Maxygen Announces Positive Results of MAXY-G34 Phase IIa Study in Breast Cancer Patients
News Jul 15, 2009
Maxygen, Inc. has announced the completion of a Phase IIa clinical study in breast cancer patients in which MAXY-G34 was safe and effective in reducing chemotherapy-induced neutropenia (CIN), a major side effect of myelosuppressive anti-cancer agents.
“We are encouraged by these clinical data and FDA feedback on Maxygen’s proposed development plan for MAXY-G34 in CIN,” said Russell Howard, Maxygen’s Chief Executive Officer.
“These events further confirm that, with the right partnership, a timely and cost effective development pathway to BLA filing can be achieved in 2013. MAXY-G34, with a product profile similar to Neulasta®, could be the 2nd entrant in the multi-billion dollar, long-acting G-CSF market.”
The objectives of this recently completed Phase IIa study were to evaluate safety, tolerability, pharmacokinetics and efficacy of MAXY-G34 in breast cancer patients.
The 35 patient trial included 27 patients receiving MAXY-G34 (doses of 10, 30, 45, 60 or 100 µg/kg) and 8 patients receiving Neulasta® (fixed dose of 6 mg). Both study medications were administered as a single, subcutaneous injection 24 hours post chemotherapy. A highly myelosuppressive TAC chemotherapy regimen was used in the trial.
In the absence of G-CSF treatment, TAC chemotherapy is expected to induce 7-8 days of severe neutropenia [Nabholtz et al, Phase II Study of Docetaxel, Doxorubicin and Cyclophosphamide as First-line Chemotherapy for Metastatic Breast Cancer, Journal of Clinical Oncology (2001)]. The primary efficacy endpoint of the study was duration of severe neutropenia in chemotherapy cycle 1.
In this clinical study, all doses of MAXY-G34 effectively reduced the duration of severe neutropenia (DSN) observed, compared to the above-referenced historical controls. Importantly, no MAXY-G34 patients required rescue therapy due to insufficient efficacy of MAXY-G34.
The mean duration of severe neutropenia for MAXY-G34 dose groups in chemotherapy cycle 1 ranged from 0.8 to 2.2 days, versus 2.0 days in the Neulasta® control group. Data on the primary efficacy endpoint for the MAXY-G34 doses in the range proposed for further study and the Neulasta® control group are included below:
MAXY-G34 was also safe and well-tolerated in this clinical study. The type and incidence of adverse events were consistent with those observed in other G-CSF clinical trials and were comparable between the MAXY-G34 and Neulasta® treatment arms.
No dose relationship was observed with respect to adverse events in the MAXY-G34 groups. No unexpected serious adverse events were noted in any patients. No immunogenicity was detected after six administrations of MAXY-G34 at any dose level.
Maxygen submitted the Phase IIa data as part of a scientific advice briefing package to the United States Food & Drug Administration (FDA) to solicit feedback on key elements of the MAXY-G34 development plan, including:
• Design of the Phase IIb trial;
• Dose selection for the Phase IIb trial; and
• Scope of clinical development required to support a broad indication label.
The FDA’s written response provides a clear development path for MAXY-G34 to achieve a broad label indication for chemotherapy-induced neutropenia. FDA provided feedback on Maxygen’s Phase IIb study proposal, Phase III plan and overall scope of development anticipated to support a Biologic License Application (BLA). This feedback leads Maxygen to conclude that a potential timely and cost effective path to BLA filing for MAXY-G34 in CIN can be achieved.