Phase I study of peposertib and avelumab with or without palliative radiotherapy in patients with advanced solid tumors

INTRODUCTION

We report results from a phase I, three-part, dose-escalation study of peposertib, a DNA-dependent protein kinase inhibitor, in combination with avelumab, an immune checkpoint inhibitor, with or without radiotherapy in patients with advanced solid tumors.

MATERIALS AND METHODS

Peposertib 100-400 mg twice daily (b.i.d.) or 100-250 mg once daily (q.d.) was administered in combination with avelumab 800 mg every 2 weeks in Part A or avelumab plus radiotherapy (3 Gy/fraction × 10 days) in Part B. Part FE assessed the effect of food on the pharmacokinetics of peposertib plus avelumab. The primary endpoint in Parts A and B was dose-limiting toxicity (DLT). Secondary endpoints were safety, best overall response per RECIST version 1.1, and pharmacokinetics. The recommended phase II dose (RP2D) and maximum tolerated dose (MTD) were determined in Parts A and B.

RESULTS

In Part A, peposertib doses administered were 100 mg (n = 4), 200 mg (n = 11), 250 mg (n = 4), 300 mg (n = 6), and 400 mg (n = 4) b.i.d. Of DLT-evaluable patients, one each had DLT at the 250-mg and 300-mg dose levels and three had DLT at the 400-mg b.i.d. dose level. In Part B, peposertib doses administered were 100 mg (n = 3), 150 mg (n = 3), 200 mg (n = 4), and 250 mg (n = 9) q.d.; no DLT was reported in evaluable patients. Peposertib 200 mg b.i.d. plus avelumab and peposertib 250 mg q.d. plus avelumab and radiotherapy were declared as the RP2D/MTD. No objective responses were observed in Part A or B; one patient had a partial response in Part FE. Peposertib exposure was generally dose proportional.

CONCLUSIONS

Peposertib doses up to 200 mg b.i.d. in combination with avelumab and up to 250 mg q.d. in combination with avelumab and radiotherapy were tolerable in patients with advanced solid tumors; however, antitumor activity was limited.

CLINICALTRIALS

GOV IDENTIFIER

NCT03724890.

A single-arm, multicenter, phase II trial of osimertinib in patients with epidermal growth factor receptor exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations

BACKGROUND

For patients with stage IV non-small-cell lung cancer with epidermal growth factor receptor (EGFR) exon 19 deletions and exon 21 L858R mutations, osimertinib is the standard of care. Investigating the activity and safety of osimertinib in patients with EGFR exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations is of clinical interest.

PATIENTS AND METHODS

Patients with stage IV non-small-cell lung cancer with confirmed EGFR exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations were eligible. Patients were required to have measurable disease, an Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate organ function. Patients were required to be EGFR tyrosine kinase inhibitor-naive. The primary objective was objective response rate, and secondary objectives were progression-free survival, safety, and overall survival. The study used a two-stage design with a plan to enroll 17 patients in the first stage, and the study was terminated after the first stage due to slow accrual.

RESULTS

Between May 2018 and March 2020, 17 patients were enrolled and received study therapy. The median age of patients was 70 years (interquartile range 62-76), the majority were female (n = 11), had a performance status of 1 (n = 10), and five patients had brain metastases at baseline. The objective response rate was 47% [95% confidence interval (CI) 23% to 72%], and the radiographic responses observed were partial response (n = 8), stable disease (n = 8), and progressive disease (n = 1). The median progression-free survival was 10.5 months (95% CI 5.0-15.2 months), and the median OS was 13.8 months (95% CI 7.3-29.2 months). The median duration on treatment was 6.1 months (range 3.6-11.9 months), and the most common adverse events (regardless of attribution) were diarrhea, fatigue, anorexia, weight loss, and dyspnea.

CONCLUSIONS

This trial suggests osimertinib has activity in patients with these uncommon EGFR mutations.

Durvalumab (durva) after chemoradiotherapy (CRT) in unresectable, stage III, EGFR mutation-positive (EGFRm) NSCLC: A post hoc subgroup analysis from PACIFIC

