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Initial testing (stage 1) of M6620 (formerly VX-970), a novel ATR inhibitor, alone and combined with cisplatin and melphalan, by the Pediatric Preclinical Testing Program.

ABSTRACT: BACKGROUND:M6620 is a novel inhibitor of the DNA damage repair enzyme ATR, and has potentiated the activity of cisplatin and irinotecan in non-small cell lung cancer and colon cancer xenografts, respectively. PROCEDURES:M6620 was tested in vitro at concentrations ranging from 1.0 nM to 10.0 ?M and at 75 nM in combination with cisplatin or melphalan. M6620 was tested against 24 solid tumor xenografts alone and in combination with cisplatin. Cisplatin was administered intraperitoneally on days 1 and 8 at a dose of 5 mg/kg. M6620 was administered intravenously on days 2 and 9 at 20 mg/m2 approximately 16 hr after cisplatin. RESULTS:The median relative IC50 (rIC50 ) value for M6620 was 0.19 ?M (range 0.03-1.38 ?M). M6620 reduced the mean IC50 of cisplatin and melphalan by 1.48- and 1.95-fold, respectively. M6620 as a single agent in vivo induced significant differences in event-free survival (EFS) distribution in 5 of 24 (21%) solid tumor xenografts, but induced no objective responses. Cisplatin as a single agent induced significant differences in EFS distribution compared to control in 18 of 24 (75%) solid tumor xenografts. Three objective responses to cisplatin were observed. The M6620 and cisplatin combination induced significant differences in EFS distribution compared to control in 21 of 24 (88%), with four objective responses. CONCLUSIONS:M6620 showed modest potentiation of cisplatin and melphalan activity for some cell lines. M6620 showed little single-agent activity and the addition of M6620 to cisplatin significantly prolonged time to event for a minority of tested xenografts across several histologies.

SUBMITTER: Kurmasheva RT

PROVIDER: S-EPMC5876726 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Initial testing (stage 1) of M6620 (formerly VX-970), a novel ATR inhibitor, alone and combined with cisplatin and melphalan, by the Pediatric Preclinical Testing Program.

Kurmasheva Raushan T RT Kurmashev Dias D Reynolds C Patrick CP Kang Min M Wu Jianwrong J Houghton Peter J PJ Smith Malcolm A MA

Pediatric blood & cancer 20170917 2

<h4>Background</h4>M6620 is a novel inhibitor of the DNA damage repair enzyme ATR, and has potentiated the activity of cisplatin and irinotecan in non-small cell lung cancer and colon cancer xenografts, respectively.<h4>Procedures</h4>M6620 was tested in vitro at concentrations ranging from 1.0 nM to 10.0 μM and at 75 nM in combination with cisplatin or melphalan. M6620 was tested against 24 solid tumor xenografts alone and in combination with cisplatin. Cisplatin was administered intraperitonea ...[more]

PMID: 28921800

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Project description:PurposePreclinical studies demonstrated that ATR inhibition can exploit synthetic lethality (eg, in cancer cells with impaired compensatory DNA damage responses through ATM loss) as monotherapy and combined with DNA-damaging drugs such as carboplatin.Patients and methodsThis phase I trial assessed the ATR inhibitor M6620 (VX-970) as monotherapy (once or twice weekly) and combined with carboplatin (carboplatin on day 1 and M6620 on days 2 and 9 in 21-day cycles). Primary objectives were safety, tolerability, and maximum tolerated dose; secondary objectives included pharmacokinetics and antitumor activity; exploratory objectives included pharmacodynamics in timed paired tumor biopsies.ResultsForty patients were enrolled; 17 received M6620 monotherapy, which was safe and well tolerated. The recommended phase II dose (RP2D) for once- or twice-weekly administration was 240 mg/m2. A patient with metastatic colorectal cancer harboring molecular aberrations, including ATM loss and an ARID1A mutation, achieved RECISTv1.1 complete response and maintained this response, with a progression-free survival of 29 months at last assessment. Twenty-three patients received M6620 with carboplatin, with mechanism-based hematologic toxicities at higher doses, requiring dose delays and reductions. The RP2D for combination therapy was M6620 90 mg/m2 with carboplatin AUC5. A patient with advanced germline BRCA1 ovarian cancer achieved RECISTv1.1 partial response and Gynecologic Cancer Intergroup CA125 response despite being platinum refractory and PARP inhibitor resistant. An additional 15 patients had RECISTv1.1 stable disease as best response. Pharmacokinetics were dose proportional and exceeded preclinical efficacious levels. Pharmacodynamic studies demonstrated substantial inhibition of phosphorylation of CHK1, the downstream ATR substrate.ConclusionTo our knowledge, this report is the first of an ATR inhibitor as monotherapy and combined with carboplatin. M6620 was well tolerated, with target engagement and preliminary antitumor responses observed.

