One complete response was achieved in a patient with anaplastic astrocytoma. This response was seen within 4 weeks and lasted for 6 months, at which time the patient developed recurrence in another part of the brain. Two patients (one case of pontine glioma and one case of metastatic brain tumor) achieved a partial response. In two patients, no change in disease status was reported, while four patients had disease progression. Adverse effects of antineoplaston therapy included itchy skin rash, stiff finger joints, flatulence, and mild myelosuppression.
A multicenter phase II study conducted by the departments of Oncology and Neurology at the Mayo Clinic attempted to assess the pharmacokinetics, toxicity, and efficacy of antineoplastons A10 and AS2-1. Slow patient accrual caused the trial to be closed early. Nine adult patients with anaplastic oligoastrocytoma, anaplastic astrocytoma, or glioblastoma multiforme that had recurred after radiation therapy received escalating doses of A10 and AS2-1, to a target daily dose of 1.0 g/kg for A10 and 0.4 g/kg for AS2-1. Six of the patients experienced a second tumor recurrence, while the remaining three patients experienced their first tumor recurrence.
Of the nine patients enrolled in the trial, six could be evaluated for objective tumor response in accordance with the protocol. At the time of study publication, all patients had died. The median survival time was 5.2 months and the mean survival time was 7.2 months. All patients except one died of tumor progression. The remaining patient died of sepsis related to complications from chemotherapy, which was administered after antineoplaston treatment was discontinued.
None of the six assessable patients showed evidence on computed tomography (CT) scan or magnetic resonance imaging (MRI) of tumor regression associated with antineoplaston treatment; however, all nine patients showed evidence of tumor progression. Antineoplaston treatment was administered for 6 to 66 days, after which treatment was discontinued. Toxicity caused three patients to discontinue treatment and subsequent scans of these patients showed tumor progression. The mean time to treatment failure (progression or unacceptable toxicity) was 29 days.
Burzynski has stated that the results of this study were inconclusive because (1) the duration of treatment was too short and (2) researchers used a dosing regimen known to be ineffective against brain tumors as large as those of the study participants. However, in response, the study authors have stated that all patients in this study received treatment until either tumor progression or unacceptable toxic effects occurred. The National Cancer Institute and the Burzynski Institute agreed to the dosage regimen and study plan before the study was initiated, and the tumor size in seven of the nine patients was within the specified limits.