8541

Background: Standard of care for patients (pts) with unresectable (UR) stage III NSCLC is the ‘PACIFIC regimen’, based on data from the phase 3 placebo (pbo)-controlled trial where consolidation durva following CRT improved overall survival (OS; hazard ratio [HR], 0.68 [95% CI, 0.53, 0.87]) and progression-free survival (PFS; HR, 0.52 [95% CI 0.42, 0.65]), in an all-comer population. However, the benefit of immunotherapy (IO) in pts with EGFRm stage III NSCLC is unclear. We report a post hoc exploratory efficacy and safety analysis from 35 pts with EGFRm NSCLC from the PACIFIC trial (NCT02125461). Methods: Pts with stage III UR-NSCLC, WHO performance status (PS) 0/1 and no progression after ≥2 cycles platinum-based concurrent CRT were randomized 2:1 (1–42 days post CRT) to receive durva (10mg/kg IV q2w for up to 1 year) or pbo, stratified by age, sex, and smoking history; enrollment was not restricted by oncogenic driver gene mutation status or PD-L1 expression. Primary endpoints: PFS (BICR; RECIST v1.1) and OS; key secondary endpoints: objective response rate (ORR) and safety. Treatment effects for the EGFRm subgroup were estimated using an unstratified Cox proportional hazard model; medians were estimated using the Kaplan–Meier method. Statistical analyses were exploratory. Data cut-off (DCO) for the EGFRm subgroup efficacy analysis was 11 January 2021. Results: Of 713 pts randomized, 35 had EGFRm NSCLC based on local testing (durva n = 24, pbo n = 11). In the EGFRm subgroup, more pts in the pbo vs durva arm were male (73% vs 54%), had stage IIIA disease (64% vs 46%), PS 0 (64% vs 54%) and received pre-CRT induction chemotherapy (36% vs 8%). More pts in the durva arm were Asian (63% vs 55%) and had PD-L1 on < 25% tumor cells (67% vs 36%); median age was consistent across arms. At DCO, median duration of follow-up for survival was 42.7 months (range, 3.7–74.3 months) for all randomized pts in the subgroup. Median PFS was 11.2 months (95% CI 7.3, 20.7) with durva vs 10.9 months (95% CI 1.9, not evaluable [NE]) with pbo; HR 0.91 (95% CI 0.39, 2.13). Median OS was 46.8 months (95% CI 29.9, NE) with durva vs 43.0 months (95% CI 14.9, NE) with pbo; HR 1.02 (95% CI 0.39, 2.63). ORR was 26.1% (95% CI, 10.2, 48.4) and 18.2% (95% CI 2.3, 51.8) with durva and pbo, respectively. The safety profile for durva was consistent with the overall population. In the durva and pbo subgroup arms, radiation pneumonitis was reported in 42% vs 36% of pts, and pneumonitis was reported in 17% vs 18% of pts (1 grade 3, pbo arm), respectively. Conclusions: In this post hoc exploratory analysis of 35 pts, PFS and OS outcomes with durva were similar to pbo in the EGFRm population, with wide CIs. The benefit of IO in this population remains unclear. The ongoing LAURA study (NCT03521154) is investigating the efficacy and safety of maintenance osimertinib in pts with locally advanced EGFRm stage III UR-NSCLC with no progression after CRT. Clinical trial information: NCT02125461.

Outcomes with durvalumab after chemoradiotherapy in stage IIIA-N2 non-small-cell lung cancer: an exploratory analysis from the PACIFIC trial

Background

The phase III PACIFIC trial (NCT02125461) established consolidation durvalumab as standard of care for patients with unresectable, stage III non-small-cell lung cancer (NSCLC) and no disease progression following chemoradiotherapy (CRT). In some cases, patients with stage IIIA-N2 NSCLC are considered operable, but the relative benefit of surgery is unclear. We report a post hoc, exploratory analysis of clinical outcomes in the PACIFIC trial, in patients with or without stage IIIA-N2 NSCLC.

Materials and methods

Patients with unresectable, stage III NSCLC and no disease progression after ≥2 cycles of platinum-based, concurrent CRT were randomized 2 : 1 to receive durvalumab (10 mg/kg intravenously; once every 2 weeks for up to 12 months) or placebo, 1-42 days after CRT. The primary endpoints were progression-free survival (PFS; assessed by blinded independent central review according to RECIST version 1.1) and overall survival (OS). Treatment effects within subgroups were estimated by hazard ratios (HRs) from unstratified Cox proportional hazards models.

Results

Of 713 randomized patients, 287 (40%) had stage IIIA-N2 disease. Baseline characteristics were similar between patients with and without stage IIIA-N2 NSCLC. With a median follow-up of 14.5 months (range: 0.2-29.9 months), PFS was improved with durvalumab versus placebo in both patients with [HR = 0.46; 95% confidence interval (CI), 0.33-0.65] and without (HR = 0.62; 95% CI 0.48-0.80) stage IIIA-N2 disease. Similarly, with a median follow-up of 25.2 months (range: 0.2-43.1 months), OS was improved with durvalumab versus placebo in patients with (HR = 0.56; 95% CI 0.39-0.79) or without (HR = 0.78; 95% CI 0.57-1.06) stage IIIA-N2 disease. Durvalumab had a manageable safety profile irrespective of stage IIIA-N2 status.

Conclusions

Consistent with the intent-to-treat population, treatment benefits with durvalumab were confirmed in patients with stage IIIA-N2, unresectable NSCLC. Prospective studies are needed to determine the optimal treatment approach for patients who are deemed operable.

•

The PACIFIC trial established durvalumab after CRT as standard of care for unresectable, stage III NSCLC.

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The optimum multimodal treatment strategy for patients with potentially resectable, stage IIIA-N2 NSCLC is unknown.

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Survival benefit with durvalumab was observed in patients with stage IIIA-N2, unresectable NSCLC in this post hoc analysis.

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Durvalumab after CRT also exhibited a manageable safety profile in this subpopulation from PACIFIC.

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Studies of surgical vs. non-surgical strategies are needed to establish the best approach for potentially operable patients.

Clinical definition of acquired resistance to immunotherapy in patients with metastatic non-small-cell lung cancer

Acquired resistance (AR) to programmed cell death protein 1/programmed death-ligand 1 [PD-(L)1] blockade is frequent in non-small-cell lung cancer (NSCLC), occurring in a majority of initial responders. Patients with AR may have unique properties of persistent antitumor immunity that could be re-harnessed by investigational immunotherapies. The absence of a consistent clinical definition of AR to PD-(L)1 blockade and lack of uniform criteria for ensuing enrollment in clinical trials remains a major barrier to progress; such clinical definitions have advanced biologic and therapeutic discovery. We examine the considerations and potential controversies in developing a patient-level definition of AR in NSCLC treated with PD-(L)1 blockade. Taking into account the specifics of NSCLC biology and corresponding treatment strategies, we propose a practical, clinical definition of AR to PD-(L)1 blockade for use in clinical reports and prospective clinical trials. Patients should meet the following criteria: received treatment that includes PD-(L)1 blockade; experienced objective response on PD-(L)1 blockade (inclusion of a subset of stable disease will require future investigation); have progressive disease occurring within 6 months of last anti-PD-(L)1 antibody treatment or rechallenge with anti-PD-(L)1 antibody in patients not exposed to anti-PD-(L)1 in 6 months.

