Analysis of patients with relapsed small cell lung cancer (SCLC) receiving single-agent lurbinectedin in the phase 3 ATLANTIS trial

8524

Background: Lurbinectedin, a selective inhibitor of oncogenic transcription, received accelerated approval from the US FDA in June 2020 as monotherapy (3.2 mg/m2 IV every 21 days) for adults with metastatic SCLC with disease progression on or after platinum-based chemotherapy. This approval was based on the overall response rate (35.2%) and duration of response (DOR; 5.3 months) observed in 105 patients from a phase 2 trial. The ATLANTIS trial (NCT02566993) investigated the combination of lurbinectedin 2.0 mg/m2 IV + doxorubicin (DOX) 40.0 mg/m2 IV versus topotecan or CAV. This post hoc analysis explored the efficacy and safety of single-agent lurbinectedin in patients who completed 10 cycles of the combination and then switched to lurbinectedin monotherapy per protocol. Methods: Eligible patients were ≥18 years of age with limited-stage or extensive-stage SCLC, 1 prior line of platinum-based chemotherapy (PD-1/PD-L1 inhibitors were also permitted), ECOG PS ≤2, and chemotherapy-free interval ≥30 days. Tumor assessments were per an independent review committee (IRC). Results: Patients who completed 10 cycles of lurbinectedin + DOX and switched to lurbinectedin monotherapy (n = 50) had a median age of 61.5 years (range: 43, 77); 62% were male; and 100% had an ECOG PS < 2. The overall median number of cycles was 15 (range: 11, 47) and included a median of 5 (1, 37) cycles on monotherapy. The majority of patients who switched to lurbinectedin monotherapy maintained or improved their tumor response (Table). All 3 patients who achieved a complete response (CR) on combination therapy maintained their CR on monotherapy. Of the 26 patients with a partial response (PR) on combination therapy, 3 (12%) achieved a CR and 15 (58%) maintained their PR. Of the 19 patients with stable disease (SD) on combination therapy, 3 (16%) improved from SD to PR (n = 2) or CR (n = 1) and 8 (42%) maintained SD. The median DOR was 8.3 months (95% CI: 7.1, 11.0). The median overall survival (OS) was 20.7 months (95% CI: 15.7, 24.8). Grade 3/4 hematologic abnormalities based on laboratory assessment included lymphopenia (36%), anemia (16%), thrombocytopenia (12%), neutropenia (12%), and leukopenia (10%). Febrile neutropenia was reported in 4% of patients. Conclusions: Patients with relapsed SCLC in ATLANTIS who completed 10 cycles of lurbinectedin + DOX combination and switched to lurbinectedin monotherapy tended to maintain or improve their tumor response (including an increase in CRs), with favorable OS and DOR and acceptable tolerability with no new safety signals. Clinical trial information: NCT02566993. [Table: see text]

Lurbinectedin in patients with pretreated BRCA1/2-associated metastatic breast cancer: Results from a phase II basket study

1092

Background: Lurbinectedin (L) is a selective inhibitor of oncogenic transcription that leads to cell apoptosis and shows antitumor activity against homologous recombination repair-deficient cell lines. A previous phase II study (Cruz et al. JCO 2018;36:3134-3143) demonstrated antitumor activity in patients (pts) with pretreated metastatic breast cancer (median of 1 prior advanced chemotherapy line) and BRCA1/2-mutated tumors with L 3.5 mg/m2 or 7.0 mg flat dose (equivalent to 4.0 mg/m2) every three weeks [q3wk]). This report focuses on the outcomes in the BRCA1/2-associated breast cancer cohort of a phase II Basket multitumor trial. Methods: This phase II study evaluated L 3.2 mg/m2 1-hour intravenous (i.v.) infusion q3wk in a cohort of 21 female pts with pretreated BRCA1/2-associated breast cancer. The primary efficacy endpoint was ORR according to RECIST v1.1. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), OS and safety. Results: Median age was 45 years (range, 29-73 years). Hormone receptor (HR)+ disease was observed in 76.2% of pts, triple negative disease in 19.0% and HER2+ in 9.5%. BRCA1 and BRCA2 were reported in 47.6% and 52.4% of pts, respectively. Median number of prior lines of chemotherapy for advanced disease was 2 (range, 0-3 lines). Prior poly(ADP-ribose) polymerase inhibitors and platinum compounds had been administered to 23.8% and 47.6% of pts, respectively. Confirmed partial response (PR) was observed in six pts (ORR = 28.6%; 95% CI, 11.3-52.2%). Lurbinectedin was active in both BRCA mutations: four PRs in 11 pts (36.4%) in BRCA2 and two PRs in 10 pts (20.0%) in BRCA1. Median DoR was 8.6 months, median PFS was 4.1 months and median OS was 16.1 months. Stable disease (SD) was observed in ten pts (47.6%), including three pts with unconfirmed response in a subsequent tumor assessment (ORR unconfirmed = 42.9% [95%CI, 21.8-66.0]). Clinical benefit rate (PR + SD≥4 months) was 76.2% (95% CI, 52.8-91.8%). The most common grade 3/4 toxicity was neutropenia (42.9%; grade 4, 23.8%; with no febrile neutropenia). Conclusions: This phase II study met its primary endpoint and confirmed the activity of L in pretreated BRCA1/2-associated breast cancer pts. L 3.2 mg/m2 1-hour i.v. infusion q3wk showed an acceptable, predictable and manageable safety profile. Considering the exploratory aim of this trial as well as previous results in other phase II study, further development of L in this indication is warranted. Clinical trial information: NCT02454972.

