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LY2603618 is an inhibitor of checkpoint kinase 1 (CHK1), an important regulator of the DNA damage checkpoints. Preclinical experiments analyzed NCI-H2122 and NCI-H441 NSCLC cell lines and in vitro/in vivo models treated with pemetrexed and LY2603618 to provide rationale for evaluating this combination in a clinical setting. Combination treatment of LY2603618 with pemetrexed arrested DNA synthesis following initiation of S-phase in cells. Experiments with tumor-bearing mice administered the combination of LY2603618 and pemetrexed demonstrated a significant increase of growth inhibition of NCI-H2122 (H2122) and NCI-H441 (H441) xenograft tumors. These data informed the clinical assessment of LY2603618 in a seamless phase I/II study, which administered pemetrexed (500 mg/m(2)) and cisplatin (75 mg/m(2)) and escalating doses of LY2603618: 130-275 mg. Patients were assessed for safety, toxicity, and pharmacokinetics. In phase I, 14 patients were enrolled, and the most frequently reported adverse events included fatigue, nausea, pyrexia, neutropenia, and vomiting. No DLTs were reported at the tested doses. The systemic exposure of LY2603618 increased in a dose-dependent manner. Pharmacokinetic parameters that correlate with the maximal pharmacodynamic effect in nonclinical xenograft models were achieved at doses ≥240 mg. The pharmacokinetics of LY2603618, pemetrexed, and cisplatin were not altered when used in combination. Two patients achieved a confirmed partial response (both non-small cell lung cancer), and 8 patients had stable disease. LY2603618 administered in combination with pemetrexed and cisplatin demonstrated an acceptable safety profile. The recommended phase II dose of LY2603618 was 275 mg.

Abstract 5031 Mapatumumab, a fully human monoclonal antibody, targets and activates the TRAIL-R1 receptor. We conducted this randomized, controlled phase II trial to evaluate the efficacy and safety of mapatumumab in combination with bortezomib in subjects with relapsed/refractory MM. Response was evaluated using the Bladé criteria. Patients were required to have a measurable serum and/or urine M-protein and have failed 1 or 2 prior therapies for MM. Patients were excluded if they had received prior bortezomib. Patients were randomly assigned to Arm A, 1.3 mg/m2 bortezomib (days 1, 4, 8, 11) every 21 days; Arm B10, bortezomib + 10 mg/kg mapatumumab (day 1) every 21 days; or Arm B20, bortezomib + 20 mg/kg mapatumumab (day 1) every 21 days. Cycles were repeated every 21 days for a maximum of 17 cycles (1 year), progressive disease or unacceptable toxicity. Subjects with complete response (CR) were treated for an additional 2 cycles after documentation of CR (not to exceed 17) and then followed. A total of 104 subjects from 4 countries were randomly assigned to the treatment arms. The addition of mapatumumab to bortezomib did not increase the response rate, progression-free survival (PFS) or duration of response compared to bortezomib alone. Adverse events were generally balanced across treatment groups; there was no evidence that mapatumumab exacerbated toxicities associated with bortezomib. As expected, the most common toxicities were hematological and peripheral neuropathies. The results do not support further evaluation of mapatumumab in combination with bortezomib in patients with advanced MM. Additional trials of mapatumumab in other indications are on-going. Arm A (n= 35) Arm B10 (n=33) Arm B20 (n=36) CR 0 0 2 PR 18 10 17 CR + PR n (%) 18 (51.4) 10 (30.3) p=0.08a 19 (52.8) p=0.91b Median PFS mo (95% CI) 8.7 (7.6, 10.0) 4.7 (2.5, 7.4) p=0.29a 5.7 (5.2, 8.9) p=0.21b Median Duration of Response mo (range) 8.5 (6.9, 14.2) 9.3 (3.9, 16.1) p=0.92a 7.6 (4.3, 8.8) p=0.41b a P value for comparison of Arm A with Arm B10 b P value for comparison of Arm A with Arm B20 Disclosures: Gallant: Human Genome Sciences, Inc.: Employment, Equity Ownership. Kumm:Human Genome Sciences, Inc.: Employment, Equity Ownership. Klein:Human Genome Sciences, Inc.: Employment, Equity Ownership.