A micro-organosphere potency assay for adoptive T-cell therapy

e15027

Background: Lung cancer is the leading cause of death worldwide. Metastatic lung cancer patients often relapse or grow refractory to chemotherapy, radiotherapy, and checkpoint inhibitors. Adoptive T cell therapy (ACT) has been garnering more attention due to longitudinal complete responses. Tumor resections from patients harbor tumor-infiltrating lymphocytes (TILs) which can be cultured ex vivo and assessed for tumor reactivity before infusion. This generally follows a patient lymphodepletion regimen which allows the transferred T cells an optimal environment to proliferate and survive in the patient. TIL ACT can produce complete responses – rarely ever observed using traditional onco-therapy – in metastatic melanoma patients. However, while TILs specific to the neo-antigens expressed by tumor cells can be expanded ex vivo, this observed specificity is low in the clinic. Researchers have attempted to solve this by priming ex vivo expanded T cells with antigen-presenting cells previously pulsed with peptides representative of the neo-antigen repertoire of the matched tumor, but have rarely observed complete responses, likely due to current biomarkers for T cell activity poorly predicting anti-tumor cytotoxicity. To date there has been no acceptable potency assay for manufactured TILs, a requirement by the FDA for approval to use them in the clinic. Thus, the need to assess potency of ex vivo engineered T-cells against matched tumor cells is evident. Methods: We have developed a novel diagnostic immune-oncology (IO) pipeline, which uses a membrane-microfluidic platform to culture patient-derived tumor micro-organospheres (MOs) in extracellular matrix droplets. MOs can be rapidly established following patient tumor sample acquisition through biopsies or resection, and preserve the stromal cell populations in the original tumor microenvironment, as characterized by both flow cytometry and single-cell RNA-seq. An automated imaging assay was further established to robustly quantify the amount of immune-induced apoptosis of tumor cells in the MOs by patient-matched TILs, which is highly specific and yields minimal background. Results: We find that this method is not only amenable to high-throughput microscopy, but the larger surface-area-to-volume ratio of micro-organospheres also allows greater TIL infiltration and interaction with tumor cells. The resulting highly-sensitive assay requires far fewer input immune and tumor cells to achieve robust, clinical grade sensitivity response, making it the first clinically feasible assay for testing personalized TIL potency. Conclusions: The MO IO technology is currently being used for assessing clinical efficacy of manufactured TIL products for an upcoming ACT trial for non-small cell lung cancer patients. This technology also provides a companion to TIL ACT, CAR T therapy, and other immunotherapies, for which the ability to predict clinical potency is generally lacking.

Five-year survival outcomes with durvalumab after chemoradiotherapy in unresectable stage III NSCLC: An update from the PACIFIC trial

8511

Background: In the placebo-controlled Phase III PACIFIC trial of patients with unresectable Stage III NSCLC whose disease had not progressed after platinum-based concurrent chemoradiotherapy (cCRT), durvalumab improved overall survival (OS) (stratified hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.53–0.87; p=0.0025; data cutoff [DCO] Mar 22, 2018) and progression-free survival (PFS) (stratified HR 0.52, 95% CI 0.42–0.65; p<0.0001; DCO Feb 13, 2017) based on the DCOs used for the primary analyses, and the degree of benefit remained consistent in subsequent updates. Durvalumab was associated with a manageable safety profile, and did not detrimentally affect patient-reported outcomes, compared with placebo. These findings established consolidation durvalumab after CRT (the ‘PACIFIC regimen’) as the standard of care in this setting. We report updated, exploratory analyses of OS and PFS, assessed approximately 5 years after the last patient was randomized. Methods: Patients with WHO PS 0/1 (and any tumor PD-L1 status) whose disease did not progress after cCRT (≥2 overlapping cycles) were randomized (2:1) 1–42 days following cCRT (total prescription radiotherapy dose typically 60–66 Gy in 30–33 fractions) to receive 12 months’ durvalumab (10 mg/kg IV every 2 weeks) or placebo, stratified by age (<65 vs ≥65 years), sex, and smoking history (current/former smoker vs never smoked). The primary endpoints were OS and PFS (blinded independent central review; RECIST v1.1) in the intent-to-treat (ITT) population. HRs and 95% CIs were estimated using stratified log-rank tests in the ITT population. Medians and OS/PFS rates at 60 months were estimated with the Kaplan–Meier method. Results: Overall, 709/713 randomized patients received treatment in either the durvalumab (n/N=473/476) or placebo (n/N=236/237) arms. The last patient had completed study treatment in May 2017. As of Jan 11, 2021 (median follow-up duration of 34.2 months in all patients; range, 0.2–74.7 months), updated OS (stratified HR 0.72, 95% CI 0.59–0.89; median 47.5 vs 29.1 months) and PFS (stratified HR 0.55, 95% CI 0.45–0.68; median 16.9 vs 5.6 months) remained consistent with the results from the primary analyses. The 60-month OS rates were 42.9% and 33.4% with durvalumab and placebo, respectively, and 60-month PFS rates were 33.1% and 19.0%, respectively. Updated treatment effect estimates for patient subgroups will be presented. Conclusions: These updated survival analyses, based on 5-year data from PACIFIC, demonstrate robust and sustained OS plus durable PFS benefit with the PACIFIC regimen. An estimated 42.9% of patients randomized to durvalumab remain alive at 5 years and approximately a third remain both alive and free of disease progression. Clinical trial information: NCT02125461.

