Activity of topotecan in retinoblastoma

Intravitreal Topotecan for Vitreous Seeds in Retinoblastoma: A Long-term Review of 91 Eyes

PURPOSE

To study the long-term efficacy of intravitreal topotecan (IVT) for vitreous seeds in eyes with retinoblastoma and risk factors for their recurrence.

DESIGN

Retrospective, non-comparative, interventional study.

PARTICIPANTS

Ninety-one eyes of 90 patients with retinoblastoma treated between January 2013 and April 2019.

METHODS

Patients with recurrent or refractory vitreous seeds after completion of intravenous or intra-arterial chemotherapy were treated with IVT (30 μg/0.15 ml) by the safety-enhanced technique. The injection was repeated every 4 weeks until the regression of seeds. Patients with a minimum follow-up of 12 months were included in the analysis.

MAIN OUTCOME MEASURES

Primary outcome measures were vitreous seed regression and eye salvage. Secondary outcomes were risk factors for vitreous seed recurrence after treatment with IVT, vision salvage, and complications of IVT.

RESULTS

The median age of the patients was 18 months, with most having group D (n = 58 [64%]) and group E (n = 26 [29%]) retinoblastoma. Vitreous seeds were refractory in 46 eyes (51%) and recurrent in 45 eyes (49%). A total of 317 IVT injections were administered, with the median being 3 injections. The median number of IVT injections required was 2.5 injections for dust, 3 injections for sphere, and 5 injections for cloud morphologic features. Recurrence of vitreous seeds after IVT was seen in 17 eyes (19%) at a mean follow-up of 7.9 months. At a mean follow-up 34 months, vitreous seed regression was achieved in 88 eyes (97%) and eye salvage was achieved in 77 eyes (85%). Older age (P = 0.018) and recurrence of retinal tumor (15/17 eyes; P < 0.01) significantly increased the risk of vitreous seed recurrence. Cataract was the most common complication seen in 17 eyes (9%).

CONCLUSIONS

Intravitreal topotecan at an every 3- to 4-week regimen is effective against both refractory and recurrent vitreous seeds. The vitreous seed morphologic features correspond to the number of injections required for regression. Increasing age and recurrence of retinal tumor increase the risk of vitreous seed recurrence after treatment with IVT.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

SECONDARY SALVAGE INTRAVENOUS CHEMOTHERAPY FOR REFRACTORY/RECURRENT RETINOBLASTOMA: A Study of 41 Eyes

PURPOSE

To determine the efficacy of secondary salvage intravenous chemotherapy (IVC) for refractory/recurrent retinoblastoma.

METHODS

Retrospective, nonrandomized interventional case series of 41 eyes of 33 patients with recurrent retinoblastoma.

RESULTS

Of the 33 patients, mean age at the time of commencement of salvage IVC was 5 years (median, 5 years; range, 2-8 years). At presentation, recurrent retinoblastoma in 41 eyes of 33 patients was classified by the International Classification of Retinoblastoma as Group B (n = 7; 17%), Group C (n = 3; 7%), Group D (n = 16; 39%), and Group E (n = 15; 37%). All patients received 6 cycles of IVC as primary treatment. The indication for secondary salvage IVC with focal treatment included recurrent solid tumor (n = 36; 88%), subretinal seeds (n = 22; 54%), or persistent solid tumor (n = 2; 5%). Mean number of cycles of salvage IVC were 8 (median, 6; range, 6-18). Over a mean follow-up period of 43 months (median, 43 months; range, 12-96 months) after completion of salvage IVC, globe salvage was achieved in 22 (54%) eyes, 1 (3%) patient had histopathology-proven bone metastasis, and 1 (3%) patient died because of presumed metastasis.

CONCLUSION

Secondary salvage IVC with appropriate focal treatment allows globe salvage in 54% eyes with refractory/recurrent retinoblastoma and thus serves as an alternative to intraarterial chemotherapy or enucleation.

