, based on central review according to RECIST 1.1. Secondary endpoints included: 1-year progression free survival (PFS), 1-year overall survival (OS), and Safety using NCI-CTCAE v5.0. Correlative studies were planned from pts tumor samples obtained at baseline. Results: Between Nov. 2018 and Nov. 2019, 34 BTC pts were enrolled in 4 centers. Median age was 63 (range 36 – 80). Median follow-up was 9.8 months. Median number of previous treatment lines for metastatic or locally advanced disease was: 2 (range 1 – 4). Twenty-nine (85.3%) pts experienced at least 1 dose modification or treatment interruption of R or A due to an adverse event (AE) related to the treatment. The most common grade 3/4 AEs were : Hypertension (17.6%), Fatigue (14.7%), and maculo-papular rash (11.8%). No death was related to the treatment. Among the 29 pts with at least one imaging tumor assessment, 4 (13.8%) achieved a partial response, and 11 (37.9%) demonstrated stable disease including 10 (34.5%) pts with tumor shrinkage. Fourteen pts (48.3%) had progressive disease. The median PFS and OS were 2.5 months (95%CI 1.9 – 5.5) and 11.9 months (95%CI 6.2 – NA) respectively. Baseline tumor samples were available for 27 pts. High IDO and PD-L1 expression at baseline was associated with better outcome. Conclusions: The R+A combination is associated with significant anti-tumor activity with promising survival rates in this heavily pre-treated population. Full Biomarkers analyses will be presented at the meeting. Clinical trial information: NCT03475953.

Randomized phase Ib study to evaluate safety, pharmacokinetics and therapeutic activity of simlukafusp α in combination with atezolizumab ± bevacizumab in patients with unresectable advanced/ metastatic renal cell carcinoma (RCC) (NCT03063762)

4556

Background: Simlukafusp α ([SIM], FAP-IL2v) is a novel IL-2v immunocytokine engineered to preferentially activate effector CD8 T and NK cells, but not regulatory T cells (Tregs), due to abolished binding to Interleukin-2 receptor α (IL-2Rα) and retained affinity to IL-2Rβγ. High affinity binding of SIM to fibroblast activation protein (FAP), expressed on cancer-associated fibroblasts, mediates its accumulation in malignant lesions. Methods: The Dose-Escalation (DE) consisted of: Arm A: SIM 5-25 mg weekly for 4 weeks, and every 2 weeks (Q2W) thereafter in combination with atezolizumab [ATZ] 840mg Q2W; and Arm B: same as Arm A + bevacizumab [BEV] 10 mg/kg Q2W. Patients (pts) not previously treated were evaluated in the Extension Part: Arm C (n=3): SIM + ATZ every 3 weeks (Q3W); or Arm D (n=25): SIM + ATZ + BEV (“triplet”) Q3W. Primary objectives were: finding the recommended dose of SIM and assessment of objective response rate (ORR) by RECIST v1.1. Results: We enrolled 69 pts with unresectable advanced/ metastatic clear-cell and/or sarcomatoid RCC. Median age of patients was 57 years (range: 35-78). The recommended dose for extension of SIM was 10 mg. Median treatment duration in days in each arm were: A: 106 (range: 1-877); B: 324 (8-940); C: 659 (71-768); D: 437 (1-682). Twenty-five pts are evaluable for therapeutic activity in Arm A [ORR: 24% (6 PR; 90% CI 12.95, 40.12)]; 15 in Arm B [46.7% (1 CR, 6PR; 90% CI 27.67, 66.68)]; 3 in Arm C [33.3% (1PR; 90% CI 7.83, 74.65)]; and 23 in Arm D [47.8% (2 CR, 9 PR; 90% CI 35.74, 68.15)]. Twelve patients are ongoing on study treatment. Treatment related grade 3 and 4 adverse events (AE) occurred respectively in 69.7% and 9.1% patients. The most common serious AEs were pyrexia (10.6 %) and infusion-related reactions (9.1%). 65.2% Of the patients reported at least one AE of elevations in liver transaminases/GGT/ alkaline phosphatase/bilirubin. Drug-related AEs led to dose modification/interruption in 37.9 % of the pts, and treatment discontinuation in 3% of the patients. SIM led to preferential expansion and activation of NK and CD8 T cells (but not Tregs) in peripheral blood and augmented tumor infiltration and tumor inflammation. Intriguingly responses were observed not only in pts with PD-L1 positive or inflamed tumors, but also in pts with PD-L1 negative tumors (n=13) or poorly infiltrated tumors classified as immune deserts (n=2). Conclusions: The combination of SIM with ATZ ± BEV was feasible with an acceptable safety profile. Clinical activity was more favorable for the triplet among the study Arms, but comparable to the ATZ + BEV combination in the IMmotion151 (Rini B, et al 2019). Observed pharmacodynamic findings were consistent with the expected effects. Clinical trial information: NCT03063762.