Phase II randomized trial of first-line pembrolizumab and vorinostat in patients with metastatic NSCLC (mNSCLC)

9567

Background: Histone deacetylase inhibitors may enhance tumor immunogenicity through various mechanisms including induced expression of T cell chemokines. A previous phase I trial demonstrated the combination of pembrolizumab (P) with vorinostat (V) in mNSCLC was well tolerated with signals of activity in ICI-pretreated pts. We initiated a randomized trial in the first-line setting with the primary objective to determine if the combination had superior ORR compared to pembrolizumab monotherapy. Methods: Pts with treatment-naïve mNSCLC and PD-L1 expression ≥ 1% were eligible. Pts were randomized open-label 1:1 to receive P 200 mg IV q3 wk as monotherapy [Arm A] or P 200 mg IV q3 wk plus V 400 mg PO daily [Arm B]. The primary endpoint was overall response rate (ORR). Secondary endpoints included DOR, PFS and OS. Tumor biopsies were collected both pre- and on-treatment (day 15-21) for analysis of CD8+ TIL, scored using a 0-3 scale in tumor beds. Here we report results after a preplanned interim analysis for efficacy, with accrual ongoing to a planned total of 39 patients per arm. Results: Between 7/2017 – 1/2019, 49 pts were enrolled, with 47 pts evaluable for response (24 in Arm A and 23 in Arm B). Median age was 69 (range 47 - 87), 49% female, ECOG PS 0/1 in 11%/89%. PD-L1 TPS was ≥50% in 13/24 (54%) of pts in Arm A, and in 13/23 (57%) of pts in Arm B. The most common TRAEs in Arm A included diarrhea (13%), fatigue (8%), and pruritus (8%). 3 pts in Arm A experienced grade ≥ 3 irAEs (including 1 each of grade 3 hepatitis, pneumonitis, and rash). The most common TRAEs in Arm B included anorexia (43%), fatigue (43%), nausea (35%) and increased creatinine (35%). 1 pt in Arm B experienced grade ≥ 3 irAE (1 grade 3 pneumonitis). Pre-treatment CD8+ TIL were not significantly different between Arm A and Arm B (p = 0.85) with the majority of tumors in both arms having a low TIL score of 1 (65% Arm A and 73.7% Arm B). A significant increase from pre-treatment to on-treatment TIL scores was seen in both Arm A (p = 0.001) and Arm B (p = 0.002). The ORR in Arm B pts with low pre-treatment TIL (score = 1) pts was substantially higher (66.7%) than in Arm A (33.3%), suggesting the combination may be especially beneficial against low TIL tumors. Conclusions: The combination arm had a considerably higher ORR compared to pembrolizumab monotherapy, with a manageable toxicity profile. The combination of pembrolizumab plus vorinostat in mNSCLC warrants further investigation. Clinical trial information: NCT02638090 . [Table: see text]

Interim results from the OPTIMAL trial: A phase II clinical trial of combination nivolumab, ipilimumab, and taxane in patients with untreated metastatic non-small cell lung cancer (NSCLC)

e21683

Background: Combination chemo-immunotherapy is a well-established frontline therapeutic option for treatment naïve NSCLC. Dual immune checkpoint blockade (ICB) with nivolumab (nivo) and ipilimumab (ipi) has demonstrated improved clinical outcomes compared with chemotherapy alone in this setting. Combination dual ICB with low-dose chemotherapy may have advantages of preventing early disease progression and potentiating immunogenic response to treatment. Methods: We are conducting a single arm phase II clinical trial of nivo 360 mg IV Q3 weeks, ipi 1 mg/kg IV Q6 weeks, and weekly paclitaxel 80 mg/m2 IV on d1 and d8 of a 21 day cycle in ECOG 0-1 patients (pts) with treatment naïve NSCLC. Paclitaxel is stopped after a total of 4-6 cycles. The primary endpoint of the trial is progression free survival (PFS) with secondary endpoints of safety and objective response rate (ORR) by independent radiologic review. Interim results are presented from the first 23 evaluable pts, of a planned sample size of 49. Results: 23 pts were enrolled and evaluable with a mean age 63.8 years, 56.5% ECOG 0, 87% current/previous smoking history, and 70% adenocarcinoma. PDL1 score for < 1%, 1-49%, ³ 50% was seen in 9 (39.1%), 4 (17.4%), and 10 (43.5%) pts, respectively. Median time of follow up was 6.5 months (range 1.4–15.0). Partial response was observed in 14 pts, stable disease was seen in 8 pts, and 1 pt progressed during cycle 1, resulting in an ORR of 61%. Grade 3 or higher toxicity at least possibly attributed to study treatment was seen in 47.8% of 23 AE evaluable patients, of which included 4 cases of secondary adrenal insufficiency. Other toxicity rates were as expected for the respective agents. Conclusions: This is the first trial to evaluate weekly paclitaxel with nivo plus ipi in pts with untreated NSCLC. This regimen has demonstrated highly encouraging clinical activity with a manageable toxicity profile. The study is ongoing and updated results will be presented at the annual meeting. Clinical trial information: NCT03573947.

