AB052. P-20. Phase 2, open-label study of second-line M7824 treatment in patients with locally advanced or metastatic biliary tract cancer

Background

Transforming growth factor β (TGF-β) signaling promotes tumor immunosuppression; its inhibition in the tumor microenvironment may enhance the response to anti-PD-L1 treatment. M7824 is an innovative first-in-class bifunctional fusion protein composed of 2 extracellular domains of TGF-βRII (a TGF-β “trap”) fused to a human IgG1 mAb against PD-L1. Building upon encouraging efficacy observed in a phase 1 study, the present study will evaluate M7824 clinical benefit in patients with pretreated biliary tract cancer (BTC).

Methods

This multicenter, international trial is evaluating M7824 monotherapy in patients with locally advanced or metastatic (LA/M) BTC unselected for tumor PD-L1 expression who had disease progression after or were intolerant to first-line platinum-based therapy. Eligible patients must have histologically or cytologically confirmed LA/M intrahepatic cholangiocarcinoma (CCA), extrahepatic CCA, or gallbladder cancer. Patients must not have received prior immunotherapy, therapy with checkpoint inhibitors, or anti-TGF-β therapy. Patients will receive M7824 1,200 mg every 2 weeks intravenously up to 24 months or until confirmed disease progression, unacceptable toxicity, or trial withdrawal. The primary endpoint is confirmed objective response; key secondary endpoints include duration of response, progression-free survival, overall survival, and safety.

Results

This is a trial in progress; results are pending.

Conclusions

BTCs are a group of cancers with poor prognosis and few treatment options. For second-line therapy, no standard of care exists, and overall response rates (ORRs) with chemotherapy are <10%. M7824 has demonstrated promising preclinical activity as well as antitumor activity and a manageable safety profile in two phase 1 studies. In an expansion cohort of study NCT02699515 of 30 patients with pretreated advanced BTC, M7824 monotherapy demonstrated a 23.3% confirmed ORR by investigator assessment, with durable responses. The present study is, therefore, supported by preclinical and clinical evidence and will provide further insight of M7824 in BTC. Previously presented at the 2019 Cholangiocarcinoma Foundation Conference, Borad et al . Reused with permission.

Phase I Trial of M7824 (MSB0011359C), a Bifunctional Fusion Protein Targeting PD-L1 and TGFβ, in Advanced Solid Tumors

Purpose: M7824 (MSB0011359C) is an innovative first-in-class bifunctional fusion protein composed of a mAb against programmed death ligand 1 (PD-L1) fused to a TGFβ "trap."Experimental Design: In the 3+3 dose-escalation component of this phase I study (NCT02517398), eligible patients with advanced solid tumors received M7824 at 1, 3, 10, or 20 mg/kg once every 2 weeks until confirmed progression, unacceptable toxicity, or trial withdrawal; in addition, a cohort received an initial 0.3 mg/kg dose to evaluate pharmacokinetics/pharmacodynamics, followed by 10 mg/kg dosing. The primary objective is to determine the safety and maximum tolerated dose (MTD); secondary objectives include pharmacokinetics, immunogenicity, and best overall response.Results: Nineteen heavily pretreated patients with ECOG 0-1 have received M7824. Grade ≥3 treatment-related adverse events occurred in four patients (skin infection secondary to localized bullous pemphigoid, asymptomatic lipase increase, colitis with associated anemia, and gastroparesis with hypokalemia). The MTD was not reached. M7824 saturated peripheral PD-L1 and sequestered any released plasma TGFβ1, -β2, and -β3 throughout the dosing period at >1 mg/kg. There were signs of efficacy across all dose levels, including one ongoing confirmed complete response (cervical cancer), two durable confirmed partial responses (PR; pancreatic cancer; anal cancer), one near-PR (cervical cancer), and two cases of prolonged stable disease in patients with growing disease at study entry (pancreatic cancer; carcinoid).Conclusions: M7824 has a manageable safety profile in patients with heavily pretreated advanced solid tumors. Early signs of efficacy are encouraging, and multiple expansion cohorts are ongoing in a range of tumors. Clin Cancer Res; 24(6); 1287-95. ©2018 AACR.