Lenvatinib plus pembrolizumab for patients with previously treated biliary tract cancers in the multicohort phase 2 LEAP-005 study

4080

Background: Second-line treatment options for patients with biliary tract cancers (BTC) are limited. Lenvatinib, an anti-angiogenic multikinase inhibitor, in combination with the programmed death-1 immune checkpoint inhibitor pembrolizumab, has demonstrated promising antitumor activity with a manageable safety profile in patients with select advanced solid tumors. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here we present results from the BTC cohort of LEAP-005. Methods: In this nonrandomized, open-label, phase 2 study, eligible patients were aged ≥18 years with histologically or cytologically documented advanced (metastatic and/or unresectable) BTC with disease progression after 1 prior line of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints were the disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the BTC cohort (ECOG PS 1, 55%; 84% ex-US). As of April 10, 2020, median time from first dose to data cutoff (DCO) was 9.5 months (range, 3.1‒11.9), with 8 patients on treatment at DCO. There were 3 (10%) PRs and 18 (58%) SDs. ORR was 10% (95% CI, 2‒26), and DCR was 68% (95% CI, 49‒83). Median DOR was 5.3 months (range, 2.1+ to 6.2). Median PFS was 6.1 months (95% CI, 2.1‒6.4). Median OS was 8.6 months (95% CI, 5.6 to NR). Treatment-related AEs occurred in 30 patients (97%), including 15 (48%) who had grade 3 AEs; there were no grade 4 or 5 treatment-related AEs. 2 (6%) discontinued treatment due to treatment-related AEs (myocarditis, pyrexia; n = 1 each). The most frequent treatment-related AEs were hypertension (42%), dysphonia (39%), diarrhea (32%), fatigue (32%), and nausea (32%). 14 patients (45%) had immune-mediated AEs and 1 patient (3%) had an infusion-related reaction. Conclusions: Lenvatinib plus pembrolizumab demonstrated encouraging efficacy and manageable toxicity in patients with advanced BTC who had received 1 line of prior therapy. Based on these data, enrollment in the BTC cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

REGOMUNE: A phase II study of regorafenib plus avelumab in solid tumors—Results of the non-MSI-H metastatic colorectal cancer (mCRC) cohort

4019

Background: Regorafenib (R) has been shown to modulate anti-tumor immunity by different mechanisms including reduction of tumor-associated macrophages (TAMs). Synergy between R and anti–PD-1/PD-L1 antibodies has been shown in pre-clinical models. Methods: This is a single-arm open-label multicentric phase II trial assessing the efficacy and safety of R (160 mg QD 3weeks/4) + Avelumab (A) (10 mg/kg every 2 weeks) combination in non MSI-H mCRC patients (pts). The primary endpoint was the confirmed objective response rate, based on central review according to RECIST 1.1. Secondary endpoints included: 1-year progression free survival (PFS), 1-year overall survival (OS), and Safety using NCI-CTCAE v5.0. Correlative studies were planned from pts tumor samples obtained at baseline and C2D1. Results: Between Nov. 2018 and Oct. 2019, 48 pts were enrolled in 4 centers. Median age was 61.8 (range: 26.3-78.7). Median follow-up was: 7.2 months. Median number of previous treatment lines was: 3 (range: 1-7). 41 (87.2%) pts experienced at least 1 dose modification or treatment interruption. The most common grade 3/4 adverse events were palmar-plantar erythro-dysesthesia syndrome (29.8%), hypertension (23.4%) and diarrhea (12.8%). No death was related to the treatment. Among 40 pts who had at least one imaging tumor assessment, 12 (30%) had reduction in tumor burden. Best response was stable disease for 23 pts (57.5%) and progressive disease for 17 pts (42.5%). The median PFS and OS were 3.6 months (CI95%: [1.8 – 5.4]) and 10.8 months (CI95%: [5.9 – NA]) respectively. Baseline tumor samples and paired biopsies were available for 24 and 15 pts respectively. High infiltration by TAMs at baseline was significantly associated with adverse outcome (PFS: 1.9 vs 3.7 months, p=0.045; OS: 4.8 months vs NR, p=0.027). Increased tumor infiltration by CD8+ at C2D1 compared to baseline was significantly associated with better PFS (p=0.011). Combining low TAMs infiltration and low tumor cells to CD8+ T cells distance enabled the identification of a subgroup of pts (n= 6/24, 25%) more likely to benefit from R+A combination: median PFS: 5.3 vs 1.9 months (p=0.037); median OS: NR vs 5.3 months (p=0.02). Conclusions: The R+A combination achieved PFS and OS that compared favourably with historical data of R alone in this clinical setting. High-resolution analysis of tumor samples identified a composite score based on TAMs infiltration and tumor cell to CD8+ T cells distance which could be used as a biomarker in further studies investigating this approach in mCRC pts. Clinical trial information: NCT03475953 .

