Mechanism of Action
Mitoxantrone, a DNA-reactive agent that intercalates into deoxyribonucleic acid (DNA) through hydrogen bonding, causes crosslinks and strand breaks. Mitoxantrone also interferes with ribonucleic acid (RNA) and is a potent inhibitor of topoisomerase II, an enzyme responsible for uncoiling and repairing damaged DNA. It has a cytocidal effect on both proliferating and nonproliferating cultured human cells, suggesting lack of cell cycle phase specificity.
Mitoxantrone injection (concentrate) has been shown in vitro to inhibit B cell, T cell, and macrophage proliferation and impair antigen presentation, as well as the secretion of interferon gamma, TNFα, and IL-2.
Pharmacokinetics
Pharmacokinetics of mitoxantrone in patients following a single intravenous administration of mitoxantrone injection (concentrate) can be characterized by a three-compartment model. The mean alpha half-life of mitoxantrone is 6 to 12 minutes, the mean beta half-life is 1.1 to 3.1 hours and the mean gamma (terminal or elimination) half-life is 23 to 215 hours (median approximately 75 hours). Pharmacokinetic studies have not been performed in humans receiving multiple daily dosing. Distribution to tissues is extensive: steady-state volume of distribution exceeds 1,000 L/m2. Tissue concentrations of mitoxantrone appear to exceed those in the blood during the terminal elimination phase. In the healthy monkey, distribution to brain, spinal cord, eye, and spinal fluid is low.
In patients administered 15 to 90 mg/m2 of mitoxantrone intravenously, there is a linear relationship between dose and the area under the concentration-time curve (AUC).
Mitoxantrone is 78% bound to plasma proteins in the observed concentration range of 26 to 455 ng/mL. This binding is independent of concentration and is not affected by the presence of phenytoin, doxorubicin, methotrexate, prednisone, prednisolone, heparin, or aspirin.
Metabolism and Elimination
Mitoxantrone is excreted in urine and feces as either unchanged drug or as inactive metabolites. In human studies, 11% and 25% of the dose were recovered in urine and feces, respectively, as either parent drug or metabolite during the 5-day period following drug administration. Of the material recovered in urine, 65% was unchanged drug. The remaining 35% was composed of monocarboxylic and dicarboxylic acid derivatives and their glucuronide conjugates. The pathways leading to the metabolism of mitoxantrone have not been elucidated.
Special Populations
GenderThe effect of gender on mitoxantrone pharmacokinetics is unknown.
GeriatricIn elderly patients with breast cancer, the systemic mitoxantrone clearance was 21.3 L/hr/m2, compared with 28.3 L/hr/m2 and 16.2 L/hr/m2 for non-elderly patients with nasopharyngeal carcinoma and malignant lymphoma, respectively.
PediatricMitoxantrone pharmacokinetics in the pediatric population are unknown.
RaceThe effect of race on mitoxantrone pharmacokinetics is unknown.
Renal ImpairmentMitoxantrone pharmacokinetics in patients with renal impairment are unknown.
Hepatic ImpairmentMitoxantrone clearance is reduced by hepatic impairment. Patients with severe hepatic dysfunction (bilirubin > 3.4 mg/dL) have an AUC more than three times greater than that of patients with normal hepatic function receiving the same dose. Patients with multiple sclerosis who have hepatic impairment should ordinarily not be treated with mitoxantrone. Other patients with hepatic impairment should be treated with caution and dosage adjustment may be required.
Drug Interactions
In vitro drug interaction studies have demonstrated that mitoxantrone did not inhibit CYP450 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4 across a broad concentration range. The results of in vitro induction studies are inconclusive, but suggest that mitoxantrone may be a weak inducer of CYP450 2E1 activity.
Pharmacokinetic studies of the interaction of mitoxantrone with concomitantly administered medications in humans have not been performed. The pathways leading to the metabolism of mitoxantrone have not been elucidated. To date, post-marketing experience has not revealed any significant drug interactions in patients who have received mitoxantrone for treatment of cancer. Information on drug interactions in patients with multiple sclerosis is limited.
Clinical Trials
Multiple Sclerosis
The safety and efficacy of mitoxantrone in multiple sclerosis were assessed in two randomized, multicenter clinical studies.