First-in-human study of PM14 in patients with advanced solid tumors

3078

Background: PM14 is a new chemical entity that forms DNA adducts which specifically inhibit RNA synthesis and block active transcription of protein-coding genes. Antitumor activity has been demonstrated in vitro in several cell lines (e.g. lung, kidney, prostate), and in vivo in mice bearing xenografted human-derived tumors (soft tissue sarcoma, small cell lung cancer, ovarian, gastric, breast and renal cancer). Methods: Open-label, dose-escalating, phase I trial of PM14 administered as a 3-hour infusion i.v. every 3 weeks (q3wk) in patients (pts) with advanced solid tumors, adequate organ function and ECOG PS score of 0-1. Two schedules were explored: Schedule A (Day 1 [D1], Day 8 [D8]) and Schedule B (D1). Results: 37 pts were treated (Schedule A/B: 28/9 pts). Baseline characteristics of pts (A/B): median age 56/47 years; male 57%/56%; ECOG PS 0: 57%/56%; median of prior lines (range): 3 (1-8)/4 (1-10). Most common tumor types (A + B): STS (n=7 pts), ovarian (n=6), pancreatic (n=4), prostate cancer (n=3). The maximum tolerated dose was 4.5 mg/m2 for A (dose-limiting toxicities [DLTs]: D8 omission due to lack of recovery of lab parameters for re-treatment [n=2 pts]) and 5.6 mg/m2 (DLTs: G4 febrile neutropenia [n=1], G4 transaminase increase [n=1]) for B. The recommended dose (RD) was 3.0 mg/m2 on D1,D8 (A), and 4.5 mg/m2 on D1 (B). No DLTs were present at the RDs. Most common toxicities were hematological abnormalities and transaminase increase. Main toxicities at the RDs are shown below. Antitumor activity comprised stable disease ≥4 months in 7 heavily pretreated pts (6 in A; 1 in B) at all dose levels. Linear pharmacokinetics were observed for PM14 at tested doses (0.25-5.6 mg/m²), with geometric mean (CV%) total plasma clearance 5.9 L/h (88%), volume of distribution 128 L (81%) and median (range) terminal half-life 15.9 h (7.5-34.3 h). Less than 1.6% of administered dose was recovered in urine. Conclusions: RDs were determined for two PM14 schedules in pts with advanced solid tumors. At the RDs, PM14 is well tolerated and has a manageable safety profile. An expansion phase in specific tumor types, with an optional Bayesian continual reassessment method for RD fine-tuning, is ongoing with both schedules.[Table: see text]

Lurbinectedin (LUR) in combination with Irinotecan (IRI) in patients (pts) with advanced endometrial carcinoma

