Temozolomide-induced myelodysplasia

Temozolomide duration and secondary hematological neoplasms: A literature review and implications for patients with neuroendocrine neoplasms

Evidence-based recommendations for the optimal duration and sequencing of temozolomide-based treatments in advanced neuroendocrine neoplasms are lacking. Here, we conducted a systematic review of the literature for a descriptive analysis of temozolomide-associated myelodysplasias and leukemias to guide treatment planning. A database search of PubMed and Embase was conducted to identify case reports and/or case series reporting secondary myelodysplasias or leukemias in the setting of temozolomide therapy. Key data items extracted from the studies were the temozolomide dose and duration, latency to hematological disorder, type of secondary malignancy and cytogenetics. Reported cases were summarized graphically. A total of 16 studies with 27 patient cases of therapy-related hematologic neoplasms were identified, all of which were case reports or case series. The median treatment duration and cumulative dose were 19 months and 18,000 mg/m² , respectively. Most patients (21/27) were diagnosed on, or after, 12 months, while only one patient was diagnosed before 6 months of treatment. Most of the patients were diagnosed, while still on treatment with temozolomide. Graphically, cases clustered around a cumulative dose of 10,000 to 30,000 mg/m² and a latency period of 10 to 40 months which translates to an approximate treatment duration of 12.5 to 37.5 months. Taken together, most reported treatment-related hematological neoplasms appear to develop on or beyond the 12-month mark, while patients are still on treatment with temozolomide. For patients with neuroendocrine neoplasms, where sequencing of multiple therapies is important, we suggest an approach to optimizing treatment duration by establishing disease response at 6 months before continuing further treatment and restricting treatment to or establishing closer vigilance beyond 12 months.

Supramolecular Hydrogel Based Post-Surgical Implant System for Hydrophobic Drug Delivery Against Glioma Recurrence

Purpose

The brain, protected by the cranium externally and the blood–brain barrier (BBB) internally, poses challenges in chemotherapy of aggressive brain tumors. Maximal tumor resection followed by radiation and chemotherapy is the standard treatment protocol; however, a substantial number of patients suffer from recurrence. Systemic circulation of drugs causes myelodysplasia and other side effects. To address these caveats, we report facile synthesis of a polyester-based supramolecular hydrogel as a brain biocompatible implant for in situ delivery of hydrophobic drugs.

Methods

Polycaprolactone-diol (PCL) was linked to polyethyleneglycol-diacid (PEG) via an ester bond. In silico modeling indicated micelle-based aggregation of PCL-PEG co-polymer to form a supramolecular hydrogel. Brain biocompatibility was checked in Sprague Dawley rat brain cortex with MRI, motor function test, and histology. Model hydrophobic drugs carmustine and curcumin entrapment propelled glioma cells into apoptosis-based death evaluated by in vitro cytotoxicity assays and Western blot. In vivo post-surgical xenograft glioma model was developed in NOD-SCID mice and evaluated for efficacy to restrict aggressive regrowth of tumors.

Results

20% (w/v) PCL-PEG forms a soft hydrogel that can cover the uneven and large surface area of a tumor resection cavity and maintain brain density. The PCL-PEG hydrogel was biocompatible, and well-tolerated upon implantation in rat brain cortex, for a study period of 12 weeks. We report for the first time the combination of carmustine and curcumin entrapped as model hydrophobic drugs, increasing their bioavailability and yielding synergistic apoptotic effect on glioma cells. Further in vivo study indicated PCL-PEG hydrogel with a dual cargo of carmustine and curcumin restricted aggressive regrowth post-resection significantly compared with control and animals with intravenous drug treatment.

Conclusion

PCL-PEG soft gel-based implant is malleable compared with rigid wafers used as implants, thus providing larger surface area contact. This stable, biocompatible, supramolecular gel without external crosslinking can find wide applications by interchanging formulation of various hydrophobic drugs to ensure and increase site-specific delivery, avoiding systemic circulation.

Haematological malignancies following temozolomide treatment for paediatric high-grade glioma

BACKGROUND

Temozolomide (TMZ) is widely used in high-grade glioma (HGG). There is a major concern of treatment-induced secondary haematological malignancies (SHMs). Due to the poor overall survival of HGG patients, the true incidence is yet elusive. Thus, the aim of this study was to determine the risk of SHMs following TMZ in paediatric HGG.

