Background: Prolgolimab is an IgG1 anti-PD-1 monoclonal antibody with the Fc-silencing 'LALA' mutation. The phase III DOMAJOR study assessed efficacy and safety of prolgolimab in combination with pemetrexed and platinum-based chemotherapy vs placebo in combination with pemetrexed and platinum-based chemotherapy as first-line treatment for advanced non-small cell lung cancer (NSCLC). Methods: 292 patients with advanced non-squamous NSCLC were randomized 1:1 to receive 4 cycles of pemetrexed, platinum-based drug and either prolgolimab (3 mg/kg Q3W) or placebo followed by prolgolimab/placebo with pemetrexed until disease progression or toxicity (<= 36 months). The primary endpoint was overall survival (OS). Results: After a median follow-up of 18 months, the median OS was not reached (95 % CI, 22.28 - NA) in the prolgolimab-combination group vs 14.6 months (95 % CI, 11.73 - 19.15) in the placebo-combination group (HR, 0.51; 95 % CI, 0.35 - 0.73, p = 0.0001). The OS improvement was independent of PD-L1 status. Median progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) was 7.7 months in the prolgolimab-combination group and 5.5 months in the placebo-combination group (HR, 0.65; 95 % CI, 0.49 - 0.85, p = 0.0004). The only adverse events that were reported in at least 10 % of the patients that were significantly more frequent in the prolgolimab-combination group were blood creatinine increased and dyspnoea. Conclusion: Among patients with advanced NSCLC the addition of prolgolimab to pemetrexed and a platinum- based drug increased OS and PFS, with no new safety concerns. This benefit was retained in patients with PD- L1 negative tumors. (ClinicalTrials.gov, NCT03912389)

9526 Background: BCD-145 (nurulimab) is a fully human IgG1 mAb with modified Fc-fragment (the 1st Gln is replaced by Glu in the heavy chain sequence, and there is no terminal dipeptide composed by Gly and Lys residues) that binds to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and blocks the interaction between CTLA-4 and its ligands. This allows to stimulate T-cell proliferation, cytokine production and induces antitumor immune response. Here we present the results of multicenter open-label single-arm multi-cohort phase I trial of pharmacokinetics (PK), pharmacodynamics (PD), safety, and immunogenicity of BCD-145 in pts with unresectable/metastatic melanoma (unr/mM). Methods: BCD-145 monotherapy in 3+3 dose escalation [0.1, 0.3, 1, 3, 10 mg/kg intravenously Q3W] was given to 15 pts with unr/mM with measurable disease, who had failed prior therapy, ECOG 0-2. Pts with brain mts, previous therapy with aCTLA-4 and/or aPD-1/PD-L1 drugs were not allowed. The main objective of the study was to evaluate PK, PD, tolerability, immunogenicity, safety, dose-limiting toxicity (DLT), maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) identification. Secondary objectives included tumor response rate (irRECIST). Results: BCD-145 proved safety and overall was well tolerated. DLT and MTD were not reached. Any grade (Gr) adverse events (AEs) occurred in 100% (15/15) of pts. 33.3% (5/15) of pts had AE/SAE of Gr 3-4, including hypertension Gr 3 (1 at 1 mg/kg), hypercalcemia Gr 4 (2 at 1 mg/kg), hypokalemia Gr 3 (2 at 1 mg/kg), neutropenia Gr 3 (1 at 0.3 mg/kg), anemia Gr 3 (1 at 1 mg/kg), lung infection Gr 3 with hospitalization (1 at 1 mg/kg). Only 2 pts had a treatment-related AE Gr 3-4. Immuno-related AE were identified in 46.7% (7/15), manifested by symptoms of thyroiditis (mainly Gr 1) and diarrhea Gr 2 (1 at 10 mg/kg). There was 1 death (at 1 mg/kg) due to progression. There is dose-dependent peak study drug serum concentrations and systemic exposure. Two dosage regimens (1 mg/kg, 3 mg/kg Q3W) allowed to achieve the optimal concentration. BCD-145 increased subpopulations of activated HLA-DR+ CD4+ and CD8+ T lymphocytes, CD4+ICOS+ T-lymphocytes, absolute lymphocyte counts in all cohorts without significant differences. Binding and neutralizing Abs against BCD-145 were detected in 2 pts from different dose cohorts (0.3 mg/kg, 1 mg/kg). PR and SD were registered in 2 pts of each response group. 30.8% of pts achieved disease control, which is consistent with published data on other CTLA-4 inhibitors. A dose of 1 mg/kg is determined as recommended phase 2 dose (RP2D). Conclusions: BCD-145 demonstrated a tolerable safety profile and preliminary anti-tumor activity in pts with unr/mM. Anti-tumor effects of BCD-145 were observed in pts who had progressed on prior treatment. Further co-targeting PD-1 and CTLA-4 simultaneously will achieve a better anti-tumor activity due to cooperative binding to exhausted T-cell subsets. Clinical trial information: NCT03472027 .