Phase I study of emactuzumab single agent or in combination with paclitaxel in patients with advanced/metastatic solid tumors reveals depletion of immunosuppressive M2-like macrophages

BACKGROUND

Emactuzumab is a monoclonal antibody against the colony-stimulating factor-1 receptor and targets tumor-associated macrophages (TAMs). This study assessed the safety, clinical activity, pharmacokinetics (PK) and pharmacodynamics (PD) of emactuzumab, as monotherapy and in combination with paclitaxel, in patients with advanced solid tumors.

PATIENTS AND METHODS

This open-label, phase Ia/b study comprised two parts (dose escalation and dose expansion), each containing two arms (emactuzumab, every 2 or 3 weeks, as monotherapy or in combination with paclitaxel 80 mg/m2 weekly). The dose-escalation part explored the maximum tolerated dose and optimal biological dose (OBD). The dose-expansion part extended the safety assessment and investigated the objective response rate. A PK/PD analysis of serial blood, skin and tumor biopsies was used to explore proof of mechanism and confirm the OBD.

RESULTS

No maximum tolerated dose was reached in either study arm, and the safety profile of emactuzumab alone and in combination does not appear to preclude its use. No patients receiving emactuzumab monotherapy showed an objective response; the objective response rate for emactuzumab in combination with paclitaxel was 7% across all doses. Skin macrophages rather than peripheral blood monocytes or circulating colony-stimulating factor-1 were identified as an optimal surrogate PD marker to select the OBD. Emactuzumab treatment alone and in combination with paclitaxel resulted in a plateau of immunosuppressive TAM reduction at the OBD of 1000 mg administered every 2 weeks.

CONCLUSIONS

Emactuzumab showed specific reduction of immunosuppressive TAMs at the OBD in both treatment arms but did not result in clinically relevant antitumor activity alone or in combination with paclitaxel. (ClinicalTrials.gov Identifier: NCT01494688).

BMS-986205, an indoleamine 2, 3-dioxygenase 1 inhibitor (IDO1i), in combination with nivolumab (nivo): Updated safety across all tumor cohorts and efficacy in advanced bladder cancer (advBC)