Project description:Purpose Our preclinical work identified depletion of ATR as a top candidate for topoisomerase 1 (TOP1) inhibitor synthetic lethality and showed that ATR inhibition sensitizes tumors to TOP1 inhibitors. We hypothesized that a combination of selective ATR inhibitor M6620 (previously VX-970) and topotecan, a selective TOP1 inhibitor, would be tolerable and active, particularly in tumors with high replicative stress. Patients and Methods This phase I study tested the combination of M6620 and topotecan in 3-week cycles using 3 + 3 dose escalation. The primary end point was the identification of the maximum tolerated dose of the combination. Efficacy and pharmacodynamics were secondary end points. Results Between September 2016 and February 2017, 21 patients enrolled. The combination was well tolerated, which allowed for dose escalation to the highest planned dose level (topotecan 1.25 mg/m2, days 1 to 5; M6620 210 mg/m2, days 2 and 5). One of six patients at this dose level experienced grade 4 thrombocytopenia that required transfusion, a dose-limiting toxicity. Most common treatment-related grade 3 or 4 toxicities were anemia, leukopenia, and neutropenia (19% each); lymphopenia (14%); and thrombocytopenia (10%). Two partial responses (≥ 18 months, ≥ 7 months) and seven stable disease responses ≥ 3 months (median, 9 months; range, 3 to 12 months) were seen. Three of five patients with small-cell lung cancer, all of whom had platinum-refractory disease, had a partial response or prolonged stable disease (10, ≥ 6, and ≥ 7 months). Pharmacodynamic studies showed preliminary evidence of ATR inhibition and enhanced DNA double-stranded breaks in response to the combination. Conclusion To our knowledge, this report is the first of an ATR inhibitor-chemotherapy combination. The maximum dose of topotecan plus M6620 is tolerable. The combination seems particularly active in platinum-refractory small-cell lung cancer, which tends not to respond to topotecan alone. Phase II studies with biomarker evaluation are ongoing.

Project description:BackgroundRetrospective studies suggest that conditioning therapy with busulfan plus melphalan could result in longer progression-free survival compared with melphalan alone in patients with multiple myeloma undergoing autologous haemopoietic cell transplantation (auto-HCT). We aimed to test this hypothesis in a randomised trial.MethodsThe primary objective of the study was to compare progression-free survival with conditioning of busulfan plus melphalan with melphalan alone in patients with multiple myeloma. Patients with newly diagnosed multiple myeloma who were eligible for cell transplantation, aged 70 years or younger, with at least stable disease, were randomly assigned (1:1) to treatment. Patients received either busulfan plus melphalan, with a test dose of busulfan 32 mg/m2 followed by pharmacokinetically adjusted doses on days -7, -6, -5, and -4 to achieve a target daily area under the curve (AUC) of 5000 mmol-minute and melphalan 70 mg/m2 per day on days -2 and -1 (total melphalan dose 140 mg/m2), or a melphalan dose of 200 mg/m2 on day -2. Randomisation was performed via a Clinical Trial Conduct Website at the University of Texas MD Anderson Cancer Center. The accrual is complete and final results are presented here. The study is registered with ClinicalTrials.gov, number NCT01413178.FindingsBetween Oct 12, 2011, and March 22, 2017, 205 patients were assessed for eligibility and randomly assigned to treatment. The primary analysis of progression-free survival was measured in 202 patients who received treatment: 104 patients in the busulfan plus melphalan group and 98 patients in the melphalan alone group. 90 days after auto-HCT, 102 (98%) of 104 patients given busulfan plus melphalan and 95 (97%) of 98 patients given melphalan alone achieved partial response or better. The median follow-up in the busulfan plus melphalan group was 22·6 months (IQR 15·2-47·1) and 20·2 months (IQR 8·8-46·6) in the melphalan alone group. Median progression-free survival was 64·7 months (32·9-64·7) with busulfan plus melphalan versus 43·5 months (19·9-not estimated) with melphalan alone (hazard ratio 0·53 [95% CI 0·30-0·91]; p=0·022). There were no treatment-related deaths by day 100 in either group. Grade 2-3 mucositis was observed in 77 (74%) of 104 patients in the busulfan plus melphalan group versus 14 (14%) of 98 patients in the melphalan alone group.InterpretationThese findings, if confirmed in other ongoing studies, suggest that busulfan plus melphalan could replace melphalan alone as the conditioning regimen for auto-HCT in patients with newly diagnosed myeloma.FundingThis study was funded in part by the National Institutes of Health (NIH) through MD Anderson's Cancer Center Support Grant (CA016672).

Dataset Information

Initial testing (stage 1) of M6620 (formerly VX-970), a novel ATR inhibitor, alone and combined with cisplatin and melphalan, by the Pediatric Preclinical Testing Program.

Publications

Initial testing (stage 1) of M6620 (formerly VX-970), a novel ATR inhibitor, alone and combined with cisplatin and melphalan, by the Pediatric Preclinical Testing Program.

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