Efficacy of topotecan nanoparticles for intravitreal chemotherapy of retinoblastoma

Retinoblastoma (Rb) is the most common intraocular malignancy in children that accounts for approximately 4% of all pediatric malignancies. Since chemotherapy is a widely practiced treatment for Rb, there is a growing interest in developing new and effective drugs to overcome systemic and local side effects of chemotherapy to improve the quality of life and increase the chances of survival. This study sought to fabricate thiolated chitosan nanoparticles containing topotecan (TPH-TCs-NPs) with a view of enhancing drug loading and release control. This research was also designed to assess the ability of TPH-TCs-NPs to improve cell association, increase treatment efficacy in retinoblastoma cells and xenograft-rat-model of retinoblastoma, and overcome current topotecan hydrochloride (TPH) intravitreal administration challenges, including stability loss and poor cellular uptake. Modified ionic gelation method was optimized to fabricate TPH-TCs-NPs and TPH-TMC-NPs (N-trimethyl chitosan nanoparticles containing TPH). We characterized the NPs and quantified topotecan loading and release against a free TPH standard. The efficacy of TPH-NPs was quantified in human retinoblastoma cells (Y79) by XTT and flow cytometry measurement. In addition, Y79 cells were injected intravitreally in both eyes of immunodeficient wistar albino rats to create a xenograft-rat-model to compare the antitumor effectiveness of TPH-NPs and TPH by intravitreal administration. TPH-NPs complexation was confirmed by EDX, FTIR, and DSC techniques. TPH-TCs-NPs and TPH-TMC-NPs had high encapsulation efficiency (85.23 ± 2 and 73.34 ± 2% respectively). TPH-TCs-NPs showed a mean diameter, polidispersity index, and zeta potential of 25±2 nm, 0.21 ± 0.03 and +12 ± 2 mV, respectively. As a function of dose, TCs and TMC NPs were more efficacious than free topotecan (IC50s 53.17 and 85.88 nM, relative to 138.30 nM respectively, P = 0.012). Kruskal-Wallis test showed a statistically significant difference between the groups. Additionally, a significant difference between the tumor control and TPH-TCs-NPs treated group in xenograft-rat-model ( Range of P-value: 0.026 to 0.035) was shown by Bonferroni post hoc test. The current investigation demonstrated enhanced efficacy and association of TPH-TCs-NPs relative to free TPH in retinoblastoma cells and tumor in vitro and in vivo.

Management and Outcomes of Unilateral Group D Tumors in Retinoblastoma

Purpose

Retinoblastoma presents most commonly as advanced unilateral disease, particularly in developing countries for which primary enucleation has been the preferred method of treatment. However, with the evolution of newer treatment modalities including intravitreal chemotherapy, intra-arterial chemotherapy and newer chemotherapeutic combinations, a trend towards more conservative approaches is being observed. Our aim is to evaluate outcomes of group D eyes following conservative and non-conservative treatment options.

Patients and Methods

The ocular oncology database was used to identify eyes with unilateral retinoblastoma that fulfilled the International Intraocular Retinoblastoma Classification (IIRC) group D criteria from August 2010 to August 2018 and these were retrospectively reviewed. Overall, 39 eyes were identified.

Results

Nineteen (49%) eyes underwent primary enucleation and 20 (51%) received eye-conserving treatment. Eye salvage was possible in 15 (75%) eyes in the attempted salvage group. None of the patient revealed signs of metastasis. All eyes received conventional chemotherapy (carboplatin, vincristine, etoposide) and focal laser therapy. Additional treatment modalities offered included intravitreal chemotherapy, intra-arterial chemotherapy and topotecan. Three (11%) eyes in the primary enucleation group showed high-risk features on histopathology and none developed metastasis.

Conclusion

The results of the study seem promising and conservative measures can be adopted in selected unilateral group D eyes.

Periocular topotecan for vitreous seeds in retinoblastoma

Purpose:

Refractory or recurrent vitreous seeds account for a large proportion of failure of eye salvage in retinoblastoma. The purpose of this study is to evaluate the efficacy of periocular topotecan (POT) in the management of vitreous seeds in retinoblastoma.

Methods:

Retrospective, interventional study of patients with retinoblastoma with vitreous seeds who received POT concurrent with intravenous chemotherapy (IVC).