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Background: Nivo (anti–PD-1) has shown durable responses and manageable safety (ORR, 19.6%; grade 3‒4 treatment-related AEs [TRAEs], 18%) in advBC (Sharma et al. Lancet Oncol 2017), but prolonging survival in more pts requires additional approaches to overcome tumor evasion mechanisms. IDO1 allows tumor escape through kynurenine (KYN) production, which stimulates regulatory T cells and suppresses effector T-cell proliferation. Anti─PD-1 can upregulate IDO1, supporting the rationale for combining nivo with an IDO1i. BMS-986205 is a selective, potent, once-daily (QD) oral IDO1i that works early in the IDO1 pathway to reduce KYN production. BMS-986205 + nivo showed favorable safety and efficacy in heavily pretreated pts with select solid tumors (Luke et al. SITC 2017; NCT02658890). Updated safety across all tumor cohorts and efficacy in the immuno-oncology (I-O)–naive advBC cohort are reported. Methods: Dose-escalation methods in this phase 1/2a, open-label study were previously described; during expansion, pts received BMS-986205 100 or 200 mg QD + nivo 240 mg IV Q2W or 480 mg IV Q4W. Objectives included safety and ORR by RECIST v1.1 (includes unconfirmed responses). Results: As of Mar 2018, 516 pts received BMS-986205 + nivo; 45% had ≥2 prior regimens. TRAEs occurred in 57% of pts (grade 3‒4, 12%), the most common being fatigue (15%) and nausea (12%); 19 pts (4%) discontinued due to TRAEs, and 3 pts ( < 1%) died due to a TRAE (myocarditis, Stevens-Johnson syndrome, and hepatic failure). In all treated pts and within the advBC cohort (n = 30), the frequency and severity of TRAEs and rate of discontinuation due to TRAEs was lower with the 100- vs 200-mg BMS-986205 dose. Among the 27 pts with I-O–naive advBC, with a median duration of follow-up of 24 wk, ORR was 37% (3 CRs, 7 PRs), and the DCR was 56%; ORR in pts with tumor PD-L1 ≥1% (Dako PD-L1 IHC 28-8 pharmDx assay; n = 14) vs < 1% (n = 10) was 50% vs 30%. Conclusions: BMS-986205 + nivo was well tolerated in heavily pretreated pts, and tolerability was improved with the 100-mg BMS-986205 dose. Preliminary evidence of efficacy was observed in advBC, supporting further evaluation of BMS-986205 + nivo. Clinical trial information: NCT02658890.

Initial efficacy of anti-lymphocyte activation gene-3 (anti–LAG-3; BMS-986016) in combination with nivolumab (nivo) in pts with melanoma (MEL) previously treated with anti–PD-1/PD-L1 therapy

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Background: Signaling via LAG-3 and other T-cell inhibitory receptors (eg, PD-1) can lead to T-cell dysfunction and tumor immune escape. Simultaneous blockade of LAG-3 + PD-1 may synergistically restore T-cell activation and enhance antitumor immunity. In a phase 1/2a study, BMS-986016 (IgG4 mAb targeting LAG-3) ± nivo (IgG4 mAb targeting PD-1) demonstrated tolerability, peripheral T-cell activation, and preliminary clinical activity (NCT01968109; Lipson E, et al. J Immunother Cancer. 2016;4[s1]:173 [P232]). Here we describe preliminary efficacy of BMS-986016 + nivo in pts with MEL whose disease progressed on/after prior anti–PD-1/PD-L1 therapy, along with updated safety from all dose expansion pts. Methods: Pts with MEL must have had prior anti–PD-1/PD-L1 (± anti–CTLA-4 or BRAF/MEK inhibitors) and progressive disease (PD). Pts received BMS-986016 80 mg + nivo 240 mg IV Q2W. Primary objectives were safety and objective response rate (ORR; complete [CR] + partial [PR] response), disease control rate (DCR; CR + uCR + PR + uPR + stable disease [SD] > 12 wk), and duration of response (RECIST v1.1). Results: At data cutoff, 43 pts with MEL had been treated with BMS-986016 + nivo following PD on/after prior anti–PD-1/PD-L1 with known prior best responses of 1 CR, 9 PR, 12 SD, and 16 PD. Of the 43 pts, 30 (70%) also had prior anti–CTLA-4, 20 (47%) had ≥ 3 prior therapies, and 15 (35%) had BRAFmutations .In the 31 efficacy-evaluable pts to date, ORR was 16% (confirmed/unconfirmed) and DCR was 45% with benefit observed even in some pts refractory to prior anti–PD-1. Evaluations are ongoing for most pts, with median treatment duration of 10 wk for all 43 pts. Immunopathologic (eg, PD-1/PD-L1 and LAG-3 expression) and clinical characteristics of responders vs nonresponders will be presented. Any grade and grade 3/4 treatment-related AEs occurred in 46% and 9%, respectively, across all dose expansion pts (n = 129). Conclusion: Addition of BMS-986016 to nivolumab demonstrates encouraging initial efficacy in pts with MEL whose disease progressed on/after prior anti–PD-1/PD-L1 therapy, and a safety profile similar to nivolumab monotherapy. Clinical trial information: NCT01968109.