M7824 (MSB0011359C), a bifunctional fusion protein targeting PD-L1 and TGF-β, in patients with heavily pretreated CRC: Preliminary results from a phase I trial

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Background: Inhibiting the transforming growth factor β (TGF-β) pathway, which plays a key role in tumor immunosuppression, may enhance the response to programmed death 1/programmed death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs). M7824 (MSB0011359C) is an innovative first-in-class bifunctional fusion protein composed of a mAb against PD-L1 fused with the extracellular domain of TGF-β receptor II, which serves as a TGF-β “trap.” We report results in patients (pts) with heavily pretreated colorectal cancer (CRC), an area of high unmet need since these pts no longer respond to standard therapies. Methods: In this expansion cohort of the ongoing, phase 1, open-label trial NCT02517398, pts with heavily pretreated (≥3rd line) advanced CRC receive M7824 1200 mg q2w until confirmed progressive disease (PD), unacceptable toxicity or trial withdrawal. The primary objective is best overall response (BOR) per RECIST v1.1; secondary objectives include safety/tolerability. Results: As of 28 June 2017, 32 heavily pretreated pts with advanced CRC (87.5% had ≥3 prior therapies) received M7824 for a median duration of 7.1 (range: 2-38) weeks; 2 pts remained on treatment. Among the 29 evaluable pts, 1 had a confirmed partial response (PR; ongoing at 8 months), 1 had stable disease (SD) and 27 had PD as BOR per independent read. The pt with a PR had CRC that was microsatellite stable (MSS), consensus molecular subtype (CMS) 4, KRAS mutant (mt) and PD-L1+; this pt had the highest tumor cell PD-L1 expression in our cohort (20%; PD-L1 expression was generally low among the other 24 pts with available results). 4 pts (12.5%) experienced 5 different grade 3 treatment-related adverse events (AEs; adrenal insufficiency, anemia, blood bilirubin increased, enteritis [leading to discontinuation] and fatigue); there were no grade ≥4 treatment-related AEs or treatment-related deaths. Conclusions: In heavily pretreated pts with advanced CRC, 1 pt (MSS, CMS 4, KRAS mt and PD-L1+) had a durable PR, 1 had SD and 27 had PD as BOR. M7824 showed a manageable safety profile. Updated data – including PD-L1, TGF-β and CMS results – will be presented. A study in pts with CMS 4 is in preparation. Clinical trial information: NCT02517398.

M7824 (MSB0011359C), a bifunctional fusion protein targeting PD-L1 and TGF-β, in Asian patients with advanced solid tumors

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Background: Inhibiting the transforming growth factor β (TGF-β) pathway, which plays a key role in tumor immunosuppression, may enhance the response to programmed death 1/programmed death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs). M7824 (MSB0011359C) is an innovative first-in-class bifunctional fusion protein composed of a mAb against PD-L1 fused with the extracellular domain of TGF-β receptor II, which serves as a TGF-β “trap.” We report results in Asian patients (pts) with advanced solid tumors. Methods: NCT02699515 is a phase 1, open-label, 3 + 3 dose-escalation study. Pts receive M7824 at 3, 10 or 20 mg/kg q2w until confirmed progressive disease, unacceptable toxicity or trial withdrawal. The primary objective is to determine the safety and maximum tolerated dose (MTD); secondary objectives include pharmacokinetics (PK), immunogenicity and best overall response per RECIST v1.1. Results: As of 28 February 2017, 14 heavily pretreated pts (85.7% received ≥3 prior therapies) received M7824 for a median duration of 5.9 weeks (range: 2-40 weeks). Grade (gr) ≥3 treatment-related adverse events occurred in 3 pts (21.4%): 1 pt (3 mg/kg) had gr 4 hyponatremia and gr 3 hypopituitarism; 1 pt (20 mg/kg) had gr 3 intracranial tumor hemorrhage (dose-limiting toxicity; treatment discontinued [TD]); 1 pt (20 mg/kg) had gr 3 increased blood creatine phosphokinase, hyponatremia and hypoacusis (TD). PK data showed a dose-linear increase in exposure. Signs of efficacy were seen across all dose levels: 2 pts (colorectal cancer [CRC] associated with Lynch syndrome [3 mg/kg] and ovarian cancer [20 mg/kg]) achieved a confirmed partial response (PR) and 3 pts (gastric/gastroesophageal junction cancer [3 mg/kg], gastric cancer [3 mg/kg] and adenoid cystic carcinoma of the tongue [10 mg/kg]) achieved stable disease. Durations of response were 1.1+ months (ovarian; PR occurred after TD, with no further anticancer therapy) and 7.0+ months (CRC; treatment ongoing); both PRs were ongoing beyond the data cutoff. Conclusions: M7824 had a manageable safety profile in Asian pts with heavily pretreated advanced solid tumors; the MTD was not reached. Early signs of clinical efficacy are encouraging. Clinical trial information: NCT02699515.