Results:

Thirty-eight eyes of 35 patients received POT. Five eyes (13%) belonged to International Classification of Retinoblastoma group C, 23 eyes (61%) belonged to group D, and 10 eyes (26%) belonged to group E. Primary treatment included IVC with a combination of carboplatin, etoposide, and vincristine for a mean of 6 cycles (median 6; range 6–9). Concurrent to IVC from the fourth cycle onward, all patients received POT. Focal vitreous seeds were present in 20 eyes (53%) which received a mean of 3 injections (median 3; range 1–7). Diffuse vitreous seeds were present in 18 eyes (47%) which received a mean of 4 injections (median 5; range 1–7). At a mean follow-up of 8.5 months (median 5 months; range 1–15 months), regression of focal and diffuse vitreous seeds was achieved in 16 eyes (80%) and 8 eyes (44%), respectively. In all, 24 eyes (63%) had complete remission of vitreous seeds with POT given concurrently with IVC. Eye salvage was possible in 19 eyes (95%) with focal vitreous seeds and 12 eyes (68%) with diffuse VS. Enucleation was necessary for persistent vitreous seeds and viable tumor in five eyes (13%), viable tumor alone in one eye (0.02%), and recurrent vitreous seeds in one eye (0.02%). None of the patients developed systemic metastasis.

Conclusion:

POT administered concurrent with IVC is safe and effective in the initial management of vitreous seeds.

Intravitreal topotecan in the management of refractory and recurrent vitreous seeds in retinoblastoma

BACKGROUND/AIM

To evaluate the efficacy of intravitreal topotecan for refractory or recurrent vitreous seeds in retinoblastoma.

METHODS

Intravitreal injection of topotecan hydrochloride (30 µg/0.15 mL) was provided every 3 weeks by the safety enhanced technique.

RESULTS

The study included 17 consecutive patients with retinoblastoma with refractory or recurrent vitreous seeds. Five eyes (29%) belonged to International Classification of Retinoblastoma group C and 12 eyes (71%) belonged to group D. Primary treatment included triple drug intravenous chemotherapy for a mean of 10 cycles (median, 9 cycles; range, 6-18 cycles). Fifteen patients (88%) had undergone 56 periocular carboplatin injections with a mean of 4 injections (median, 3 injections; range, 1-8 injections), concurrent with intravenous chemotherapy. A total of 53 intravitreal topotecan injections were performed in 17 eyes of 17 consecutive patients with refractory or recurrent vitreous seeds with a mean of 3 injections (median, 3 injections; range, 2-6 injections). Complete regression of vitreous seeds was achieved in 17 of 17 eyes (100%). At a mean follow-up of 23.8 months (median, 24 months; range, 15.1-34.1 months), one eye (6%) with a recurrent retinal tumour needed enucleation, and the rest of the 16 eyes (94%) maintained complete regression. Final visual acuity could be reliably assessed in all 16 eyes (100%), of whom 12 eyes (75%) had visual acuity ≥20/200. None of the patients developed ocular or systemic complications.

CONCLUSION

Three-weekly intravitreal topotecan appears effective and safe in controlling focal or diffuse refractory or recurrent vitreous seeds in retinoblastoma.

Ocular Salvage and Vision Preservation Using a Topotecan-Based Regimen for Advanced Intraocular Retinoblastoma