One randomized, controlled study (Study 1) was conducted in patients with secondary progressive or progressive relapsing multiple sclerosis. Patients in this study demonstrated significant neurological disability based on the Kurtzke Expanded Disability Status Scale (EDSS). The EDSS is an ordinal scale with 0.5 point increments ranging from 0 to 10 (increasing score indicates worsening) and based largely on ambulatory impairment in its middle range (EDSS 4.5 to 7.5 points). Patients in this study had experienced a mean deterioration in EDSS of about 1.6 points over the 18 months prior to enrollment.
Patients were randomized to receive placebo, 5 mg/m2 mitoxantrone, or 12 mg/m2 mitoxantrone administered IV every 3 months for 2 years. High-dose methylprednisolone was administered to treat relapses. The intent-to-treat analysis cohort consisted of 188 patients; 149 completed the 2-year study. Patients were evaluated every 3 months, and clinical outcome was determined after 24 months. In addition, a subset of patients was assessed with magnetic resonance imaging (MRI) at baseline, Month 12, and Month 24. Neurologic assessments and MRI reviews were performed by evaluators blinded to study drug and clinical outcome, although the diagnosis of relapse and the decision to treat relapses with steroids were made by unblinded treating physicians. A multivariate analysis of five clinical variables (EDSS, Ambulation Index [AI], number of relapses requiring treatment with steroids, months to first relapse needing treatment with steroids, and Standard Neurological Status [SNS]) was used to determine primary efficacy. The AI is an ordinal scale ranging from 0 to 9 in one point increments to define progressive ambulatory impairment. The SNS provides an overall measure of neurologic impairment and disability, with scores ranging from 0 (normal neurologic examination) to 99 (worst possible score).
Results of Study 1 are summarized in Table 1.
Table 1: Efficacy Results at Month 24 Study 1
|
Treatment Groups |
p-value |
|
|
Mitoxantrone |
|
Primary Endpoints |
Placebo
(N = 64) |
5 mg/m2
(N = 64) |
12 mg/m2
(N = 60) |
Placebo vs. 12 mg/m2 Mitoxantrone |
| NR = not reached within 24 months; MRI = magnetic resonance imaging. |
|
| Primary efficacy multivariate analysis |
- |
- |
- |
< 0.0001 |
| Primary clinical variables analyzed: |
|
|
|
|
| EDSS change (mean) |
0.23 |
-0.23 |
-0.13 |
0.0194 |
| Ambulation Index change† (mean) |
0.77 |
0.41 |
0.30 |
0.0306 |
| Mean number of relapses per patient requiring corticosteroid treatment (adjusted for discontinuation) |
1.20 |
0.73 |
0.40 |
0.0002 |
| Months to first relapse requiring corticosteroid treatment (median [1st quartile]) |
14.2 [6.7] |
NR [6.9] |
NR [20.4] |
0.0004 |
| Standard Neurological Status change† (mean) |
0.77 |
-0.38 |
-1.07 |
0.0269 |
| MRI |
|
|
|
|
| No. of patients with new GD-enhancing lesions |
5/32 (16%) |
4/37 (11%) |
0/31 |
0.022 |
| Change in number of T2-weighted lesions, mean (n) |
1.94 (32) |
0.68 (34) |
0.29 (28) |
0.027 |
A second randomized, controlled study (Study 2) evaluated mitoxantrone in combination with methylprednisolone (MP) and was conducted in patients with secondary progressive or worsening relapsing-remitting multiple sclerosis who had residual neurological deficit between relapses. All patients had experienced at least two relapses with sequelae or neurological deterioration within the previous 12 months. The average deterioration in EDSS was 2.2 points during the previous 12 months. During the screening period, patients were treated with two monthly doses of 1 g of IV MP and underwent monthly MRI scans. Only patients who developed at least one new Gd-enhancing MRI lesion during the 2-month screening period were eligible for randomization. A total of 42 evaluable patients received monthly treatments of 1 g of IV MP alone (n = 21) or ~12 mg/m2 of IV mitoxantrone plus 1 g of IV MP (n = 21) (MIT + MP) for 6 months. Patients were evaluated monthly, and study outcome was determined after 6 months. The primary measure of effectiveness in this study was a comparison of the proportion of patients in each treatment group who developed no new Gd-enhancing MRI lesions at 6 months; these MRIs were assessed by a blinded panel. Additional outcomes were measured, including EDSS and number of relapses, but all clinical measures in this trial were assessed by an unblinded treating physician. Five patients, all in the MP alone arm, failed to complete the study due to lack of efficacy.