M7824 (MSB0011359C), a bifunctional fusion protein targeting PD-L1 and TGF-β, in Asian patients with pretreated recurrent or refractory gastric cancer: Preliminary results from a phase I trial

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Background: Inhibiting the transforming growth factor β (TGF-β) pathway, which plays a key role in tumor immunosuppression, may enhance the response to programmed death 1/programmed death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs). M7824 (MSB0011359C) is an innovative first-in-class bifunctional fusion protein composed of a mAb against PD-L1 fused with the extracellular domain of TGF-β receptor II, which serves as a TGF-β “trap.” We report preliminary results in Asian patients with heavily pretreated gastric cancer. Methods: In this expansion cohort of the ongoing, phase 1, open-label trial NCT02699515, patients with recurrent or refractory unresectable stage IV gastric or gastroesophageal junction adenocarcinoma for which no standard therapy exists or standard therapy has failed receive M7824 1200 mg q2w until confirmed progressive disease, unacceptable toxicity or trial withdrawal. The primary objective is safety; secondary objectives include best overall response (BOR) per RECIST v1.1. Results: As of 6 September 2017, 31 heavily pretreated patients with advanced gastric cancer (67.7% received ≥3 prior anticancer therapies) received M7824 for a median duration of 6.1 (range: 2-30) weeks (median number of M7824 infusions: 3 [range: 1-13]); 8 patients remained on treatment. Four patients (12.9%) experienced grade 3 treatment-related adverse events (anemia and diarrhea 1 each and 2 rash). No treatment-related grade 4 AEs occurred. One grade 5 event (total 5 doses received) was considered possibly treatment related, but suspected rupture of preexisting thoracic aortic aneurysm was cited as other probable cause by the investigator. There were 5 confirmed partial responses (4 ongoing after 4-6 months of follow-up) based on investigator assessment of BOR (overall response rate: 16.1%). This is an ongoing study; updated data will be presented. Conclusions: These preliminary data show that M7824 resulted in a manageable safety profile in heavily pretreated Asian patients with gastric cancer. Early signs of clinical efficacy are encouraging. Clinical trial information: NCT02699515.

Evaluation of real-world treatment outcomes in patients with distant metastatic Merkel cell carcinoma following second-line chemotherapy in Europe

Background and aims

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer; few treatments exist for patients with advanced disease. Once tumors metastasize to distant sites, patients generally receive chemotherapy, but response duration and progression-free survival (PFS) are typically short. Few studies have assessed the efficacy of second-line chemotherapy for metastatic MCC. Here, we studied outcomes in patients who received ≥ 2 lines of chemotherapy for metastatic MCC.

Materials and methods

Patients in an MCC-specific registry diagnosed with stage IV MCC between November 1, 2004, and September 15, 2015, and treated with second-line or later chemotherapy were analyzed retrospectively. Patient records, including baseline characteristics, immunocompetent status, and responses to prior chemotherapy, were evaluated. Patients meeting eligibility criteria were followed through December 31, 2015.

Results

Of 29 patients with metastatic MCC and immunocompetent status who had received ≥ 2 lines of chemotherapy, 3 achieved a partial response, for an objective response rate (ORR) of 10.3% (95% CI, 2.2–27.4). In the overall population including patients with immunocompetent and immunocompromised status (n = 34), the ORR was 8.8% (95% CI, 1.9–23.7). The median duration of response was 1.9 months (range, 1.3–2.1 months; 95% CI, 1.3–2.1). In the immunocompetent population, median PFS and overall survival were 3.0 months (95% CI, 2.5–6.0) and 5.3 months (95% CI, 4.3–6.0), respectively.

Conclusions

The low response rates and limited durability confirm previous reports of the ineffectiveness of second-line or later chemotherapy in patients with metastatic MCC and provide a benchmark for assessing clinical benefit of new treatments.

