Mitoxantrone (Page 3 of 11)

Advanced Hormone-Refractory Prostate Cancer

A multicenter Phase 2 trial of mitoxantrone and low-dose prednisone (M + P) was conducted in 27 symptomatic patients with hormone-refractory prostate cancer. Using NPCP (National Prostate Cancer Project) criteria for disease response, there was one partial responder and 12 patients with stable disease. However, nine patients or 33% achieved a palliative response defined on the basis of reduction in analgesic use or pain intensity.

These findings led to the initiation of a randomized multicenter trial (CCI-NOV22) comparing the effectiveness of (M + P) to low-dose prednisone alone (P). Eligible patients were required to have metastatic or locally advanced disease that had progressed on standard hormonal therapy, a castrate serum testosterone level, and at least mild pain at study entry. Mitoxantrone was administered at a dose of 12 mg/m2 by short IV infusion every 3 weeks. Prednisone was administered orally at a dose of 5 mg twice a day. Patients randomized to the prednisone arm were crossed over to the M + P arm if they progressed or if they were not improved after a minimum of 6 weeks of therapy with prednisone alone.

A total of 161 patients were randomized, 80 to the M + P arm and 81 to the P arm. The median mitoxantrone dose administered was 12 mg/m2 per cycle. The median cumulative mitoxantrone dose administered was 73 mg/m2 (range of 12 to 212 mg/m2).

A primary palliative response (defined as a 2-point decrease in pain intensity in a 6-point pain scale, associated with stable analgesic use, and lasting a minimum of 6 weeks) was achieved in 29% of patients randomized to M + P compared to 12% of patients randomized to P alone (p = 0.011). Two responders left the study after meeting primary response criterion for two consecutive cycles. For the purposes of this analysis, these two patients were assigned a response duration of zero days. A secondary palliative response was defined as a 50% or greater decrease in analgesic use, associated with stable pain intensity, and lasting a minimum of 6 weeks. An overall palliative response (defined as primary plus secondary responses) was achieved in 38% of patients randomized to M + P compared to 21% of patients randomized to P (p = 0.025).

The median duration of primary palliative response for patients randomized to M + P was 7.6 months compared to 2.1 months for patients randomized to P alone (p = 0.0009). The median duration of overall palliative response for patients randomized to M + P was 5.6 months compared to 1.9 months for patients randomized to P alone (p = 0.0004).

Time to progression was defined as a 1-point increase in pain intensity, or a > 25% increase in analgesic use, or evidence of disease progression on radiographic studies, or requirement for radiotherapy. The median time to progression for all patients randomized to M + P was 4.4 months compared to 2.3 months for all patients randomized to P alone (p = 0.0001). Median time to death was 11.3 months for all patients on the M + P arm compared to 10.8 months for all patients on P alone (p = 0.2324).

Forty-eight patients on the P arm crossed over to receive M + P. Of these, thirty patients had progressed on P, while 18 had stable disease on P. The median cycle of crossover was 5 cycles (range of 2 to 16 cycles). Time trends for pain intensity prior to crossover were significantly worse for patients who crossed over than for those who remained on P alone (p = 0.012). Nine patients (19%) demonstrated a palliative response on M + P after crossover. The median time to death for patients who crossed over to M + P was 12.7 months.

The clinical significance of a fall in prostate-specific antigen (PSA) concentrations after chemotherapy is unclear. On the CCI-NOV22 trial, a PSA fall of 50% or greater for two consecutive follow-up assessments after baseline was reported in 33% of all patients randomized to the M + P arm and 9% of all patients randomized to the P arm. These findings should be interpreted with caution since PSA responses were not defined prospectively. A number of patients were inevaluable for response, and there was an imbalance between treatment arms in the numbers of evaluable patients. In addition, PSA reduction did not correlate precisely with palliative response, the primary efficacy endpoint of this study. For example, among the 26 evaluable patients randomized to the M + P arm who had a ≥ 50% reduction in PSA, only 13 had a primary palliative response. Also, among 42 evaluable patients on this arm who did not have this reduction in PSA, 8 nonetheless had a primary palliative response.