The results of this trial are displayed in Table 2.
Table 2: Efficacy Results Study 2
| Primary Endpoint |
MP alone
(N = 21) |
MIT + MP
(N = 21) |
p-value |
| MP = Methylprednisolone; MIT + MP = Mitoxantrone plus Methylprednisolone. |
|
| Patients (%) without new Gd-enhancing lesions on MRIs (primary endpoint) |
5 (31%) |
19 (90%) |
0.001 |
| Secondary Endpoints |
|
|
|
| EDSS change (Month 6 minus baseline)* (mean) |
-0.1 |
-1.1 |
0.013 |
| Annualized relapse rate (mean per patient) |
3 |
0.7 |
0.003 |
| Patients (%) without relapses |
7 (33%) |
14 (67%) |
0.031 |
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
Trial |
% Complete
Response (CR) |
Median Time
to CR (days) |
Survival (days) |
MIT = Mitoxantrone Injection USP (concentrate) + Cytarabine
DAUN = Daunorubicin + Cytarabine |
|
MIT |
DAUN |
MIT |
DAUN |
MIT |
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.
Indications and Usage for Mitoxantrone Injection Concentrate
Mitoxantrone injection USP (concentrate) is indicated for reducing neurologic disability and/or the frequency of clinical relapses in patients with secondary (chronic) progressive, progressive relapsing, or worsening relapsing-remitting multiple sclerosis (i.e., patients whose neurologic status is significantly abnormal between relapses). Mitoxantrone injection USP (concentrare) is not indicated in the treatment of patients with primary progressive multiple sclerosis.
The clinical patterns of multiple sclerosis in the studies were characterized as follows: secondary progressive and progressive relapsing disease were characterized by gradual increasing disability with or without superimposed clinical relapses, and worsening relapsing-remitting disease was characterized by clinical relapses resulting in a step-wise worsening of disability.
Mitoxantrone injection USP (concentrate) in combination with corticosteroids is indicated as initial chemotherapy for the treatment of patients with pain related to advanced hormone-refractory prostate cancer.
Mitoxantrone injection USP (concentrate) in combination with other approved drug(s) is indicated in the initial therapy of acute nonlymphocytic leukemia (ANLL) in adults. This category includes myelogenous, promyelocytic, monocytic, and erythroid acute leukemias.
Contraindications
Mitoxantrone is contraindicated in patients who have demonstrated prior hypersensitivity to it.
Warnings
WHEN MITOXANTRONE IS USED IN HIGH DOSES (> 14 mg/m2/d × 3 days) SUCH AS INDICATED FOR THE TREATMENT OF LEUKEMIA, SEVERE MYELOSUPPRESSION WILL OCCUR. THEREFORE, IT IS RECOMMENDED THAT MITOXANTRONE BE ADMINISTERED ONLY BY PHYSICIANS EXPERIENCED IN THE CHEMOTHERAPY OF THIS DISEASE. LABORATORY AND SUPPORTIVE SERVICES MUST BE AVAILABLE FOR HEMATOLOGIC AND CHEMISTRY MONITORING AND ADJUNCTIVE THERAPIES, INCLUDING ANTIBIOTICS. BLOOD AND BLOOD PRODUCTS MUST BE AVAILABLE TO SUPPORT PATIENTS DURING THE EXPECTED PERIOD OF MEDULLARY HYPOPLASIA AND SEVERE MYELOSUPPRESSION. PARTICULAR CARE SHOULD BE GIVEN TO ASSURING FULL HEMATOLOGIC RECOVERY BEFORE UNDERTAKING CONSOLIDATION THERAPY (IF THIS TREATMENT IS USED) AND PATIENTS SHOULD BE MONITORED CLOSELY DURING THIS PHASE. MITOXANTRONE ADMINISTERED AT ANY DOSE CAN CAUSE MYELOSUPPRESSION.
General
Patients with preexisting myelosuppression as the result of prior drug therapy should not receive mitoxantrone unless it is felt that the possible benefit from such treatment warrants the risk of further medullary suppression.
The safety of mitoxantrone injection (concentrate) in patients with hepatic insufficiency is not established (see CLINICAL PHARMACOLOGY).
Safety for use by routes other than intravenous administration has not been established.
Mitoxantrone is not indicated for subcutaneous, intramuscular, or intra-arterial injection. There have been reports of local/regional neuropathy, some irreversible, following intra-arterial injection.