METHODS

We analysed 487 patients from the HIT-HGG database of the German-speaking Society of Pediatric Oncology and Hematology with follow up beyond 1 year.

RESULTS

The incidence of SHM was 7.7 ± 3.2% at 10 years. No SHM occurred in 194 patients after first-line TMZ therapy, but four out of 131 patients treated with TMZ for relapse following first-line multiagent chemotherapy experienced SHM (20% at 10 years; p = 0.041). SHMs occurred in two out of 162 patients who underwent multiagent chemotherapy without TMZ (4.1% at 10 years). Gender, patient age and acute haematological toxicity during treatment did not affect the incidence of SHMs.

CONCLUSION

Data of our cohort do not indicate an increased risk of SHM following TMZ treatment when compared to previous chemotherapy regimen. However, if TMZ is administered as a second-line treatment following conventional chemotherapy regimen, the risk might be disproportionately increasing.

A Case of Therapy-Related Acute Myeloid Leukemia Associated with Adjuvant Temozolomide Chemotherapy for Anaplastic Astrocytoma

BACKGROUND

Temozolomide (TMZ) is now standard adjuvant therapy in combination with radiotherapy for patients with newly diagnosed malignant glioma. Treatment-related myelodysplastic syndrome and acute treatment-related leukemia (t-AML) associated with TMZ chemotherapy for patients with glioma is quite a rare complication.

CASE DESCRIPTION

A 43-year-old man with an anaplastic astrocytoma received radiation therapy synchronized with ranimustine and adjuvant TMZ chemotherapy for 15 cycles. Close follow-up magnetic resonance imaging of the head during TMZ chemotherapy showed no evidence of tumor progression. One year after the completion of TMZ chemotherapy, a bone-marrow aspiration was performed because the patient's white blood cell count decreased. He was diagnosed with t-AML based on the bone marrow examination, and then he was referred to the cancer center for the treatment of t-AML.

CONCLUSIONS

In this case study, we continued adjuvant TMZ therapy beyond the recommended 6 cycles. Currently, there is no consensus as to how long the adjuvant TMZ therapy should be continued for the treatment of residual tumor showing no apparent interval change. A new decision-making tool to assess the clinical benefits against the side effects for long-term adjuvant TMZ therapy is needed.

Temozolomide induces the expression of the glioma Big Potassium (gBK) ion channel, while inhibiting fascin-1 expression: possible targets for glioma therapy

OBJECTIVE

Temozolomide (TMZ) improves Glioblastoma Multiforme (GBM) patient survival. The invasive behavior of the glioma cells is the cause of GBM relapse. The glioma BK ion channel (gBK) may provide glioma cells with a mechanism to invade surrounding tissue. gBK contains epitopes that cytolytic T lymphocytes (CTLs) can recognize and kill glioma cells. Fascin-1 is an actin crosslinking molecule that supports microvilli; these membrane protrusions provide a physical defense against CTLs. TMZ was investigated to determine its effect on gBK and fascin-1 expression.

RESEARCH DESIGN AND METHODS

Human glioma cells cultured in TMZ were analyzed for their altered mRNA and gBK protein levels by using quantitative real time PCR, immunostaining and cellular functional assays.

RESULTS

TMZ slowed glioma cell growth and inhibited their transmigratory properties due to loss of fascin-1. TMZ induced increased gBK and HLA expression and allowed these TMZ-treated cells to become better targets for gBK-specific CTLs.

CONCLUSIONS

Besides its traditional chemotherapeutic effect, TMZ can have four other targeted pathways: 1) slowed glioma cell growth; 2) inhibited glioma cell transmigration; 3) increased HLA-A2 and gBK tumor antigen production; 4) increased CTL-mediated cytolysis of the TMZ treated glioma cells due to the loss of their defensive membrane protrusions supported by fascin-1.

Temozolomide-related hematologic toxicity

Temozolomide (TMZ) is an oral alkylating agent used for the treatment of recurrent or newly diagnosed malignant gliomas with significant survival benefit. TMZ is generally well tolerated and safe. The most common side effects are mild to moderate, and are represented by fatigue, nausea, vomiting, thrombocytopenia, and neutropenia. However severe hematologic adverse events (HAEs), including myelodysplastic syndrome and aplastic anemia, have also been reported. In this review we present an overview of the available literature of HAEs after exposure to TMZ.