Purpose To evaluate topotecan-based therapy for advanced intraocular retinoblastoma. Patients and Methods Twenty-seven patients with bilateral retinoblastoma (male patients, n = 14; median age, 8.4 months) received chemotherapy: two courses of topotecan plus vincristine followed by three alternating administrations of carboplatin and vincristine for two courses and topotecan plus vincristine for one course, with optional periocular carboplatin. Focal therapy was applied after cycle 2. Event-free survival was defined as avoidance of external-beam radiotherapy (EBRT) and enucleation. Results Of 54 eyes, 42 were Reese-Ellsworth group IV to V, and 37 were International Classification of Retinoblastoma group C to E. Eleven eyes were enucleated: one at diagnosis, nine with progressive disease including three eyes treated with EBRT, and one that developed neovascular glaucoma after completion of therapy. One patient was removed from protocol with prolonged infection in course 1; 26 patients (51 eyes) were analyzed. At 10 years, cumulative incidence of EBRT was 5.9% (SE ± 3), and event-free survival was 69.2% (SE ± 27.2). Ocular survival for Reese-Ellsworth group IV to V eyes was 77.5% (SE ± 21.2); it was 74.3% (SE ≥ 18.8) for International Classification group C to E eyes. Vision testing (median age, 7 years; range, 5 to 10 years) documented 20/70 vision or better in one eye of 23 patients; 19 (76%) of 25 patients demonstrated 20/40 vision or better in one eye. All patients experienced thrombocytopenia (41 episodes in 275 courses; 15%). There were 29 episodes of febrile neutropenia (10%). Grade 3 diarrhea was present in nine of 27 patients, and one patient had an allergic reaction to carboplatin. All patients are alive at median follow-up 7.4 years (range, 2.7 to 10 years). Conclusion Topotecan combined with vincristine, carboplatin, and aggressive focal therapies is an effective regimen for the treatment of advanced retinoblastoma and results in globe salvage with vision. Toxicities were anticipated and managed with appropriate supportive care.

The role of intravitreal chemotherapy for retinoblastoma

Targeted therapy in retinoblastoma (RB) is widely accepted as the current management tool with an aim of increasing drug availability at the tumor location. Inevitably the effect is several times higher compared to systemic delivery of chemotherapeutic drugs and carries less systemic toxicity. Despite tremendous advancement in saving life, eye salvage in advanced RB especially with active vitreous seeds remains a challenge. The hypoxic environment of the vitreous and reduced vitreous concentration of the drugs delivered makes these tumor seeds resistant to chemotherapy. Direct delivery of chemotherapeutic drugs into the vitreous cavity aids to overcome these challenges and is progressively being accepted worldwide. However, intraocular procedure in RB was abandoned due to high risk of extraocular tumor dissemination. Recently, the forbidden therapeutic technique was re-explored and modified for safe use. Although eye salvage rate has tremendously improved after intravitreal chemotherapy (IVitC), retinal toxicity, and vision salvage are yet to be validated. In our preliminary report of intravitreal melphalan in 11 eyes, we reported 100% eye salvage and 0% recurrence with an extended 15 months mean follow-up. In this review, we analyzed published reports on IVitC in RB via PubMed, Medline, and conference proceedings citation index, electronic database search, without language restriction that included case series and reports of humans and experimental animal eyes with RB receiving IVitC.

Ocular topotecan pharmacokinetics following topical administration to rabbits for diffused anterior retinoblastoma

OBJECTIVES

We characterized and compared the in-vivo absorption of topotecan into the aqueous humor after instillation of aqueous and ointment formulations.

METHODS

A lanolin/petrolatum ointment was used. New Zealand rabbits were instilled with topotecan solution (6 μg, group A), a single 10 μg dose of topotecan ointment (group B) or with five 10 μg doses of topotecan ointment (group C). Aqueous humor samples were collected at different times. Corneal samples were collected only for group A. Topotecan was quantified using HPLC, and pharmacokinetic parameters were calculated. Acute corneal epithelial toxicity was assessed after multiple instillations of topotecan ointment.

KEY FINDINGS

Total topotecan maximum aqueous humor concentration (C_max ) was 16.1, 69.9 and 287 ng/ml in group A, B and C, respectively. A single dose of topotecan ointment increased threefold and sevenfold the aqueous humor C_max , and exposure compared to the aqueous formulation. Aqueous humor concentrations from group C eyes were substantially above the cytotoxic concentration for retinoblastoma cells. No corneal toxicity was evident after ointment instillation.

CONCLUSIONS

Topotecan penetrated into the aqueous humor of the rabbit eye after multiple doses of an ointment in concentrations pharmacologically active against retinoblastoma cells without eliciting acute toxicity. Topotecan ointment may translate to the clinical treatment of anterior segment disseminated retinoblastoma.