Background Prolgolimab is the first Russian PD-1 inhibitor approved for the first-line treatment of unresectable or metastatic melanoma and advanced non-small cell lung cancer. It was approved in two weight-based regimens of 1 mg/kg Q2W and 3 mg/kg Q3W, but because of re-evaluation of weight-based dosing paradigm, studying of a fixed-dose regimen was considered perspective.Methods We conducted a multicenter, single-arm, open-label efficacy, pharmacokinetics, and safety study to obtain data that would allow the approval of the new flat dosing regimen of prolgolimab in patients with previously untreated unresectable or metastatic melanoma (BCD-100-8/FLAT, NCT05783882). The primary objective was to prove the non-inferiority of prolgolimab 250 mg Q3W versus prolgolimab 1 mg/kg Q2W for the treatment of patients with unresectable or metastatic melanoma in terms of ORR according to RECIST 1.1. Patients from the MIRACULUM study (BCD-100-2/MIRACULUM, NCT03269565) comprised a historical control group.Results One hundred fourteen patients received prolgolimab 250 mg Q3W, and 61 patients received prolgolimab (Prolgo) 1 mg/kg Q2W (historical control). Objective response was achieved by 33.3% [95% confidence interval (CI): 24.8, 42.8] of patients in the Prolgo 250 mg group compared with 32.8% (95% CI: 21.3, 46.0) of patients in the Prolgo 1 mg/kg group. Risk difference was 0.00, 95% CI (-0.12; NA), p = 0.0082. Both regimens were well tolerated, and safety profiles were comparable. The pharmacokinetic analysis (PK) showed that the regimen with the fixed dose of 250 mg Q3W was characterized by higher PK parameters. The immunogenicity study did not detect binding antibodies to prolgolimab in any of the subjects.Conclusion The obtained results showed that the selected fixed dosing regimen of prolgolimab 250 mg Q3W is characterized by efficacy and safety parameters comparable to that observed for the 1 mg/kg Q2W regimen.

5536 Background: Here we present the final results of single-arm phase II CAESURA (NCT03912402) study of prolgolimab (anti-PD-1 antibody) with platinum doublet and bevacizumab in subjects with advanced cervical cancer (CC). Methods: 58 patients (pts) with metastatic or recurrent/persistent CC with measurable disease received prolgolimab (3 mg/kg) Q3W together with paclitaxel, platinum drug (cis- or carboplatin) and bevacizumab for 6 cycles and then therapy with prolgolimab and bevacizumab until disease progression or toxicity. Objective response rate (ORR) was assessed by central radiology review per RECIST 1.1 (primary endpoint) and iRECIST criteria. CT scans were performed after 9 and 18 weeks of treatment and in case of suspicion on disease progression. Results: Distant metastases at screening had 42 pts, 16 had recurrent or persistent CC. The median age of pts was 48 [38; 58] years old. Squamous cell carcinoma was diagnosed in 50 of 58 subjects. PD-L1 CPS ≥ 1 (22C3) was found in 45 pts, CPS < 1 in 6 cases. ORR per RECIST 1.1 was 63.8% (37 of 58 pts) and included 2 complete, 35 partial responses. ORR per iRECIST was 70.7% (41 of 58 pts) with 2 complete and 39 partial responses. At the cut-off date (12 months) PFS (secondary endpoint) per RECIST 1.1 criteria counted 8.5 (95% CI 5.7; 10.9) months, per iRECIST criteria it reached 13.1 (95% CI 8.1; 13.6) months. Median overall survival was not reached. Any grade adverse events (AEs) occurred in 98% (57/58) of pts, of them in 69% (40/58) they were related to study treatment, including 12 cases of severe events (gr. 3 or higher). Immune-related AEs (irAEs) occurred in 38% (22/58) of pts. The most common irAEs were gr. 1–2 endocrine disorders (26%), including thyroid disorders and one case of gr. 2 adrenal insufficiency. Other important irAEs included 2 cases of enterocolitis (gr. 3 and 4), 1 case of dermatitis (gr. 3), several cases of gr. 2–3 transaminase elevation (9%). In 15 pts at least one component of study treatment was discontinued due to AE, of them 4 events were related to study treatment (including immune-related enterocolitis and adrenal insufficiency). Conclusions: Prolgolimab in combination with chemotherapy and bevacizumab demonstrated promising efficacy, known and acceptable safety profile in pts with advanced CC. Phase III placebo-controlled trial evaluating prolgolimab with chemotherapy and bevacizumab (NCT03912415) as first-line therapy option in subjects with CC is ongoing. Clinical trial information: NCT03912402 .