Temozolomide-related idiosyncratic and other uncommon toxicities: a systematic review

Temozolomide (TMZ)-related idiosyncratic and other uncommon toxicities have been reported. To better characterize these toxicities and to identify any associated risk factors, we performed a systematic review. We searched the PubMed database, limited to the English language, published between 1999 and December 2011. We selected only those articles in which TMZ was temporally related and was the sole or main contributing chemotherapeutic drug to idiosyncratic drug reactions (IDRs) and other uncommon toxicities. Hematological IDRs are biopsy-proven aplastic anemia or grade V toxicity or grade IV toxicity with slow and incomplete hematological recovery. Seventy-three cases were identified, including 21 hematological IDRs, 31 nonhematological IDRs and uncommon infections, and 21 second primary cancers. With a caveat of publication and reporting bias, the following observations could be made. The hematological IDRs predominantly occurred in female patients (exact binomial two-tailed, P=0.0041) and most patients were receiving TMZ concomitantly with radiotherapy for glioma. The median duration of exposure to TMZ was 30 days and the median cumulative TMZ exposure was 2250 mg/m (range, 500-6900 mg/m). The sex predilection was not evident in nonhematological IDRs and other uncommon toxicities. TMZ-induced pneumonitis and cholestatic hepatitis are emerging as a nonhematological hypersensitive reaction and IDR, respectively. For TMZ-related myelodysplasia or leukemia, the cumulative dose of TMZ ranged from 1400 to 30 000 mg/m. The cumulative dose of TMZ was lower and latency was shorter with a previous exposure to other leukemogenic drugs, suggesting that TMZ may have augmented the leukemogenic potential of other drugs. Early appearance of profound myelosuppression during the course of TMZ and concurrent radiotherapy could be a hematological IDR, which warrants prompt investigations to exclude aplastic anemia. Myelodysplasia or leukemia developed after a median TMZ exposure of 15 g/m.

Extreme thrombocytosis and cardiovascular surgery: risks and management

Extreme thrombocytosis is a major risk factor for excessive bleeding and for thrombosis, either of which can complicate cardiovascular surgical and interventional procedures. Extreme thrombocytosis can also cause an unusual syndrome, erythromelalgia, that results in a type of chronic microvascular occlusive arterial disease. We present the differential diagnosis of conditions that may lead to extreme thrombocytosis, 3 cases (each of which illustrates a different potential complication), and a review of the pertinent medical literature. Correcting excessive thrombocytosis is typically not difficult, whether electively or acutely, and effective therapy usually controls thrombosis and excessive hemorrhage post-procedurally.

Temozolomide for corticotroph pituitary adenomas refractory to standard therapy

To highlight the potential of temozolomide (TMZ) to induce rapid tumor regression in patients with aggressive corticotroph adenomas (CA) that are refractory to surgery and radiation therapy and to review use of TMZ in other pituitary tumors. We present a case of a 56-year-old male with a 3 cm CA treated with transphenoidal surgery (TSS) and conventional radiotherapy in the same year. His hypercortisolemia recurred 11 years later with rapid tumor growth (to 4.2 × 2.5 cm) and he underwent a second TSS with good resection. The tumor recurred 6 months later with ophthalmoplegia. Over 16 months he underwent an additional three surgeries (two TSS, one craniotomy) and repeated conventional radiotherapy. Ki67 staining index on surgical specimens was 5-6%. Temozolomide is an oral alkylating agent approved for glioblastoma multiforme treatment that has only recently shown promise in treating some pituitary tumors. In this patient TMZ was started at 150 mg/m²/day, titrated to 200 mg/m²/day, taken 5 days per month. The only significant side effect was moderate nausea. After 10 weeks, the tumor showed a remarkable 60% regression with objective improvement in ophthalmoplegia. Treatment of aggressive CAs represents a therapeutic challenge and in some cases surgical debulking and radiotherapy are of limited success. Few reports of CAs responsive to TMZ have been reported in the literature. To our knowledge, this case represents the most rapid robust CA shrinkage response reported to date. Further randomized clinical trials of TMZ in the treatment of aggressive pituitary adenomas are warranted.