Sustained-release hydrogels of topotecan for retinoblastoma

Treatment of retinoblastoma, the most common primary ocular malignancy in children, has greatly improved over the last decade. Still, new devices for chemotherapy are needed to achieve better tumor control. The aim of this project was to develop an ocular drug delivery system for topotecan (TPT) loaded in biocompatible hydrogels of poly(ε-caprolactone)-poly(ethyleneglycol)-poly(ε-caprolactone) block copolymers (PCL-PEG-PCL) for sustained TPT release in the vitreous humor. Hydrogels were prepared from TPT and synthesized PCL-PEG-PCL copolymers. Rheological properties and in vitro and in vivo TPT release were studied. Hydrogel cytotoxicity was evaluated in retinoblastoma cells as a surrogate for efficacy and TPT vitreous pharmacokinetics and systemic as well as ocular toxicity were evaluated in rabbits. The pseudoplastic behavior of the hydrogels makes them suitable for intraocular administration. In vitro release profiles showed a sustained release of TPT from PCL-PEG-PCL up to 7days and drug loading did not affect the release pattern. Blank hydrogels did not affect retinoblastoma cell viability but 0.4% (w/w) TPT-loaded hydrogel was highly cytotoxic for at least 7days. After intravitreal injection, TPT vitreous concentrations were sustained above the pharmacologically active concentration. One month after injection, animals with blank or TPT-loaded hydrogels showed no systemic toxicity or retinal impairment on fundus examination, electroretinographic, and histopathological assessments. These novel TPT-hydrogels can deliver sustained concentrations of active drug into the vitreous with excellent biocompatibility in vivo and pronounced cytotoxic activity in retinoblastoma cells and may become an additional strategy for intraocular retinoblastoma treatment.

Targeting Survivin Enhances Chemosensitivity in Retinoblastoma Cells and Orthotopic Tumors

Treatments for retinoblastoma (Rb) vary depending on the size and location of the intraocular lesions and include chemotherapy and radiation therapy. We examined whether agents used to treat Rb induce a pro-survival phenotype associated with increased expression of survivin, a member of the inhibitor of apoptosis family of proteins. We document that exposure to carboplatin, topotecan or radiation resulted in elevated expression of survivin in two human Rb cell lines but not in normal retinal pigmented epithelial (RPE) cells. Cellular levels of survivin were attenuated in Rb cells exposed to an imidazolium-based survivin suppressant, Sepantronium bromide (YM155). Protein expression patterns of survivin in RPE cells were not altered following treatment protocols involving exposure to YM155. Including YM155 with chemotherapy or radiation increased levels of apoptosis in Rb cells but not in RPE cells. Intraocular luciferase expressing Rb tumors were generated from the Rb cell lines and used to evaluate the effects of carboplatin and YM155 on in-vivo survivin expression and tumor growth. Carboplatin induced expression of survivin while carboplatin combined with YM155 reduced survivin expression in tumor bearing eyes. The combination protocol was also most effective in reducing the rate of tumor regrowth. These results indicate that targeted inhibition of the anti-apoptotic protein survivin provides a therapeutic advantage for Rb cells and tumors treated with chemotherapy.

Chemoreduction of Progressive Intraocular Retinoblastoma by Systemic Topotecan

PURPOSE

To evaluate our experience with systemic Toptecan (TPT) chemotherapy as a second-line systemic chemotherapeutic regimen for treatment of refractory or recurrent intraocular retinoblastoma (RB).

METHODS AND MATERIALS

A retrospective case series of 14 eyes from patients with intraocular RB who received systemic TPT as second-line chemotherapy from April 2008 until June 2010. The following data were collected: patient demographics, laterality, international intraocular retinoblastoma stage (ICRB) at diagnosis, treatment received before and after TPT, side effects related to TPT, eye salvage, and survival.