5510 Background: Simlukafusp alfa (SIM; FAP-IL2v) comprises an interleukin-2 variant (IL-2v) moiety and an antibody against fibroblast activation protein-α (FAP). The binding of SIM to FAP, expressed on cancer-associated fibroblasts, accounts for retention and accumulation in malignant lesions. The engineered IL-2v moiety has an abolished binding to IL-2Rα while the affinity to IL-2Rβγ is retained, resulting in activation of immune effector CD8 T and NK cells, but not of regulatory T cells, and therefore may augment activity of PD-(L)1 inhibitors. Methods: The clinical activity and safety of the SIM and atezolizumab (ATZ) combination in patients with recurrent or metastatic (R/M) cervical squamous cell carcinoma (SCC) were evaluated in a phase 2 basket study (NCT03386721). Patients (pts) were treated with SIM 10 mg IV and ATZ 1200 mg IV once every 3 weeks. The primary endpoint was objective response rate (ORR) by RECIST v1.1 assessed by investigators. Secondary endpoints were: disease control rate (DCR), duration of response (DoR), progression free survival (PFS). Results: 47 Pts with ECOG ≥1 and median age of 53 years (range: 25-69) were enrolled. All pts were checkpoint inhibitor naïve and 40 (85%) had ≥ 1 previous lines of therapy in the metastatic setting. The median number of cycles was 6 (range: 1-29). The ORR was 27% (90% CI: 18, 39) and DCR was 71% (90% CI: 58, 80) in 44 response-evaluable patients: 2 (5%) had complete response, 10 (23%) partial response, and 19 (43%) stable disease. Responses were observed across PD-L1 subgroups (SP142 assay, IC/TC cut-off ≥ 1%) with 8/22 and 4/18 responders in PD-L1+ and PD-L1- patients, respectively. Responses were durable, the median DoR was 13.3 months (95% CI: 7.6, 14.7). PFS probability at 6 months was 0.4 (95% CI: 0.27, 0.59). The most common adverse events (AE) (reported in > 30% patients), irrespective of relatedness to treatment and severity, were pyrexia (74.5%), anemia (48.9%), asthenia (48.9%), AST increased (44.7%), nausea (42.6%), ALT increased (42.6%), vomiting (36.2%) and diarrhea (31.9%). Grade 3 and 4 AEs related to SIM were observed in 63.8 % and 29.8 % of pts, respectively, while serious AEs (SAE) related to SIM were reported in 40.4%. The most common SAEs (reported in > 5% pts) irrespective of relatedness to treatment were infusion related reaction (14.9%), pyrexia (6.4%) and hydronephrosis (6.4%). One Grade 5 event occurred, which was unrelated to treatment. Conclusions: SIM in combination with ATZ demonstrated an acceptable safety profile in pts with R/M cervical SCC. The anti-tumor activity compares favorably to the approved PD-1 inhibitors in this setting and supports further exploration of IL-2v and checkpoint inhibition in this patient population of high unmet medical need. Clinical trial information: NCT03386721.

BACKGROUND Osimertinib is a third-generation, irreversible tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations. A phase 3 trial compared first-line osimertinib with other EGFR-TKIs in patients with EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC). The trial showed longer progression-free survival with osimertinib than with the comparator EGFR-TKIs (hazard ratio for disease progression or death, 0.46). Data from the final analysis of overall survival have not been reported. METHODS In this trial, we randomly assigned 556 patients with previously untreated advanced NSCLC with an EGFR mutation (exon 19 deletion or L858R allele) in a 1:1 ratio to receive either osimertinib (80 mg once daily) or one of two other EGFR-TKIs (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily, with patients receiving these drugs combined in a single comparator group). Overall survival was a secondary end point. RESULTS The median overall survival was 38.6 months (95% confidence interval [CI], 34.5 to 41.8) in the osimertinib group and 31.8 months (95% CI, 26.6 to 36.0) in the comparator group (hazard ratio for death, 0.80; 95.05% CI, 0.64 to 1.00; P = 0.046). At 3 years, 79 of 279 patients (28%) in the osimertinib group and 26 of 277 (9%) in the comparator group were continuing to receive a trial regimen; the median exposure was 20.7 months and 11.5 months, respectively. Adverse events of grade 3 or higher were reported in 42% of the patients in the osimertinib group and in 47% of those in the comparator group. CONCLUSIONS Among patients with previously untreated advanced NSCLC with an EGFR mutation, those who received osimertinib had longer overall survival than those who received a comparator EGFR-TKI. The safety profile for osimertinib was similar to that of the comparator EGFR-TKIs, despite a longer duration of exposure in the osimertinib group. (Funded by AstraZeneca; FLAURA ClinicalTrials.gov number, NCT02296125.).