5586

Background: LUR is a new agent that exerts antitumor activity through inhibition of trans-activated transcription and modulation of tumor microenvironment. Preclinical synergism/additivity in combination with IRI has been reported, thus prompting the conduct of this trial. This synergism had been evaluated and recently reported in patients with Small Cell Lung Cancer, with encouraging results (Ponce et al. WCLC, 2020). Methods: Phase I trial to evaluate escalating doses of LUR on Day (D) 1 plus a fixed dose of IRI 75 mg/m2 on D1 and D8 every 3 weeks (q3w) in pts with advanced solid tumors, enrolled following a standard 3+3 dose escalation design. Phase II to expand in selected indications at the Recommended Dose (RD). In this abstract, the cohort of patients with endometrial carcinoma treated at the RD is presented. Results: 21 pts (all female) with endometrial carcinoma were treated at the RD (LUR 2 mg/m2 + IRI 75 mg/m2 + G-CSF); 57% had ECOG PS=1; median age was 64 years (range 34-74); subtype of tumour was split: 67% (14 pts) endometroid, 33% non-endometroid (3 pts serous-papilar, 3 pts clear-cell and 1 pt undifferentiated); median of 2 prior lines (range, 1−7) per pt. Common G1/2 toxicities were nausea, vomiting, fatigue, diarrhea and anorexia; G3/4 hematological toxicities comprised neutropenia (33%), thrombocytopenia (5%) and anemia (38%). Two episodes of febrile neutropenia occurred (9.5%). G3/4 non hematological toxicities consisted of diarrhea (24%), asthenia (19%), nausea (14%) and vomiting (5%), all were transient and manageable. 1 patient (5%) discontinued treatment due to toxicity drug-related (generalized muscular weakness), but no treatment-related deaths were reported. Objective RECIST responses were documented in 4/21 evaluable pts (19%). With 6 pts censored for progression, median PFS was 4.4 months (95% CI 2.1-9.6 months), and PFS at 6 months was 40.4%. The clinical benefit rate (% of pts with Complete Response (CR), Partial Response (PR) or Stable Disease > 4 months) was 43%, and the Disease Control Rate (% of pts with CR, PR or SD) 81%. 3/21 pts (14%) have been more than 12 months on treatment so far. Conclusions: The combination of Lurbinectedin and Irinotecan is active in heavily pretreated patients with endometrial carcinoma. The combination was well-tolerated and consistent with the known safety profile for this combination. Myelosuppression, diarrhea, nausea and asthenia were predictable and manageable. Updated results of this cohort will be presented at the meeting. Clinical trial information: NCT02611024.

Lurbinectedin (LUR) in combination with Irinotecan (IRI) in patients (pts) with advanced solid tumors: Updated results from a phase Ib-II trial

3514

Background: LUR is a novel agent that exerts antitumor activity through inhibition of trans-activated transcription and modulation of tumor microenvironment. Preclinical synergism/additivity in combination with IRI has been reported, thus prompting the conduct of this clinical trial. Methods: Phase Ib-II trial to evaluate escalating doses of LUR on Day (D) 1 plus a fixed dose of IRI 75 mg/m2 on D1 and D8 every 3 weeks (q3w) in pts with advanced solid tumors (+/- G-CSF, if dose-limiting toxicities [DLTs] were neutropenia). Starting dose was LUR 1.0 m/m2 + IRI 75 mg/m2. Results: 77 pts have been treated to date at 5 dose levels, 51 of them at the recommended dose (RD). Baseline characteristics of all 77 pts were: 48% females, 68% ECOG PS=1; median age 57 years (range, 19-75 years); median of 2 prior lines (range, 0−4 lines). The maximum tolerated dose (MTD) was LUR 2.4 mg/m2 + IRI 75 mg/m2 with G-CSF, and the RD was LUR 2.0 mg/m2 + IRI 75 mg/m2 with G-CSF. DLTs in Cycle 1 occurred in 2/3 evaluable pts at the MTD and 3/13 evaluable pts at the RD, and comprised omission of IRI D8 infusion due to grade (G) 3/4 neutropenia (n=3 pts) or G2-4 thrombocytopenia (n=2). At the RD (n=51), common G1/2 non-hematological toxicities were nausea, vomiting, fatigue, diarrhea, anorexia and neuropathy. G3 non-hematological toxicities (diarrhea 10%, fatigue 10%) and G3/4 hematological abnormalities (neutropenia 49%, thrombocytopenia 10%) were transient. Conclusions: The combination of LUR and IRI had acceptable tolerance, with no unexpected toxicities. Transient myelosuppression was dose-limiting. The RD is LUR 2.0 mg/m2 on D1 + IRI 75 mg/m2 on D1 and D8 q3w with G-CSF. Antitumor activity was observed at the RD in SCLC pts, as well as in endometrial carcinoma pts. Hints of activity were also observed in STS pts. Updated results will be presented. Clinical trial information: NCT02611024 . [Table: see text]

