Deficient homologous recombination DNA repair appears to cluster sarcoma patients sensitive to trabectedin (ET-743, Yondelis ® ) Maki RG, Taron M, van Oosterom AT, Schöffski P, Tercero JC, Fernandez Sousa-Faro JM, Jimeno JM, Rosell R Memorial Sloan Kettering Cancer Center, New York, NY; Hospital Germans Trias i Pujol, Badalona, Barcelona, SPAIN UZ Gasthuisberg, Leuven, BELGIUM PharmaMar Research and Development, Madrid, SPAIN
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Deficient homologous recombination DNA repair appears to cluster sarcoma patients sensitive to trabectedin (ET-743, Yondelis ® ) Maki RG, Taron M, van.
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Deficient homologous recombination DNA repair appears to cluster sarcoma patients sensitive to trabectedin (ET-743, Yondelis®)
Maki RG, Taron M, van Oosterom AT, Schöffski P, Tercero JC, Fernandez Sousa-Faro JM, Jimeno JM, Rosell R
Memorial Sloan Kettering Cancer Center, New York, NY; Hospital Germans Trias i Pujol, Badalona, Barcelona, SPAIN
UZ Gasthuisberg, Leuven, BELGIUMPharmaMar Research and Development, Madrid, SPAIN
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E. turbinata
Introduction
ET-743 (trabectidin, Yondelis®) is a marine-derived compound in phase II-III development for solid tumors Binds to the minor groove of DNA Interacts with transcription factors and DNA binding proteins Disorganizes of the microtubule network Perturbs the cell cycle Interferes with DNA repair pathways
Van Kesteren et al. Anticancer Drugs. 2002; 13:381
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ET-743 induces long-lasting responses and tumor control in a clinically relevant proportion of patients.
26%29%OS > 2 years (percent)
10.110.3MEDIAN OS (months)
22%20%PFS > 6 months
15 (24%)41 (22%)TUMOR CONTROL
5 (8%)13 (7%)SD
4 (6%)14 (8%)MR
6 (10%)14 (8%)PR
Dox / Ifos Resistant (n=63)Full Cohort (n=183)
PARAMETER
JA López et al. Proc. ASCO 2003; Abstr. 3293A. Le Cesne et al, JCO 2005; 23:576
ET-743 sarcoma program: combined phase II results
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Supervivencia Global – ET- 743 STSMedian Survival 10.3 months
29% of pts alive > 2 yrs
ET-743 phase II sarcoma program: Overall survival
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Identify and validate molecular markers that correlate with sensitivity or resistance to ET-743
– Select the group of STS patients who will most benefit from ET-743
Marker +
Marker -
Objective
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• Human STS cell lines explanted from chemotherapy-naïve patients• 12 low passage sarcoma cell lines sensitive or resistant to ET-743 underwent
gene expression profile (CNIO Oncochip; > 6700 cancer related genes)
STS cell lines
10nM ET-743
0h 6h 12h 24h 72h
MOLECULAR PROFILE OF ET-743
I. Identification of genes in vitro associated with ET-743 sensitivity or
resistance
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51EWING SARCOMASR2910
150.4OSTEOSARCOMASR0312
440.7LIPOSARCOMA SR2103/B
450.7LIPOSARCOMA SR2103/A
>3000.5LIPOSARCOMASW872
>3009LEIOMYOSARCOMALS0904
60
10
not done
>300
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21.5
Doxorubicin
(nM)
>100WILMS TUMORRS0306
1EWING SARCOMAA673
>100
>100
1
0.4
ET-743
(nM)
MPNST
MPNST
FIBROUS TUMOR
LEIOMYOSARCOMA
TUMOR HISTOLOGY
SR0406
SR2410
SR2205
CA1010
CELL LINE
Chemotherapy sensitivity profile of low passage sarcoma cell lines
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Genes differentially expressed in ET-743 sensitive and resistant cell lines
• Cell cycle control – TP53
• Inhibition of transcription and the DNA damage response– JUNB, ATF3, CS-1, SAT, ID2, GADD45B
• DNA repair– BRCA1, XPD, RAD17, p31, p53DINP1
9Takebayashi Y. et al. Nature Med 2001; 7:961
II. DNA repair genes appear central to the function of ET-743: gene deletion experiments
Intactnucleotide
excision repairincreases
cytotoxicity
Deficientdouble stranded
break repairincreases
cytotoxicity
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III. Examining genes involved in DNA repair and how they are implicated in
patient responses to ET-743
• Source material: tumor samples from 45 heavily pre-treated STS patients, subsequently treated with ET-743
• Analyze genes important in DNA repair by mRNA expression and / or analysis of single nucleotide polymorphisms (SNPs)
(a) NER pathway: ERCC1 and XPD mRNA expression and SNP analysis
(b) BRCA1 mRNA expression
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# Pts PR MR SD(*) PD
45 5 1 14 25
53 patients, 8 not evaluable;Median Duration of PR or MR: 13.3 months
(*) 4 / 14 SD achieved PFS > 6 mo 10 / 45 PD achieved PFS > 6 mo
Best ET-743 response in patients providing tumor samples
Comparison of this cohort to the larger cohort of analyzed patients
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Paraffin embedded
tumor tissue
RNA extraction DNA extraction
Quantitation ofRNA expression level
Identification ofpolymorphic DNA
alleles
Reverse transcriptionQ-RT-PCR
Allele discriminationRT-PCR
Gln
NTC
Gln/Gln
Lys/Gln
Lys/Lys
Lys
Gln XPD 751 Gln
Lys XPD 751 Gln
Lys XPD 751 Lys
Experimental design
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Polymorphism
Patients
PR
Lys751Lys
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3 Asp312Asp 15 3
Gln751Gln 5 0 Asn312Asn 7 0
There is a trend in the association between Lys751Lys and Asp312Asp genotypes in XPD gene and better clinical response to ET-743 in sarcoma patients (but p=NS by Fisher’s exact test).
XPD polymorphisms associated with responses to ET-743
Total population: 11.8 monthsPhase II pivotal: 10.3 months
PFS > 6 month rate:
BRCA1 < median: 41 %BRCA1 > median: 6 %
Total population : 26 %Phase II pivotal: 20 %
p = 0.02p = 0.06
Low
Low
SurvivalPFS
HighHigh
Kaplan-Meier survival curves by BRCA1 expression
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Conclusions
• Preclinical analysis of cell lines sensitive or resistant to ET-743 identifies a set of genes that underscores the importance of DNA repair (intact NER) in the mechanism of action of ET-743.
• Low expression of BRCA1 is associated with better objective response, higher rate of progression free survival at 6 months, and a statistically significant improved median survival of sarcoma patients treated with ET-743.
• High expression levels of XPD or ERCC1 may be associated with improved clinical outcome on ET-743
• Lys751Lys and Asp312Asp genotypes in the XPD gene also appear to be associated with a higher rate of response to ET-743.
• Analysis of a larger group of tumors from patients sensitive and resistant to ET-743 will be necessary to confirm the relationship between DNA repair genes and ET-743 sensitivity.