Background Most patients with small-cell lung cancer (SCLC) have extensive-stage disease at presentation, and prognosis remains poor. Recently, immunotherapy has demonstrated clinical activity in extensive-stage SCLC (ES-SCLC). The CASPIAN trial assessed durvalumab, with or without tremelimumab, in combination with etoposide plus either cisplatin or carboplatin (platinum-etoposide) in treatment-naive patients with ES-SCLC. Methods This randomised, open-label, phase 3 trial was done at 209 sites across 23 countries. Eligible patients were adults with untreated ES-SCLC, with WHO performance status 0 or 1 and measurable disease as per Response Evaluation Criteria in Solid Tumors, version 1.1. Patients were randomly assigned (in a 1:1:1 ratio) to durvalumab plus platinum-etoposide; durvalumab plus tremelimumab plus platinum-etoposide; or platinum-etoposide alone. All drugs were administered intravenously. Platinum-etoposide consisted of etoposide 80-100 mg/m(2) on days 1-3 of each cycle with investigator's choice of either carboplatin area under the curve 5-6 mg/mL per min or cisplatin 75-80 mg/m(2) (administered on day 1 of each cycle). Patients received up to four cycles of platinum-etoposide plus durvalumab 1500 mg with or without tremelimumab 75 mg every 3 weeks followed by maintenance durvalumab 1500 mg every 4 weeks in the immunotherapy groups and up to six cycles of platinum-etoposide every 3 weeks plus prophylactic cranial irradiation (investigator's discretion) in the platinum-etoposide group. The primary endpoint was overall survival in the intention-to-treat population. We report results for the durvalumab plus platinumetoposide group versus the platinum-etoposide group from a planned interim analysis. Safety was assessed in all patients who received at least one dose of their assigned study treatment. This study is registered at ClinicalTrials.gov, NCT03043872, and is ongoing. Findings Patients were enrolled between March 27, 2017, and May 29, 2018. 268 patients were allocated to the durvalumab plus platinum-etoposide group and 269 to the platinum-etoposide group. Durvalumab plus platinumetoposide was associated with a significant improvement in overall survival, with a hazard ratio of 0.73 (95% CI 0.59-0.91; p=0.0047]); median overall survival was 13.0 months (95% CI 11.5-14.8) in the durvalumab plus platinum-etoposide group versus 10.3 months (9.3-11.2) in the platinum-etoposide group, with 34% (26.9-41.0) versus 25% (18.4-31.6) of patients alive at 18 months. Any-cause adverse events of grade 3 or 4 occurred in 163 (62%) of 265 treated patients in the durvalumab plus platinum-etoposide group and 166 (62%) of 266 in the platinumetoposide group; adverse events leading to death occurred in 13 (5%) and 15 (6%) patients. Interpretation First-line durvalumab plus platinum-etoposide significantly improved overall survival in patients with ES-SCLC versus a clinically relevant control group. Safety findings were consistent with the known safety profiles of all drugs received. Copyright (C) 2019 Elsevier Ltd. All rights reserved.

BACKGROUND Osimertinib is an oral, third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations. We compared osimertinib with standard EGFR-TKIs in patients with previously untreated, EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC). METHODS In this double-blind, phase 3 trial, we randomly assigned 556 patients with previously untreated, EGFR mutation-positive (exon 19 deletion or L858R) advanced NSCLC in a 1: 1 ratio to receive either osimertinib (at a dose of 80 mg once daily) or a standard EGFR-TKI (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily). The primary end point was investigator-assessed progression-free survival. RESULTS The median progression-free survival was significantly longer with osimertinib than with standard EGFR-TKIs (18.9 months vs. 10.2 months; hazard ratio for disease progression or death, 0.46; 95% confidence interval [CI], 0.37 to 0.57; P<0.001). The objective response rate was similar in the two groups: 80% with osimertinib and 76% with standard EGFR-TKIs (odds ratio, 1.27; 95% CI, 0.85 to 1.90; P = 0.24). The median duration of response was 17.2 months (95% CI, 13.8 to 22.0) with osimertinib versus 8.5 months (95% CI, 7.3 to 9.8) with standard EGFR-TKIs. Data on overall survival were immature at the interim analysis (25% maturity). The survival rate at 18 months was 83% (95% CI, 78 to 87) with osimertinib and 71% (95% CI, 65 to 76) with standard EGFR-TKIs (hazard ratio for death, 0.63; 95% CI, 0.45 to 0.88; P = 0.007 [nonsignificant in the interim analysis]). Adverse events of grade 3 or higher were less frequent with osimertinib than with standard EGFR-TKIs (34% vs. 45%). CONCLUSIONS Osimertinib showed efficacy superior to that of standard EGFR-TKIs in the first-line treatment of EGFR mutation-positive advanced NSCLC, with a similar safety profile and lower rates of serious adverse events.