Pooled safety analysis of single-agent lurbinectedin versus topotecan (Results from a randomized phase III trial CORAIL and a phase II basket trial)

3635

Background: Lurbinectedin (L), an inhibitor of active transcription, has shown activity in second-line (2L) small cell lung cancer (SCLC) (ASCO 2019). Topotecan (T) is the only approved drug in 2L SCLC and is also used in platinum resistant ovarian cancer (PROC). Methods: This pooled safety analysis includes data from 554 patients (pts) treated with L at 3.2 mg/m2 Day 1 q3wk 1-h (no primary prophylaxis with G-CSF required): 335 with selected solid tumors (9 indications, including 105 pts with SCLC) from a phase II Basket study and 219 with PROC in the phase III CORAIL study. An indirect exploratory comparison (pooled data from CORAIL + Basket) and a direct comparison (data from CORAIL) of L vs. T are presented. Results: Most common adverse events with L were grade 1/2 fatigue, nausea and vomiting. Treatment-related (L/T): dose reductions: 22.9/48.3%, delays: 25.8/52.9%, grade ≥3 serious adverse events (SAEs): 15.0/32.2%, discontinuations: 3.2/5.7%, deaths: 1.3/1.5%, G-CSF use: 23.8/70.1%, and transfusions: 15.9/52.9%. Conclusions: Lurbinectedin has a predictable and manageable safety profile. A significant safety advantage was observed when lurbinectedin was compared with topotecan in the CORAIL trial in terms of hematological toxicities. With the limitations of indirect comparisons, in the pooled safety analysis, fewer lurbinectedin-treated pts had severe hematological toxicities, SAEs, dose adjustments, treatment discontinuations and use of supportive treatments than topotecan-treated pts. Clinical trial information: NCT02421588 and NCT02454972 . [Table: see text]

Efficacy and safety profile of lurbinectedin in second-line SCLC patients: Results from a phase II single-agent trial

8506

Background: Lurbinectedin (L) is a novel anticancer drug that inhibits activated transcription and induces DNA double-strand breaks, leading to apoptosis. Methods: A multicenter phase 2 basket trial assessed the efficacy and safety of L in several cancer types, including small cell lung cancer (SCLC). Primary endpoint was confirmed overall response rate (ORR) by RECIST v.1.1. In the SCLC cohort, a target ORR ≥30% was set. One-hundred and five patients (pts) with ECOG PS 0-2 who had received one prior chemotherapy line were treated with L 3.2 mg/m2 as a 1-hour i.v. infusion on Day 1 q3wk. Results: Median age was 60 years (range, 40-83), 60% were male, ECOG PS 0/1/2 (32%/62%/6%), liver metastasis 41%, history of CNS involvement 3.8%, prior platinum 100%, median chemotherapy-free interval (CTFI): 3.5 (0-16.1) months; prior immunotherapy (IO): 7.6%. Pts received a median of 4 cycles (range, 1-24). Conclusions: L monotherapy is active in second-line SCLC in both resistant and sensitive disease. The acceptable and manageable safety profile is also associated to a convenient treatment administration (Day 1 q3wk). L as second-line treatment in SCLC emerges as a new promising drug for this unmet clinical need. Clinical trial information: NCT02454972. [Table: see text]

Alectinib versus crizotinib in treatment-naive advanced ALK-positive non-small cell lung cancer (NSCLC): Primary results of the global phase III ALEX study

