Luyun, Ronnie F.

7532 Background: Mantle Cell Lymphoma (MCL) is characterized by t(11;14) resulting in over expression of cyclin D1, a member of the phosphatidylinosital 3-kinase (PI3K) pathway. Temsirolimus is a novel inhibitor of the mammalian target of rapamycin (mTOR) kinase. Previous studies with weekly temsirolimus at a dose of 250mg demonstrated a 38% overall response rate in 35 patients (JCO 23 (23); 5347–56, 2005). Thrombocytopenia was frequently observed and was dose limiting. The current study tested whether low-doses (25mg) of temsirolimus could produce a similar overall response rate (ORR) with less toxicity. Methods: Eligible patients had biopsy proven cyclin D1 positive MCL and had relapsed or were refractory to therapy. Patients received temsirolimus 25mg IV weekly as a single agent. Patients were restaged after 1 cycle (4 doses), after 3 cycles, and every 3 cycles thereafter. Patients with a tumor response after 6 cycles were eligible to continue drug for a total of 12 or 2 cycles after complete remission (CR) and then were observed without maintenance. The goal was to achieve an ORR of at least 20%. Results: Twenty-nine patients were enrolled between March and August 2005. Twenty-two patients have completed therapy. One patient with a major protocol violation on cycle-1 and one ineligible patient were excluded, leaving 27 evaluable patients. The ORR was 41% (11/27), with 1 CR and 10 PRs. Early evaluation of TTP showed a median of 5.5 months (95% CI: 3.3–7.7) and the duration of response for the 11 responders was 6.2 months (95% CI: 3.6 to not yet reached). These results compare favorably with the 6.5 months and 6.9 months, respectively, found in previous trials that used 250 mg. The median dose delivered per month was 80 mg (range, 10–100 mg). Sixteen (59%) of patients required a dose reduction. The median time on treatment was 4.4 months (95% CI, 3.3–7.7). The incidence of grade 3 and 4 thrombocytopenia was 12% and 0%, respectively. One patient experienced grade 5 infection without neutropenia, which was considered unrelated to CCI-779. Conclusions: Single agent CCI-779 at a dose of 25mg has anti-tumor activity in relapsed MCL similar to the 250 mg dose. This study indicates that combinations of temsirolimus with other agents should be feasible. [Table: see text]

7547 Background: Sorafenib is a multikinase inhibitor with single-agent activity in previously treated NSCLC. In an effort to evaluate its single agent activity in previously untreated NSCLC, the NCCTG undertook a front-line “window of opportunity” study. Materials and Methods: Patients with stage IIIB (pleural effusion) or stage IV NSCLC received sorafenib dosed at 400 mg BID continuously, with a cycle defined as 4 weeks. Patients were evaluated weekly during the first 2 cycles with those who progressed rapidly going on to receive standard chemotherapy. Based on a two-stage Fleming design, if only at most 1 confirmed response was observed in the first 20 patients enrolled to stage I, the regimen would be considered ineffective. If 2 or more responses were observed, the study would proceed to stage 2 and accrue an additional 22 patients. If 5 or more confirmed responses were observed, the regimen would be recommended for further testing. Results: The study did not meet the stage I efficacy criteria (only 1 confirmed partial response in the first 20 patients) and was permanently closed after enrolling 25 evaluable patients [15 females, 10 males; 4 stage IIIB, 21 stage IV; median age 67 (45–85)]. 2 patients are still receiving treatment (14 and 15 months). No grade 3 or higher hematologic adverse events were observed. Thirteen (52%) patients had a grade 3 non-hematologic adverse event with fatigue (20%), diarrhea (8%), and dyspnea (8%) being the most common. There was one grade 4 pulmonary hemorrhage. A total of 3 (12%) PRs; and 7 (28%) SD were observed in the 25 patients 7 (28%) patients were progression- free at 24 weeks. Median survival and median time to progression were 8.8 and 2.9 months respectively. Conclusion: While the pre- specified efficacy endpoints were not met, the objective response rate of 12% and median survival of 8.8 months suggest that single agent sorafenib has activity similar to two-drug combinations. The feasibility and utility of the “window of opportunity” design in estimating the activity of novel compounds was demonstrated. Finally, the single-agent activity of sorafenib argues for combination studies with standard chemotherapy agents. No significant financial relationships to disclose.

PurposeMantle cell lymphoma (MCL) is characterized by a t(11;14) resulting in overexpression of cyclin D1 messenger RNA. This study tested whether temsirolimus (previously known as CCI-779), an inhibitor of the mammalian target of rapamycin kinase that regulates cyclin D1 translation, could produce tumor responses in patients with MCL.Patients and MethodsPatients with relapsed or refractory MCL were eligible to receive temsirolimus 250 mg intravenously every week as a single agent. Patients with a tumor response after six cycles were eligible to continue drug for a total of 12 cycles or two cycles after complete remission, and were then observed without maintenance.ResultsThirty-five patients were enrolled and were assessable for toxicity; one patient had MCL by histology but was cyclin D1 negative and was ineligible for efficacy. The median age was 70 years (range, 38 to 89 years), 91% were stage 4, and 69% had two or more extranodal sites. Patients had received a median of three prior therapies (range, one to 11), and 54% were refractory to the last treatment. The overall response rate was 38% (13 of 34 patients; 90% CI, 24% to 54%) with one complete response (3%) and 12 partial responses (35%). The median time-to-progression in all patients was 6.5 months (95% CI, 2.9 to 8.3 months), and the duration of response for the 13 responders was 6.9 months (95% CI, 5.2 to 12.4 months). Hematologic toxicities were the most common, with 71% (25 of 35 patients) having grade 3 and 11% (four of 35 patients) having grade 4 toxicities observed. Thrombocytopenia was the most frequent cause of dose reductions but was of short duration, typically resolving within 1 week.ConclusionsSingle-agent temsirolimus has substantial antitumor activity in relapsed MCL. This study demonstrates that agents that selectively target cellular pathways dysregulated in MCL cells can produce therapeutic benefit. Further studies of this agent in MCL and other lymphoid malignancies are warranted.