Non-pneumonitis immune-mediated adverse events (imAEs) with durvalumab in patients with unresectable stage III NSCLC (PACIFIC)

9048

Background: The phase 3 PACIFIC trial established durvalumab (durva) after chemoradiotherapy (CRT) as SoC for pts with unresectable stage III NSCLC. We report exploratory analyses to characterize non-pneumonitis (np) imAEs that occurred with durva in PACIFIC. Methods: PACIFIC was a double blind trial of pts without disease progression after platinum-based concurrent CRT (≥2 cycles). Pts were randomized 2:1 to receive durva 10 mg/kg or placebo (pbo) IV q2w for ≤12 months, stratified by age, sex and smoking history. We characterized the time to onset, duration, and management/outcomes of np imAEs and their association with (1) baseline pt/disease factors and (2) AEs (excluding all-cause pneumonitis). Results: Of 709 treated pts, 19% and 11% experienced imAEs and np imAEs of any grade, respectively; proportionally more had np imAEs with durva (71/475; 15%) vs pbo (5/234; 2%). Thyroid disorders (54/475; 11%), rash/dermatitis (9/475; 2%), and diarrhea/colitis (5/475; 1%) were the most common np imAEs with durva; rash/dermatitis had the shortest time to onset (Table). Among durva treated pts with np imAEs, 11% had grade 3/4 np imAEs, 41% had np imAEs that resolved, and none had fatal np imAEs; interventions included endocrine replacement therapy (73%), systemic corticosteroids (34%), high dose corticosteroids (16%), and discontinuation (10%). There were no apparent differences in baseline factors between pts with or without np imAEs. Durva had a broadly manageable safety profile irrespective of the occurrence of np imAEs. However, a higher proportion of durva treated pts with vs without np imAEs experienced all-cause, grade 3/4 events (41% vs 29%); none were fatal (excl. pneumonitis). Conclusions: Np imAEs occurred infrequently in PACIFIC, but were more common with durva vs pbo; thyroid disorders and rash/dermatitis were the most common np imAEs. Of durva treated pts with np imAEs, 11% experienced np imAEs of grade 3/4. Overall, np imAEs were broadly manageable and did not lead to high rates of discontinuation, and no association with baseline factors was seen, suggesting this should not deter use of durva in eligible pts. Clinical trial information: NCT02125461. [Table: see text]

Outcomes with durvalumab by tumour PD-L1 expression in unresectable, stage III non-small-cell lung cancer in the PACIFIC trial

BACKGROUND

In the PACIFIC trial, durvalumab significantly improved progression-free and overall survival (PFS/OS) versus placebo, with manageable safety, in unresectable, stage III non-small-cell lung cancer (NSCLC) patients without progression after chemoradiotherapy (CRT). We report exploratory analyses of outcomes by tumour cell (TC) programmed death-ligand 1 (PD-L1) expression.

PATIENTS AND METHODS

Patients were randomly assigned (2:1) to intravenous durvalumab 10 mg/kg every 2 weeks or placebo ≤12 months, stratified by age, sex, and smoking history, but not PD-L1 status. Where available, pre-CRT samples were tested for PD-L1 expression (immunohistochemistry) and scored at pre-specified (25%) and post hoc (1%) TC cut-offs. Treatment-effect hazard ratios (HRs) were estimated from unstratified Cox proportional hazards models (Kaplan-Meier-estimated medians).

RESULTS

In total, 713 patients were randomly assigned, 709 of whom received at least 1 dose of study treatment durvalumab (n = 473) or placebo (n = 236). Some 451 (63%) were PD-L1-assessable: 35%, 65%, 67%, 33%, and 32% had TC ≥25%, <25%, ≥1%, <1%, and 1%-24%, respectively. As of 31 January 2019, median follow-up was 33.3 months. Durvalumab improved PFS versus placebo (primary-analysis data cut-off, 13 February 2017) across all subgroups [HR, 95% confidence interval (CI); medians]: TC ≥25% (0.41, 0.26-0.65; 17.8 versus 3.7 months), <25% (0.59, 0.43-0.82; 16.9 versus 6.9 months), ≥1% (0.46, 0.33-0.64; 17.8 versus 5.6 months), <1% (0.73, 0.48-1.11; 10.7 versus 5.6 months), 1%-24% [0.49, 0.30-0.80; not reached (NR) versus 9.0 months], and unknown (0.59, 0.42-0.83; 14.0 versus 6.4 months). Durvalumab improved OS across most subgroups (31 January 2019 data cut-off; HR, 95% CI; medians): TC ≥ 25% (0.50, 0.30-0.83; NR versus 21.1 months), <25% (0.89, 0.63-1.25; 39.7 versus 37.4 months), ≥1% (0.59, 0.41-0.83; NR versus 29.6 months), 1%-24% (0.67, 0.41-1.10; 43.3 versus 30.5 months), and unknown (0.60, 0.43-0.84; 44.2 versus 23.5 months), but not <1% (1.14, 0.71-1.84; 33.1 versus 45.6 months). Safety was similar across subgroups.

CONCLUSIONS

PFS benefit with durvalumab was observed across all subgroups, and OS benefit across all but TC <1%, for which limitations and wide HR CI preclude robust conclusions.