Two death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5), expressed in a wide variety of cancer cell types including lymphoma, enable TRAIL (TNF related apoptosis inducing ligand), a member of the TNF ligand superfamily, to induce apoptosis. HGS-ETR1 (TRM-1, mapatumumab) is a fully human monoclonal antibody agonistic to TRAIL-R1 with preclinical evidence of anti-tumor activity in vitro and in vivo. We conducted a phase 2 multicenter study of HGS-ETR1 in 40 subjects with relapsed or refractory NHL. Patients were included on the study if they had relapsed/refractory NHL of any histologic subtype, irrespective of the number of previous treatment regimens. HGS-ETR1 was administered at 2 dose levels: 3 mg/kg (8 subjects) or 10 mg/kg (32 subjects) every 21 days in the absence of disease progression or prohibitive toxicity for up to 6 cycles. The primary endpoint was tumor response evaluated with the International Working Group Criteria after every third treatment. Responses were confirmed between 4 and 8 weeks after initial documentation of response. Secondary endpoints included safety and tolerability. The median age of subjects was 62 years (range 32–81) (24M:16F) with an ECOG performance status 0–2. Subjects had received up to 12 previous therapeutic regimens (69% received 3 or more prior regimens). Original histologic classification is presently available for 34 subjects (14 follicular, 7 diffuse large B-cell, 6 mantle cell, 1 small lymphocytic, 2 peripheral T-cell, 1 anaplastic large cell, 3 lymphomas not classified). Preliminary response data are available for all 40 subjects. 3 subjects (8%), all with follicular lymphoma, had clinical responses (1CR, 2PR). Additionally, 12/40 subjects (30%) had stable disease, and the remainder had progressive disease at the time of first evaluation. 8 subjects (7 follicular) remain on study without disease progression for >5 to >13 months. One subject with a PR (special permission) has continued to receive HGS-ETR1 (10 cycles to date). Subjects tolerated therapy well with no subjects discontinuing therapy due to toxicity related to drug. There have been 10 reported SAEs, 2 of which were considered possibly/probably related to HGS-ETR1 administration (shingles, fever). In conclusion, HGS-ETR1 can be safely administered to heavily treated NHL patients. Clinical responses were seen in 3/14 follicular lymphoma subjects to date. Final data for all subjects will be reported at the meeting. These data suggest that HGS-ETR1 has activity in heavily pretreated lymphoma patients and further studies in combination with agents active in lymphoma are justified.

The combination of fludarabine and cyclophosphamide (FC) has been noted to produce a high complete response rates in previously untreated patients with CLL. However, it may be accompanied by increased toxicity. To further evaluate its efficacy and toxicity, a phase III randomized study of FC versus Fludarabine (F) was conducted in patients with previously untreated CLL. The study, which was open to accrual from December 23, 1999 to March 19, 2004, closed with 278 patients enrolled, 141 on the FC arm and 137 on the F arm. Four patients declined to receive protocol treatment, including one who was later found to be ineligible. Five additional patients were also deemed ineligible. All patients with data are included in this analysis (intent to treat). Patients on the FC arm received C 600 mg/m2 iv day 1 and F 20 mg/m2 iv days 1 through 5, followed by filgrastim 5 mg/kg SC starting approximately day 8. Patients randomized to the F arm received F 25 mg/m2 iv days 1 through 5. In April 2004, the ECOG Data Monitoring Committee conducted a planned review at 76% information, and determined that the null hypothesis of no difference in CR rates could be rejected. The Data Monitoring Committee gave permission for the submission of abstracts to ASH. The median age of patients was 62 years (34–86), and the median performance status was 1 (0 to 2). As is expected in CLL, 70% of patients were male (194) and 30% were female (83). At study entry, 56% of cases were Rai stages, 0,1 or 2, while 44% were in stage 3 or 4. 57% of patients received the maximum of 6 cycles of therapy. Toxicity data is available on 127 CF and 125 F patients. There were two deaths due to infection with grade 3 or 4 neutropenia (one in each arm). In the CF arm, 17% of patients suffered grade 4 or higher non-hematologic toxicities, while in the F alone arm, 13% had higher grade toxicities (p= 0.48). Additionally, 17% of patients in the FC arm suffered infections versus 11% in the F alone arm (p= 0.21). Response data was available on 246 of the 278 patients. In the FC arm (125 cases), 28 patients achieved CR (22.4%), 60 patients achieved PR (48.0%) for a total of 88 objective responses (70.0%). In contrast, on the F alone arm (121 cases), there were 7 CRs (5.8%), 53 PRs (43.8%) for a total of 60 objective responses (49.6%). The Fisher exact test for the difference in CR rates gives a p-value of 0.0002, while the test for difference in OR rate was 0.001. Currently, 235 patients are alive and 42 have died. Among the 229 patients with information on time to progression, 131 are alive without progression, 78 have progression, and 20 have died without progression. 58 of the 78 with progressive disease remain alive. The preliminary estimates of the median progression free survival time are 41.0 months for the FC arm, and 17.7 months for the F alone arm ( p