Mitoxantrone must not be given by intrathecal injection. There have been reports of neuropathy and neurotoxicity, both central and peripheral, following intrathecal injection. These reports have included seizures leading to coma and severe neurologic sequelae, and paralysis with bowel and bladder dysfunction.
Topoisomerase II inhibitors, including mitoxantrone, have been associated with the development of secondary acute myeloid leukemia and myelosuppression.
Cardiac Effects
Because of the possible danger of cardiac effects in patients previously treated with daunorubicin or doxorubicin, the benefit-to-risk ratio of mitoxantrone therapy in such patients should be determined before starting therapy.
Functional cardiac changes including decreases in left ventricular ejection fraction (LVEF) and irreversible congestive heart failure can occur with mitoxantrone. Cardiac toxicity may be more common in patients with prior treatment with anthracyclines, prior mediastinal radiotherapy, or with preexisting cardiovascular disease. Such patients should have regular cardiac monitoring of LVEF from the initiation of therapy. Cancer patients who received cumulative doses of 140 mg/m2 either alone or in combination with other chemotherapeutic agents had a cumulative 2.6% probability of clinical congestive heart failure. In comparative oncology trials, the overall cumulative probability rate of moderate or severe decreases in LVEF at this dose was 13%.
Multiple SclerosisChanges in cardiac function may occur in patients with multiple sclerosis treated with mitoxantrone. In one controlled trial (Study 1, see CLINICAL TRIALS, Multiple Sclerosis ), two patients (2%) of 127 receiving mitoxantrone, one receiving a 5 mg/m2 dose and the other receiving the 12 mg/m2 dose, had LVEF values that decreased to below 50%. An additional patient receiving 12 mg/m2, who did not have LVEF measured, had a decrease in another echocardiographic measurement of ventricular function (fractional shortening) that led to discontinuation from the trial (see ADVERSE REACTIONS, Multiple Sclerosis). There were no reports of congestive heart failure in either controlled trial.
MS patients should be assessed for cardiac signs and symptoms by history, physical examination, ECG, and quantitative LVEF evaluation using appropriate methodology (ex. Echocardiogram, MUGA, MRI, etc.) prior to the start of mitoxantrone therapy. MS patients with a baseline LVEF below the lower limit of normal should not be treated with mitoxantrone. Subsequent LVEF and ECG evaluations are recommended if signs or symptoms of congestive heart failure develop and prior to every dose administered to MS patients. Mitoxantrone should not be administered to MS patients who experience a reduction in LVEF to below the lower limit of normal, to those who experience a clinically significant reduction in LVEF, or to those who have received a cumulative lifetime dose of 140 mg/m2. MS patients should have yearly quantitative LVEF evaluation after stopping mitoxantrone to monitor for late-occurring cardiotoxicity.
LeukemiaAcute congestive heart failure may occasionally occur in patients treated with mitoxantrone for ANLL. In first-line comparative trials of mitoxantrone + cytarabine vs. daunorubicin + cytarabine in adult patients with previously untreated ANLL, therapy was associated with congestive heart failure in 6.5% of patients on each arm. A causal relationship between drug therapy and cardiac effects is difficult to establish in this setting since myocardial function is frequently depressed by the anemia, fever and infection, and hemorrhage that often accompany the underlying disease.
Hormone-Refractory Prostate CancerFunctional cardiac changes such as decreases in LVEF and congestive heart failure may occur in patients with hormone-refractory prostate cancer treated with mitoxantrone. In a randomized comparative trial of mitoxantrone plus low-dose prednisone vs. low-dose prednisone, 7 of 128 patients (5.5 %) treated with mitoxantrone had a cardiac event defined as any decrease in LVEF below the normal range, congestive heart failure (n = 3), or myocardial ischemia. Two patients had a prior history of cardiac disease. The total mitoxantrone dose administered to patients with cardiac effects ranged from > 48 to 212 mg/m2.
Among 112 patients evaluable for safety on the mitoxantrone + hydrocortisone arm of the CALGB trial, 18 patients (19%) had a reduction in cardiac function, 5 patients (5%) had cardiac ischemia, and 2 patients (2%) experienced pulmonary edema. The range of total mitoxantrone doses administered to these patients is not available.