LBA9008

Background: Alectinib, a TKI targeting ALK, has shown robust efficacy in crizotinib-naïve/resistant ALK+ NSCLC. J-ALEX showed superiority of alectinib 300mg BID vs crizotinib in Japanese pts with crizotinib-naïve ALK+ NSCLC (progression-free survival [PFS] HR 0.34, p<0.0001). We report primary results from the ALEX study of first-line alectinib 600mg BID vs crizotinib in advanced ALK+ NSCLC (NCT02075840). Methods: This open-label randomized multicenter phase III study enrolled pts with stage IIIB/IV ALK+ NSCLC, determined by central IHC testing. Eligible pts had ECOG PS 0–2 and no prior systemic therapy for advanced NSCLC. Pts with asymptomatic CNS metastases were allowed. Pts (n=303) were randomized 1:1 to receive alectinib 600mg or crizotinib 250mg BID. Primary endpoint: Investigator (Inv)-assessed PFS (RECIST v1.1), with systematic CNS imaging in all pts. Secondary endpoints included independent review committee (IRC)-assessed PFS, IRC-assessed time to CNS progression (TTP), objective response rate (ORR), overall survival (OS) and safety. Results: At the primary data cut-off (9 Feb 2017), alectinib demonstrated statistically significant superiority vs crizotinib, reducing risk of progression/death by 53% (HR 0.47, 95% CI 0.34–0.65, p<0.0001); alectinib median PFS was not reached (95% CI 17.7–NE) vs crizotinib 11.1 months (95% CI 9.1–13.1). Key secondary endpoints showed superiority for alectinib vs crizotinib, respectively: IRC PFS, HR 0.50 (95% CI 0.36–0.70; p<0.0001); median PFS 25.7 months (95% CI 19.9–NE) vs 10.4 months (95% CI 7.7–14.6); CNS TTP, cause-specific HR of CNS progression 0.16 (95% CI 0.10–0.28; p<0.0001); ORR (Inv) 83% (95% CI 76–89) vs 76% (95% CI 68–82), p=0.09; OS, based on 25% events, HR 0.76 (95% CI 0.48–1.20; p=0.24). Grade 3/4 AEs were less frequent with alectinib, 41%, vs 50% with crizotinib; fatal AEs occurred in 3% vs 5%, respectively. Rates of AEs leading to discontinuation, dose reduction and interruption were lower with alectinib. Conclusions: Alectinib showed superior efficacy and favorable tolerability compared with crizotinib. ALEX results support alectinib as a new standard of care for treatment-naïve ALK+ NSCLC. Funding: F. Hoffmann-La Roche Clinical trial information: NCT02075840.

Alectinib versus crizotinib in treatment-naive advanced ALK-positive non-small cell lung cancer (NSCLC): Primary results of the global phase III ALEX study

The full, final text of this abstract will be available at abstracts.asco.org at 7:30 AM (EDT) on Monday, June 5, 2017, and in the Annual Meeting Proceedings online supplement to the June 20, 2017, issue of the Journal of Clinical Oncology. On site at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

Population pharmacokinetics (popPK) and exposure-response (ER) analyses bridge J-ALEX to the global population with an alectinib (ALC) 600mg bid dosing regimen

e20616

Background: J-ALEX showed superiority of ALC 300mg BID vs crizotinib (CRIZ) in Japanese ALK inhibitor naïve ALK-positive NSCLC patients (pts). PopPK and ER analyses were used to bridge J-ALEX data to the global population to confirm the appropriateness of ALC 600mg BID dose, used in global trials. Methods: The previous popPK analysis (Hsu et al, ASCO 2016) was updated to include PK data from J-ALEX and the ongoing global ALEX study to confirm any significant covariates influencing PK of ALC and major metabolite, M4, using Bayesian feedback analysis. ER analyses from J-ALEX (n=96) investigated the relationship between ALC and progression-free survival (PFS) by a Cox proportional hazards (CPH) analysis and key safety events using logistic regression. Results: The popPK models previously developed for pts who have progressed on, or are intolerant to CRIZ were able to adequately predict ALC and M4 PK in J-ALEX and ALEX. Body weight remained the only significant covariate influencing ALC and M4 PK. Administration of ALC 600mg BID in the global population ensures that ALC and M4 exposures across the body weight range are not inferior to those seen in Japanese pts receiving ALC 300mg BID, while lower doses would result in lower exposures. CPH analysis demonstrated a statistically significant relationship between ALC exposure and PFS in J-ALEX such that one third of pts in J-ALEX may benefit from a higher exposure of ALC (Table). ALC 600mg BID ensures the distribution of achieved exposures maximize the expected PFS benefit while lower ALC exposures could result in reduced efficacy. No significant exposure-safety relationships were identified in J-ALEX consistent with previous analyses conducted following ALC 600mg BID. Conclusions: ALC 600mg BID is the appropriate dose in the global ALK inhibitor naïve population. Clinical trial information: JapicCTI-132316. [Table: see text]