Nivolumab versus docetaxel in previously treated advanced non-small-cell lung cancer (CheckMate 017 and CheckMate 057): 3-year update and outcomes in patients with liver metastases

Background

Long-term data with immune checkpoint inhibitors in non-small-cell lung cancer (NSCLC) are limited. Two phase III trials demonstrated improved overall survival (OS) and a favorable safety profile with the anti-programmed death-1 antibody nivolumab versus docetaxel in patients with previously treated advanced squamous (CheckMate 017) and nonsquamous (CheckMate 057) NSCLC. We report results from ≥3 years' follow-up, including subgroup analyses of patients with liver metastases, who historically have poorer prognosis among patients with NSCLC.

Patients and methods

Patients were randomized 1 : 1 to nivolumab (3 mg/kg every 2 weeks) or docetaxel (75 mg/m2 every 3 weeks) until progression or discontinuation. The primary end point of each study was OS. Patients with baseline liver metastases were pooled across studies by treatment for subgroup analyses.

Results

After 40.3 months' minimum follow-up in CheckMate 017 and 057, nivolumab continued to show an OS benefit versus docetaxel: estimated 3-year OS rates were 17% [95% confidence interval (CI), 14% to 21%] versus 8% (95% CI, 6% to 11%) in the pooled population with squamous or nonsquamous NSCLC. Nivolumab was generally well tolerated, with no new safety concerns identified. Of 854 randomized patients across both studies, 193 had baseline liver metastases. Nivolumab resulted in improved OS compared with docetaxel in patients with liver metastases (hazard ratio, 0.68; 95% CI, 0.50-0.91), consistent with findings from the overall pooled study population (hazard ratio, 0.70; 95% CI, 0.61-0.81). Rates of treatment-related hepatic adverse events (primarily grade 1-2 liver enzyme elevations) were slightly higher in nivolumab-treated patients with liver metastases (10%) than in the overall pooled population (6%).

Conclusions

After 3 years' minimum follow-up, nivolumab continued to demonstrate an OS benefit versus docetaxel in patients with advanced NSCLC. Similarly, nivolumab demonstrated an OS benefit versus docetaxel in patients with liver metastases, and remained well tolerated.

Clinical trial registration

CheckMate 017: NCT01642004; CheckMate 057: NCT01673867.

Phase 1, open-label, dose-escalation study of M3814 + avelumab ± radiotherapy (RT) in patients (pts) with advanced solid tumors

TPS3169

Background: DNA-dependent protein kinase (DNA-PK) regulates a key DNA damage response (DDR) pathway for double-strand break (DSB) repair. DNA-PK inhibition augments DNA DSB damage generated by many antitumor therapies, including RT. DNA damage and repair impact the interaction of tumors with the immune system; combining immune checkpoint inhibitors (CPIs) with RT + DDR-targeted agents may modulate the tumor immune microenvironment, enhancing responsiveness to CPIs. M3814 (small molecule selective DNA-PK inhibitor) has demonstrated monotherapy activity in several tumor cell lines, and M3814 + RT combined with avelumab (programmed death ligand 1 mAb) significantly delayed tumor growth vs either agent alone + RT in MC38 syngrafts. This study will evaluate the clinical utility of M3814 combined with avelumab ± RT in pts with advanced solid tumors. Methods: NCT03724890 is a 2-part first-in-man study in adult pts with advanced or metastatic solid tumors. Part A is enrolling pts with measurable/evaluable solid tumors (RECIST v1.1); Part B will enrol pts with primary or metastatic tumor(s) in the lung which is/are amenable to be irradiated. In Part A, M3814 will be given orally twice daily. In Part B, M3814 + TRT will be given once daily, 5 days/wk for 2 wk. In both parts, pts will receive avelumab iv once every 2 wk from Day 1 until disease progression/unacceptable toxicity. Part B will initiate once the Safety Monitoring Committee declares the first dose level of Part A to have acceptable safety/tolerability. Primary objectives are to define the recommended Phase 2 dose (RP2D) of M3814 when combined with avelumab (Part A) and with avelumab + TRT (Part B) via dose-limiting toxicities (DLTs) occurring during the first 3/4 (Part A/B) wk of treatment. Secondary objectives include safety/tolerability, pharmacokinetics, immunogenicity, preliminary antitumor activity (BOR, PFS, OS). Sample size for each part depends on the number of DLTs/dose levels for M3814; dose escalation will be based on a Bayesian logistic regression model with overdose control. Part A aims to include 6–24 pts (≤4 dose levels), Part B 6–18 pts (≤3 dose levels). Recruitment began in Dec 2018. Clinical trial information: NCT03724890.

First subsequent treatment after discontinuation of durvalumab in unresectable, stage III NSCLC patients from PACIFIC