Pregnancy
Mitoxantrone may cause fetal harm when administered to a pregnant woman. Women of childbearing potential should be advised to avoid becoming pregnant. Mitoxantrone is considered a potential human teratogen because of its mechanism of action and the developmental effects demonstrated by related agents. Treatment of pregnant rats during the organogenesis period of gestation was associated with fetal growth retardation at doses ≥ 0.1 mg/kg/day (0.01 times the recommended human dose on a mg/m2 basis). When pregnant rabbits were treated during organogenesis, an increased incidence of premature delivery was observed at doses ≥ 0.1 mg/kg/day (0.01 times the recommended human dose on a mg/m2 basis). No teratogenic effects were observed in these studies, but the maximum doses tested were well below the recommended human dose (0.02 and 0.05 times in rats and rabbits, respectively, on a mg/m2 basis). There are no adequate and well-controlled studies in pregnant women. Women with multiple sclerosis who are biologically capable of becoming pregnant should have a pregnancy test prior to each dose, and the results should be known prior to administration of the drug. If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential risk to the fetus.
Secondary Leukemia
Mitoxantrone injection (concentrate) therapy increases the risk of developing secondary leukemia in patients with cancer and in patients with multiple sclerosis.
In a study of patients with prostate cancer, acute myeloid leukemia occurred in 1% (5/487) of mitoxantrone-treated patients versus no cases in the control group (0/496) not receiving mitoxantrone at 4.7 years follow-up.
In a prospective, open-label, tolerability and safety monitoring study of mitoxantrone treated MS patients followed for up to five years (median of 2.8 years), leukemia occurred in 0.6% (3/509) of patients. Publications describe leukemia risks of 0.25% to 2.8% in cohorts of patients with MS treated with mitoxantrone and followed for varying periods of time. This leukemia risk exceeds the risk of leukemia in the general population. The most commonly reported types were acute promyelocytic leukemia and acute myelocytic leukemia.
In 1774 patients with breast cancer who received mitoxantrone concomitantly with other cytotoxic agents and radiotherapy, the cumulative risk of developing treatment-related acute myeloid leukemia was estimated as 1.1% and 1.6% at 5 and 10 years, respectively. The second largest report involved 449 patients with breast cancer treated with mitoxantrone, usually in combination with radiotherapy and/or other cytotoxic agents. In this study, the cumulative probability of developing secondary leukemia was estimated to be 2.2% at 4 years.
Secondary acute myeloid leukemia has also been reported in cancer patients treated with anthracyclines. Mitoxantrone is an anthracenedione, a related drug. The occurrence of secondary leukemia is more common when anthracyclines are given in combination with DNA-damaging antineoplastic agents, when patients have been heavily pretreated with cytotoxic drugs, or when doses of anthracyclines have been escalated.
Symptoms of acute leukemia may include excessive bruising, bleeding, and recurrent infections.
Precautions
General
Therapy with mitoxantrone should be accompanied by close and frequent monitoring of hematologic and chemical laboratory parameters, as well as frequent patient observation.
Systemic infections should be treated concomitantly with or just prior to commencing therapy with mitoxantrone.
Information for Patients
Mitoxantrone may impart a blue-green color to the urine for 24 hours after administration, and patients should be advised to expect this during therapy. Bluish discoloration of the sclera may also occur. Patients should be advised of the signs and symptoms of myelosuppression.
Patients with multiple sclerosis should be provided with the Patient Package Insert at the time that the decision is made to treat with mitoxantrone and prior to and in close temporal proximity to each treatment. In addition, the physician should discuss the issues addressed in the Patient Package Insert with the patient.
Laboratory Tests
A complete blood count, including platelets, should be obtained prior to each course of mitoxantrone and in the event that signs and symptoms of infection develop. Liver function tests should also be performed prior to each course of therapy. Mitoxantrone therapy in multiple sclerosis patients with abnormal liver function tests is not recommended because mitoxantrone clearance is reduced by hepatic impairment and no laboratory measurement can predict drug clearance and dose adjustments.
In leukemia treatment, hyperuricemia may occur as a result of rapid lysis of tumor cells by mitoxantrone. Serum uric acid levels should be monitored and hypouricemic therapy instituted prior to the initiation of antileukemic therapy.
Women with multiple sclerosis who are biologically capable of becoming pregnant, even if they are using birth control, should have a pregnancy test, and the results should be known, before receiving each dose of mitoxantrone (see WARNINGS, Pregnancy).
Carcinogenesis, Mutagenesis, Impair