Abstract C2: Clinical safety, pharmacokinetics and early evidence of activity of the oral IAPs inhibitor Debio 1143 in combination with carboplatin and paclitaxel: a phase Ib study

Background: Resistance to apoptosis is a typical hallmark of cancer. Inhibitor of Apoptosis Proteins (IAPs) block caspase activation, modulate NF-kB signaling pathways, and are involved in resistance to standard chemo and radiation therapies. As such, IAPs antagonism represents an attractive target for therapeutic intervention. Debio 1143 is a potent orally-available monovalent SMAC mimetic antagonist of IAPs currently in clinical development. A previous phase I study showed Debio 1143 was well tolerated up to 900 mg QD as a single agent, with strong evidence of pharmacodynamic (PD) activity and appropriate pharmacokinetic (PK) disposition at doses ≥ 120 mg. [1] This Phase I study defined the dose limiting toxicities (DLTs), maximum tolerated dose (MTD), safety, PK, and PD of Debio 1143 in combination with carboplatin and paclitaxel.

Methods: Treatment-naïve and previously treated patients with squamous non-small cell lung cancer (NSCLC), and previously treated patients with triple negative breast cancer (TNBC) and platinum-resistant epithelial ovarian cancer (EOC) were treated with carboplatin (AUC 6) and paclitaxel 175 mg/m2 on day 1 of every 21-day-cycle up to a maximum of 6 cycles, combined with escalating doses of Debio 1143, administered once daily on days 1-5 of every 21-day cycle. The starting dose of Debio 1143 was 200 mg QD.

Results: Thirty-one patients were included in the study. Four patients are still on treatment. Hematological DLTs were observed in 2/4 patients in the first two dose levels despite the reduction of Debio 1143 dose to 100 mg. PK data suggested a PK interaction between Debio 1143 and paclitaxel. The study protocol was amended to reduce the doses of carboplatin to AUC 5 and paclitaxel to 135 mg/m2. Afterwards, patients received Debio 1143 doses of 100 mg (n = 2), 125 mg (n = 2), 175 mg (n = 2), 200 mg (n = 7), 225 mg (n = 5), 250 mg (n = 9). DLTs were febrile neutropenia (n = 2) and G3 ALT increase (n = 1). The MTD of Debio 1143 to be combined with carboplatin (AUC 5) and paclitaxel (135 mg/m2) is 250 mg QD. Most common treatment-related AEs reported in ≥ 15% of patients were asthenia (n = 13), decreased appetite (n = 11), diarrhea (n = 9), neutropenia (n = 9), thrombocytopenia (n = 8), anemia (n = 8), nausea (n = 7), fatigue (n = 7), vomiting (n = 4), AST increase (n = 4), hypomagnesaemia (n = 4), myalgia (n = 4),and epistaxis (n = 4). Paclitaxel exposure in patients dosed at 135 mg/m2 in combination with Debio 1143 was similar to historical control dosed at 175 mg/m2 due to a 25 to 40% reduction in clearance. Preliminary evaluation of PD endpoints confirmed Debio 1143-induced cIAP1 degradation in PBMCs at doses starting from 100mg. In line with the expected mechanism of action, modulation of serum PD markers of NF-kB signaling pathways and epithelial apoptosis was also observed during treatment. Twenty-three patients were evaluable for response. Partial responses by RECIST have been observed in 7 patients with EOC (6/17) and TNBC (1/5).

Conclusions: The combination of Debio 1143 with carboplatin and paclitaxel is well tolerated, with significant PD activity and hints of activity. The clinical PK interaction between Debio 1143 and paclitaxel is well-controlled and managed in the patients. These findings support a further Phase II program.

[1] HI Hurwitz et al., Cancer Chemother Pharmacol (2015) 75:851

Citation Format: Isabelle Ray-Coquard, Christophe Le Tourneau, Nicolas Isambert, Carlos A. Gomez-Roca, Philippe Cassier, Marie Paule Sablin, Bruno Gavillet, Daniela Purcea, Elisabeth Rouits, Claudia Schusterbauer, Claudio Zanna, Pierre Fumoleau, Jean-Pierre Delord. Clinical safety, pharmacokinetics and early evidence of activity of the oral IAPs inhibitor Debio 1143 in combination with carboplatin and paclitaxel: a phase Ib study. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C2.