9054

Background: In the phase 3 PACIFIC trial of unresectable, stage III NSCLC patients (pts) without progression after concurrent chemoradiotherapy (cCRT), durvalumab (durva) significantly improved PFS and OS with similar safety compared to placebo (pbo). We performed exploratory analyses to characterize first subsequent treatment (Tx) after discontinuation of durva. Methods: Pts with WHO PS 0/1 and any tumor PD-L1 status were randomized (2:1) 1–42 days after ≥2 cycles of platinum-based cCRT to durva 10 mg/kg IV or pbo Q2W up to 12 months, stratified by age, sex and smoking history. Pts were classified by the use or not of first subsequent Tx and category of first systemic Tx (platinum doublet CT [PDCT], single-agent CT [SCT], immunotherapy [IT] or targeted therapy [TT]). Results: As of Mar 22, 2018, 216/476 (45.4%) and 153/237 (64.6%) in the durva and pbo arms, respectively, had a RECIST-based PFS event per BICR (5.7% and 8.4% due to death). 195 (41.0%) and 128 (54.0%) received first subsequent Tx, most of which were systemic Tx (158 [33.2%] and 109 [46.0%]): PDCT (16.4% and 19.0%), SCT (8.6% and 8.4%), IT (4.2% and 13.5%) or TT (3.8% and 5.1%); 7.8% and 8.0% received RT only. Time to first subsequent therapy or death (TFST) was longer with durva vs pbo (HR 0.58; 95% CI 0.47–0.72; median 21.0 vs 10.4 months). Baseline characteristics of pts with or without first subsequent Tx were similar, and similar across durva or pbo arms. Among pts with systemic Tx, baseline characteristics (including pre-cCRT PD-L1 status) were generally similar, except pts on TT, more of whom were EGFR+ (70.0% vs 0–6.6% of other systemic Tx groups) with commonly associated phenotypes (more females, Asians, non-smokers and non-squamous pts). Best overall response to first systemic Tx will be presented. Conclusions: Due to longer PFS and fewer progression events with durva vs pbo, fewer pts on durva required subsequent Tx and, per TFST, much later. With the exception of IT, use of each subsequent Tx was similar between the durva and pbo arms with PDCT the most common. Baseline characteristics were similar for pts with or without first subsequent Tx and pts who received first systemic Tx, except for pts who received TT, as expected due to their molecular profile.

Clinical responses and survival in Hispanic patients with non-small cell lung cancer treated with immunotherapy compared with non-Hispanic whites

e18109

Background: The main immunotherapy (IMMUNO) trials that led to the approval of these agents for non-small cell lung cancer (NSCLC) accrued a minimum number of Hispanic (HISP) patients (pts) or, in some studies, no HISP pts at all. Additional data is thus needed to validate outcomes in HISP pts with NSCLC treated with IMMUNO. While it is known that genomic profiles and cancer survivals are different between HISP, Non-Hispanic Whites (NHW), and African-Americans; no study has yet looked at differences in IMMUNO outcomes between these populations. Methods: We present data in 436 NSCLC pts treated with IMMUNO at 5 large institutions (3 in the US, 2 in Latin America). The agents evaluated include: nivolumab, pembrolizumab and atezolizumab. 256 pts were HISP and 180 pts were NHW. Most of the pts were treated with single agent therapy as second line (or beyond) while a small group of pts were treated as first line. The primary endpoints of the study were: response rate (ORR), progression free survival (PFS) and overall survival (OS). Results: Among NHW pts, disease control rate (DCR) was 67% for Adenocarcinomas (Adeno) and 46% for squamous cell carcinomas (SQCC). In HISP pts there were no differences in DCR rates between both histologies: 68% for Adeno and 67% SQCC. There were no statistical significant differences among HISP and NHW pts regarding ORR, PFS, OS, and responses according to PD-L1 status. Conclusions: This is the largest publication and comparison of NSCLC immunotherapy outcomes in HISP vs NHW pts. No significant differences were found in the clinical outcomes between these 2 ethnic groups despite expected genomic differences. Pts with actionable mutations were excluded as they usually do not get IMMUNO as first or second line; an approach that might change after IMPOWER 150. These results are comparable to the ones seen in Checkmate and Keynote studies. As expected, higher response rates were seen in first line therapy and pts with PD-L1 (+) status. Further comparisons will be better addressed by a larger prospective study.[Table: see text]

Blood tumor mutational burden (bTMB) and tumor PD-L1 as predictive biomarkers of survival in MYSTIC: First-line durvalumab (D) ± tremelimumab (T) versus chemotherapy (CT) in metastatic (m) NSCLC

9016

Background: MYSTIC, an open-label, Ph3 trial of first-line D (anti-PD-L1) ± T (anti-CTLA-4) vs platinum-based CT, showed an improvement in OS with D vs CT in pts with tumor cell PD-L1 expression ≥25% (PD-L1 TC ≥25%; HR 0.76 [97.54% CI 0.56–1.02], p = 0.036). Exploratory analyses showed bTMB was a predictive biomarker for OS with D±T vs CT. We report further exploratory analyses of OS according to PD-L1 and bTMB. Methods: Immunotherapy/CT-naïve pts with mNSCLC were randomized (1:1:1) to D, D+T or CT. bTMB levels (mut/Mb) were evaluated with the GuardantOMNI platform (Guardant Health), and PD-L1 TC expression with the VENTANA PD-L1 (SP263) IHC assay. Results: D improved OS vs CT in pts with PD-L1 TC ≥25% across bTMB levels (PD-L1 TC ≥25%/bTMB≥20 HR 0.79 [95% CI 0.45, 1.39]; PD-L1 TC ≥25%/bTMB < 20 HR 0.64 [95% CI 0.45, 0.90]). In contrast, D+T improved OS vs CT in pts with bTMB≥20 across different PD-L1 TC expression levels (Table; PD-L1 TC ≥25%/bTMB≥20 HR 0.44 [95% CI 0.23, 0.84]; PD-L1 TC < 1%/bTMB≥20 HR 0.42 [95% CI 0.17, 0.97]). Additional cutoffs and outcomes in subgroups defined by both biomarkers will be presented. Conclusions: These exploratory analyses from MYSTIC support PD-L1 TC expression as an appropriate predictive biomarker for OS with D vs CT, while suggesting bTMB as a predictive biomarker for OS with D+T in mNSCLC. These biomarkers appear to be independent and both may be important for mNSCLC treatment decisions. Interpretation of these data may be limited by small sample sizes; further investigations are warranted. Clinical trial information: NCT02453282. [Table: see text]

