A phase I/II study of KW-2478, an Hsp90 inhibitor, in combination with bortezomib in patients with relapsed/refractory multiple myeloma

Background:

KW-2478 is a novel non-ansamycin Hsp90 inhibitor with modest single-agent activity in relapsed/refractory myeloma but which shows synergistic antimyeloma activity with bortezomib (BTZ) in preclinical studies. This study determined the safety, preliminary clinical activity, and pharmacokinetics of KW-2478, an Hsp90 inhibitor, in combination with BTZ in patients with relapsed/refractory multiple myeloma (MM).

Methods:

Phase I dose escalation determined the recommended phase II dose (RP2D) of KW-2478 plus BTZ, which was then used during phase II.

Results:

The maximum tolerated dose was not reached during phase I and the RP2D was KW-2478 175 mg m⁻² plus BTZ 1.3 mg m⁻² on days 1, 4, 8, and 11 every 3 weeks. In the efficacy evaluable phase I/II population treated at the RP2D (n=79), the objective response rate was 39.2% (95% confidence interval: 28.4–50.9%), clinical benefit rate 51.9% (40.4–63.3%), median progression-free survival 6.7 (5.9-not reached (NR)) months, and median duration of response 5.5 (4.9-NR) months. In the phase I/II safety population (n=95), the most frequently observed treatment-related grade 3/4 adverse events were diarrhoea, fatigue, and neutropenia (each in 7.4% of patients), and nausea and thrombocytopenia (each in 5.3%).

Conclusions:

KW-2478 plus BTZ was well tolerated with no apparent overlapping toxicity in patients with relapsed/refractory MM. The antimyeloma activity of KW-2478 in combination with BTZ as scheduled in this trial appeared relatively modest; however, the good tolerability of the combination would support further exploration of alternate dosing schedules and combinations.

Accelerated R-COP: a pilot study for the treatment of advanced low grade lymphomas that has a high complete response rate

This pilot study tested the hypothesis that dose intensity/dose density treatment may improve the response rate and remission duration in patients with advanced low grade lymphomas. ten patients with low grade lymphomas: follicular lymphoma grades I and II, marginal zone lymphoma, and small cell lymphocytic lymphoma with progressive disease were studied. Patients had an ECOG performance of 0-2, and Stage III and IV disease. Both untreated and previously treated patients with progressive disease were eligible. Patients received a combination of rituximab 375 mg/m(2), cyclophosphamide 1000 mg/m(2), and vincristine 1.4 mg/m(2) (up to a maximal dose of 2 mg), administered by intravenous infusion every two weeks, for ten treatments. Prednisone 50 mg was administered every other day orally for thirty days and then tapered over the next thirty days. Granulocyte colony stimulating factor (G-CSf) was administered on days seven to ten following each cycle of chemotherapy. After 5 and 10 cycles, patients were evaluated for response that included imaging with Ct and pet scans. A total of 10 patients (7 untreated and 3 previously treated) were enrolled into this pilot study between may 2003 and July 2004. Untreated patients received an average of 8.3 cycles of therapy (range 5 to 10 cycles). Seven of 7 untreated patients achieved a complete response (CR), and 5 had not relapsed as of 32-43 months later. Previously treated patients received an average of 9.3 cycles of therapy (range 6 to 12 cycles). One of three previously treated patients achieved a complete response and has no evidence of relapse at 29 months. the other two heavily pretreated patients achieved partial responses, lasting 2 and 5 months. Toxicity was mild consisting mainly of parasthesias requiring attenuation of the vincristine dose. There were no instances of neutropenic fever requiring hospitalization. This program is well tolerated with a high CR rate, and may serve as a basis for future trials.

Anti-tumor activity of partially HLA-matched irradiated blood mononuclear cells in patients with advanced malignancies

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Background: We previously demonstrated the safety and efficacy of HLA-haploidentical blood mononuclear cells (MNCs) administered in the absence of preparative therapy to patients with metastatic renal cell carcinoma (RCC) (J Clin Oncol 21:3785–91.2003). The efficacy of this therapy is evaluated further in patients with advanced malignancies. Methods: Patients with advanced malignancies who had HLA- haploidentical donors were enrolled. Donors underwent 12–15 L leukapheresis. MNCs were processed by irradiation (25 Gy) and immediately infused. Disease evaluation was undertaken every 8 weeks. Repeat infusions were given every 8 weeks until disease progression. Results: 30 patients with diverse diagnoses, including 9 patients with a hematological malignancy were treated. Three of 13 patients with RCC had disease response, and 1 of 2 patients with melanoma had a mixed response. A patient with imatinib mesylate-refractory chronic myelogenous leukemia (CML) had a transient response. A patient with refractory acute myelogenous leukemia (AML) had disease response in conjunction with therapy. Treatment was associated with minimal toxicity and radiographic responses in patients with RCC did not occur until after 2–3 treatments. Host CD8+ cells reactive with the Pr-1 peptide of proteinase 3 were induced in association with disease response in a patient with AML. Additional studies identifying disease targets and mechanisms by which infusion of irradiated HLA-haploidentical cells are associated with disease response are ongoing. Conclusions: Disease response is seen with irradiated allogeneic MNCs administered outside the context of hematopoietic stem-cell transplantation. Evidence for anti-tumor activity is seen in isolated patients with RCC, melanoma, CML and AML. The temporal nature of the response in RCC in combination with the very limited survival of the infused cells raises the possibility of induction of a host-mediated anti-tumor effect. This hypothesis is supported by induction of host CD8+ T cells reactive with a tumor-associated peptide in a patient with AML. Given the lack of toxicity, broad availability of related haploidentical donors and the relative low financial cost, this form of cellular therapy should be developed further.

No significant financial relationships to disclose.