Investigators at Cancer and Leukemia Group B (CALGB) conducted a Phase 3 comparative trial of mitoxantrone plus hydrocortisone (M + H) versus hydrocortisone alone (H) in patients with hormone-refractory prostate cancer (CALGB 9182). Eligible patients were required to have metastatic disease that had progressed despite at least one hormonal therapy. Progression at study entry was defined on the basis of progressive symptoms, increases in measurable or osseous disease, or rising PSA levels. Mitoxantrone was administered intravenously at a dose of 14 mg/m2 every 21 days and hydrocortisone was administered orally at a daily dose of 40 mg. A total of 242 subjects were randomized, 119 to the M + H arm and 123 to the H arm. There were no differences in survival between the two arms, with a median of 11.1 months in the M + H arm, and 12 months in the H arm (p = 0.3298).

Using NPCP criteria for response, partial responses were achieved in 10 patients (8.4%) randomized to the M + H arm compared with 2 patients (1.6%) randomized to the H arm (p = 0.018). The median time to progression, defined by NPCP criteria, for patients randomized to the M + H arm was 7.3 months compared to 4.1 months for patients randomized to H alone (p = 0.0654).

Approximately 60% of patients on each arm required analgesics at baseline. Analgesic use was measured in this study using a 5-point scale. The best percent change from baseline in mean analgesic use was –17% for 61 patients with available data on the M + H arm, compared with +17% for 61 patients on H alone (p = 0.014). A time trend analysis for analgesic use in individual patients also showed a trend favoring the M + H arm over H alone but was not statistically significant.

Pain intensity was measured using the Symptom Distress Scale (SDS) Pain Item 2 (a 5-point scale). The best percent change from baseline in mean pain intensity was –14% for 37 patients with available data on the M + H arm, compared with +8% for 38 patients on H alone (p = 0.057). A time trend analysis for pain intensity in individual patients showed no difference between treatment arms.

Acute Nonlymphocytic Leukemia

In two large randomized multicenter trials, remission induction therapy for acute nonlymphocytic leukemia (ANLL) with mitoxantrone 12 mg/m2 daily for 3 days as a 10-minute intravenous infusion and cytarabine 100 mg/m2 for 7 days given as a continuous 24-hour infusion was compared with daunorubicin 45 mg/m2 daily by intravenous infusion for 3 days plus the same dose and schedule of cytarabine used with mitoxantrone. Patients who had an incomplete antileukemic response received a second induction course in which mitoxantrone or daunorubicin was administered for 2 days and cytarabine for 5 days using the same daily dosage schedule. Response rates and median survival information for both the U.S. and international multicenter trials are given in Table 3:

Table 3: Response Rates, Time to Response, and Survival in U.S. and International Trials
MITO = mitoxantrone + cytarabineDAUN = daunorubicin + cytarabine
Trial % Complete Response (CR) Median Timesto CR (days) Survival (days)
MITO DAUN MITO DAUN MITO DAUN
U.S. 63 (62/98) 53 (54/102) 35 42 312 237
International 50 (56/112) 51 (62/123) 36 42 192 230

In these studies, two consolidation courses were administered to complete responders on each arm. Consolidation therapy consisted of the same drug and daily dosage used for remission induction, but only 5 days of cytarabine and 2 days of mitoxantrone or daunorubicin were given. The first consolidation course was administered 6 weeks after the start of the final induction course if the patient achieved a complete remission. The second consolidation course was generally administered 4 weeks later. Full hematologic recovery was necessary for patients to receive consolidation therapy. For the U.S. trial, median granulocyte nadirs for patients receiving mitoxantrone + cytarabine for consolidation courses 1 and 2 were 10/mm3 for both courses, and for those patients receiving daunorubicin + cytarabine nadirs were 170/mm3 and 260/mm3 , respectively. Median platelet nadirs for patients who received mitoxantrone + cytarabine for consolidation courses 1 and 2 were 17,000/mm3 and 14,000/mm3 , respectively, and were 33,000/mm3 and 22,000/mm3 in courses 1 and 2 for those patients who received daunorubicin + cytarabine. The benefit of consolidation therapy in ANLL patients who achieve a complete remission remains controversial. However, in the only well-controlled prospective, randomized multicenter trials with mitoxantrone in ANLL, consolidation therapy was given to all patients who achieved a complete remission. During consolidation in the U.S. study, two myelosuppression-related deaths occurred on the mitoxantrone arm and one on the daunorubicin arm. However, in the international study there were eight deaths on the mitoxantrone arm during consolidation which were related to the myelosuppression and none on the daunorubicin arm where less myelosuppression occurred.

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