Phase I/Ib study of pembrolizumab and vorinostat in patients with metastatic NSCLC (mNSCLC): Updated results

9073

Background: Histone deacetylase inhibitors (HDACi) enhance tumor immunogenicity through several mechanisms and may augment response to immune checkpoint inhibitors (ICI). We report updated results from a phase I/Ib trial testing the combination of oral HDACi vorinostat (V) with PD-1 inhibitor pembrolizumab (P) in mNSCLC. Methods: In phase I, pts with ICI-naïve or ICI-pretreated mNSCLC were treated with P (200mg IV q3 wk) + V (200 or 400 mg PO daily). In phase Ib expansion, pts were required to have progressed on prior ICI treatment. Primary endpoints were safety/tolerability; secondary endpoints included RR, PFS, DOR, and OS. Tissue and blood specimens from pre- and on-treatment were collected for correlative analyses to determine tumor gene expression changes, T cell density and levels of myeloid-derived suppressor cells. Results: Between 3/2016 - 12/2018, Phase I: 13 pts were treated (4 at 200mg, and 9 at 400mg V dose); and Phase Ib: 20 pts were treated. Median age: 68 (range 38-82); Females: 11 (33%); ECOG 1: 31 (94%); and never/former/current smokers: 3/22/8 (9%/67%/24%). PD-L1 expression was < 1% in 8/33 (18%), ≥1-49% in 7/33 (21%), ≥ 50% in 9/33 (27%) and unknown in 11/30 (33%). No DLTs or treatment related deaths were observed. The RP2D was P 200mg and V 400mg. Most common any grade AEs was fatigue (11%) and nausea/vomiting (8%). 2 (6%) patients had treatment discontinued due to toxicity. 30 pts are evaluable for response, 6 ICI-naïve and 24 ICI-pretreated. 4 (13%) had PR (2 confirmed), 16 (53%) had SD, and 10 (33%) had PD for a disease control rate of 67%. In the ICI-pretreated Ib cohort, 3 pts (1 confirmed; 2 unconfirmed) had a PR and 10 had SD (8 confirmed). For ICI-pretreated pts, mPFS was 3.2 and mOS was 7.3 months, and 1-year PFS was 17% (4 pts). For ICI-naïve, mPFS was 7.6 months and mOS was 16 months. CD8 T cell presence in tumor stromal regions was associated with benefit to P + V treatment. Conclusions: P + V were well tolerated. The combination demonstrates preliminary anti-tumor activity despite progression on prior ICI treatment and stromal CD8 T cells may be associated with benefit from P + V treatment. A randomized phase II portion of this study, examining P combined with V vs. placebo in immunotherapy naïve pts, is ongoing. Clinical trial information: NCT02638090.

Three-year overall survival update from the PACIFIC trial

8526

Background: In the phase 3 PACIFIC study of patients with unresectable, Stage III NSCLC without progression after chemoradiotherapy (CRT), durvalumab demonstrated significant improvements versus placebo in the primary endpoints of progression-free survival (HR, 0.52; 95% CI, 0.42–65; P < 0.0001) and overall survival (OS; HR, 0.68; 95% CI, 0.53–0.87; P = 0.00251). Safety was similar and durvalumab had no detrimental effect on patient-reported outcomes. Here, we report 3-year OS rates for all patients randomized in the PACIFIC study. Methods: Patients with WHO PS 0/1 (any tumor PD-L1 status) who received ≥2 cycles of platinum-based CRT were randomized (2:1), 1–42 days following CRT, to receive durvalumab 10 mg/kg intravenously every 2 weeks or placebo, up to 12 months, and stratified by age, sex, and smoking history. OS was analyzed using a stratified log-rank test in the ITT population. Medians and OS rates at 12, 24 and 36 months were estimated by Kaplan-Meier method. Results: In total, 713 patients were randomized of whom 709 received treatment (durvalumab, n = 473; placebo, n = 236). The last patient had completed the protocol-defined 12 months of study treatment in May 2017. As of January 31, 2019 (data cutoff), 48.2% of patients had died (44.1% and 56.5% in the durvalumab and placebo groups, respectively). The median duration of follow-up was 33.3 months (range, 0.2–51.3). Updated OS remained consistent with that previously reported (stratified HR 0.69, 95% CI, 0.55–0.86), with the median not reached (NR; 95% CI, 38.4 months–NR) with durvalumab versus 29.1 months (95% CI, 22.1–35.1) with placebo. The 12-, 24- and 36-month OS rates with durvalumab and placebo were 83.1% versus 74.6%, 66.3% versus 55.3%, and 57.0% versus 43.5%, respectively. After discontinuation, 43.3% and 57.8% in the durvalumab and placebo groups, respectively, received subsequent anticancer therapy (9.7% and 26.6% subsequently received immunotherapy). OS subgroup results will be presented. Conclusions: Updated OS data from PACIFIC, including 3-year survival rates, underscore the long-term clinical benefit with durvalumab following CRT and further establish the PACIFIC regimen as the standard of care in this population. Clinical trial information: NCT02125461.