Preliminary results from a phase 1 trial of M7824 (MSB0011359C), a bifunctional fusion protein targeting PD-L1 and TGF-β, in advanced solid tumors

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Background: M7824 (MSB0011359C) is a novel bifunctional fusion protein comprised of a fully human IgG1 monoclonal antibody against programmed death ligand 1 (PD-L1) fused to the soluble extracellular domain of transforming growth factor-β (TGF-β) receptor II, which acts as a TGF-β trap. We report preliminary data from a phase 1 trial of M7824 in patients (pts) with advanced solid tumors. Methods: NCT02517398 is a phase 1, open-label, 3+3 dose-escalation study. Eligible pts receive M7824 at 1, 3, 10, or 20 mg/kg Q2W until confirmed progressive disease, unacceptable toxicity, or trial withdrawal; treatment beyond progression is generally allowable. The primary objective is to determine the safety and maximum tolerated dose of M7824; secondary objectives include pharmacokinetics (PK), immunogenicity, and best overall response per RECIST v1.1. Results: 16 heavily pretreated pts with ECOG performance status 0-1 have received M7824. Our PK data show a dose-linear increase in exposure starting at a dose of 3 mg/kg; furthermore, M7824 saturates peripheral PD-L1 and sequesters any released plasma TGF-β1, -β2, and -β3 throughout the dosing period in a dose-dependent manner. Grade 3 drug-related treatment-emergent adverse events (TEAEs) occurred in 3 pts (skin infection secondary to grade 2 bullous pemphigoid [BP], lipase increased, and colitis with associated anemia); there were no grade 4-5 drug-related TEAEs. BP and colitis responded well to steroids. Colitis and its secondary events of anemia and rectal hemorrhage (in a previously radiated area) were considered dose limiting in 1 pt. There was preliminary evidence of efficacy across all dose levels, including 1 ongoing confirmed complete response (cervical), 1 durable partial response (pancreatic), a 25% reduction in the sum of diameters of target lesions after 2 doses of M7824 (cervical), and 2 cases of prolonged stable disease (pancreatic; carcinoid). Conclusions: Preliminary data from this phase 1 dose-escalation study suggest that M7824 has a manageable safety profile in pts with heavily pretreated advanced solid tumors. Early signs of clinical efficacy warrant further study. Clinical trial information: NCT02517398.

Comparative study of two PD-L1 expression assays in patients with non-small cell lung cancer (NSCLC)

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Background: Response to anti–PD-L1/PD-1 therapy in patients with NSCLC has been associated with tumor PD-L1 expression. Avelumab is a fully human anti‒PD-L1 IgG1 antibody that has shown antitumor activity in advanced NSCLC, with a trend for greater efficacy in patients with PD-L1+ vs PD-L1– NSCLC tumors, as assessed using a proprietary PD-L1 assay in development (Dako, Carpinteria, CA; based on antibody clone 73-10, Merck KGaA, Darmstadt, Germany). This study compares the analytical performance of the 73-10 assay with the FDA-approved PD-L1 IHC 22C3 pharmDx diagnostic assay (Dako) in NSCLC tumors. Methods: Formalin-fixed paraffin-embedded NSCLC tumor samples were obtained from a commercial source and from a study of first-line (1L) avelumab in patients with advanced NSCLC (NCT01772004). Tumor membrane PD-L1 expression was assessed with the 73-10 and 22C3 assays by immunohistochemistry. Correlation between assays was determined at different PD-L1 cut-off levels. Results: In initial staining of commercial NSCLC samples, the 73-10 assay showed a broad dynamic range. Of 148 commercial samples, the 73-10 assay with ≥1%, ≥50% and ≥80% cut-offs classified 64.2%, 36.5% and 23.6% of samples as PD-L1+, respectively, whereas 20.3% were PD-L1+ with the 22C3 assay at a pre-specified ≥50% cut-off. The overall percentage agreement between assays was 83.8% using the ≥50% cut-off for both assays, and 93.9% using the ≥80% cut-off for 73-10 and ≥50% for 22C3. In follow-up studies, 83 study samples from the 1L NSCLC cohort were evaluable with both assays. With the 73-10 assay at ≥1%, ≥50%, and ≥80% cut-offs, 79.5%, 45.8%, and 31.3% of study tumors, respectively, were PD-L1+; with the 22C3 assay at ≥1% and ≥50% cut-offs, 59.0% and 21.7% were PD-L1+. Conclusions: Using a high tumor cell PD-L1 staining cut-off, the 73-10 and 22C3 assays showed highly concordant staining of NSCLC samples, with similar sensitivity observed with an ≥80% cut-off for 73-10 and ≥50% for 22C3. Using a low frequency of tumor PD-L1 expression, data suggested that the 73-10 assay had greater sensitivity than the 22C3 assay. These results provide a rationale for additional studies using the 73-10 assay at various cut-offs within the avelumab trial program. Clinical trial information: NCT01772004.