CSF1R inhibition with emactuzumab in locally advanced diffuse-type tenosynovial giant cell tumours of the soft tissue: a dose-escalation and dose-expansion phase 1 study

BACKGROUND

Diffuse-type tenosynovial giant cell tumour (dt-GCT) of the soft tissue (alternatively known as pigmented villonodular synovitis), an orphan disease with unmet medical need, is characterised by an overexpression of colony-stimulating factor 1 (CSF1), and is usually caused by a chromosomal translocation involving CSF1. CSF1 receptor (CSF1R) activation leads to the recruitment of CSF1R-expressing cells of the mononuclear phagocyte lineage that constitute the tumor mass in dt-GCT. Emactuzumab (RG7155) is a novel monoclonal antibody that inhibits CSF1R activation. We have assessed the safety, tolerability and activity of emactuzumab in patients with Dt-GCT of the soft tissue.

METHODS

In this phase 1, first-in-human dose-escalation and dose-expansion study, eligible patients were aged 18 years or older with dt-GCT of the soft tissue with locally advanced disease or resectable tumours requiring extensive surgery, an Eastern Cooperative Oncology Group performance status of 1 or less, measurable disease according to Response Evaluation Criteria In Solid Tumors version 1.1, and adequate end-organ function. Patients with GCT of the bone were not eligible. Patients received intravenous emactuzumab at 900 mg, 1350 mg, or 2000 mg every 2 weeks in the dose-escalation phase and at the optimal biological dose in a dose-expansion phase. The primary objective was to evaluate the safety and tolerability of emactuzumab, and to determine the maximum tolerated dose or optimal biological dose. All treated patients were included in the analyses. Expansion cohorts are currently ongoing. This study is registered with ClinicalTrials.gov, number NCT01494688.

FINDINGS

Between July 26, 2012, and Oct 21, 2013, 12 patients were enrolled in the dose-escalation phase. No dose-limiting toxicities were noted in the dose-escalation cohort; on the basis of pharmacokinetic, pharmacodynamic, and safety information, we chose a dose of 1000 mg every 2 week for the dose-expansion cohort, into which 17 patients were enrolled. Owing to different cutoff dates for safety and efficacy readouts, the safety population comprised 25 patients. Common adverse events after emactuzumab treatment were facial oedema (16 [64%] of 25 patients), asthenia (14 [56%]), and pruritus (14 [56%]). Five serious adverse events (periorbital oedema, lupus erythematosus [occurring twice], erythema, and dermohypodermitis all experienced by one [4%] patient each) were reported in five patients. Three of the five serious adverse events-periorbital oedema (one [4%]), lupus erythematosus (one [4%]), and dermohypodermitis (one [4%])-were assessed as grade 3. Two other grade 3 events were reported: mucositis (one [4%]) and fatigue (one [4%]). 24 (86%) of 28 patients achieved an objective response; two (7%) patients achieved a complete response.

INTERPRETATION

Further study of dt-GCT is warranted and different possibilities, such as an international collaboration with cooperative groups to assure appropriate recruitment in this rare disease, are currently being assessed.

FUNDING

F Hoffmann-La Roche.

Sequential research-related biopsies in phase I trials: acceptance, feasibility and safety

BACKGROUND

Sequential tumour biopsies are of potential interest for the rational development of molecular targeted therapies.

PATIENTS AND METHODS

From June 2004 to July 2009, 186 patients participated in 14 phase I clinical trials in which sequential tumour biopsies (13 trials) and/or sequential normal skin biopsies (6 trials) were optional. All patients had to sign an independent informed consent for the biopsies.

RESULTS

Tumour biopsies were proposed to 155 patients and 130 (84%) signed the consent while normal skin biopsies were proposed to 70 patients and 57 (81%) signed the consent. Tumour biopsies could not be carried out in 41 (31%) of the 130 consenting patients. Tumour biopsies were collected at baseline in 33 patients, at baseline and under treatment in 56 patients. Tumour biopsies were obtained using an 18-gauge needle, under ultrasound or computed tomography guidance. Only nine minor complications were recorded. Most tumour biopsy samples collected were intended for ancillary molecular studies including protein or gene expression analysis, comparative genomic hybridization array or DNA sequencing. According to the results available, 70% of the biopsy samples met the quality criteria of each study and were suitable for ancillary studies.

CONCLUSIONS

In our experience, the majority of the patients accepted skin biopsies as well as tumour biopsies. Sequential tumour and skin biopsies are feasible and safe during early-phase clinical trials, even when patients are exposed to anti-angiogenic agents. The real scientific value of such biopsies for dose selection in phase I trials has yet to be established.