RESULTS

The median age at diagnosis was 5 months (range, 1-16 months), and the median age at starting TPT was 10 months (range, 8-24 months). There were 6 (60%) females and 9 (90%) patients; all with bilateral retinoblastoma. The median number of TPT cycles was three per patient (range, 1-6), and the total number of administered cycles was 29. After TPT therapy; 4 (29%) eyes showed favorable response, 3 (21%) eyes showed minimal regression, 5 (36%) eyes had stable disease, and 2 (14%) eyes showed tumor progression. At a median follow-up of 48 months; 9 (64%) eyes were salvaged, 3 (21%) eyes received radiation therapy, and 3 (21%) eyes were enucleated (one was post radiation). Grade 3/4 neutropenia were noticed in a total of 59% of given cycles and admission for febrile neutropenia was required after seven cycles.

CONCLUSIONS

Our report suggests that systemic TPT chemotherapy could be used as a salvage second-line regimen with low toxicity for patients with progressive intraocular retinoblastoma if systemic therapy is needed.

Intravitreal Topotecan Inhibits Laser-induced Choroidal Neovascularization in a Rat Model

Purpose:

A two-phase preclinical study was designed to determine the safe dose of intravitreal topotecan and its inhibitory effect on experimental choroidal neovascularization (CNV) in a rat model.

Methods:

In phase I, 42 rats were categorized into 6 groups, 5 of which received intravitreal topotecan injections of 0.125 μg, 0.25 μg, 0.5 μg, 0.75 μg, and 1.0 μg/5 μl, respectively; the control group received an injection of normal saline. Ophthalmic examination and electroretinography (ERG) were performed on days 7 and 28, and enucleated globes were processed for histopathology and immunostaining for glial fibrillary acidic protein. In phase II, CNV was induced via laser burns in 20 rats and the animals were divided into 2 groups. One group received topotecan and the other received normal saline intravitreally. Four weeks later, mean scores of fluorescein leakage on fluorescein angiography as well as mean CNV areas on histology sections were compared.

Results:

In phase I, clinical, ERG and histopathologic results were unremarkable in terms of retinal toxicity in all groups. Based on the results of phase I, a dose of 1 μg/5 μl topotecan was chosen for phase II. Leakage scores obtained from late-phase fluorescein angiography were significantly lower in topotecan-treated than control eyes (P < 0.01) four weeks after induction of CNV. Compared to control eyes, topotecan-treated eyes showed a significantly lower incidence of fibrovascular proliferation (8.7% vs. 96.2%) and significantly smaller areas of CNV (P < 0.01).

Conclusion:

Intravitreal injection of topotecan at a dose of 1 μg/5 μl is safe and may be a promising treatment for CNV.

Hypersensitivity to sub-Tenon's topotecan in fibrin adhesive in patients with retinoblastoma

Sub-Tenon's space delivery of topotecan in a fibrin sealant was used as an adjunct to laser therapy for small retinoblastoma tumors in 25 children (77 injections). We report serious hypersensitivity reactions in 2 children on their third sub-Tenon's injection of topotecan in fibrin sealant. One child subsequently had topotecan in an autologous blood clot with no allergic reaction. Although allergic reaction to topotecan has been reported in the literature, fibrin glue reactions are more common and are likely due to aprotinin hypersensitivity.

Risk of subsequent malignant neoplasms in long-term hereditary retinoblastoma survivors after chemotherapy and radiotherapy

PURPOSE

Hereditary retinoblastoma (Rb) survivors have increased risk of subsequent malignant neoplasms (SMNs). Previous studies reported elevated radiotherapy (RT) -related SMN risks, but less is known about chemotherapy-related risks.

PATIENTS AND METHODS

In a long-term follow-up study of 906 5-year hereditary Rb survivors diagnosed from 1914 to 1996 and observed through 2009, treatment-related SMN risks were quantified using cumulative incidence analyses and multivariable Cox proportional hazards regression models with age as the underlying time scale.

RESULTS

Nearly 90% of Rb survivors were treated with RT, and almost 40% received alkylating agent (AA) -containing chemotherapy (predominantly triethylenemelamine). Median follow-up time to first SMN diagnosis was 26.3 years. Overall SMN risk was not significantly elevated among survivors receiving AA plus RT versus RT without chemotherapy (hazard ratio [HR], 1.27; 95% CI, 0.99 to 1.63). AA-related risks were significantly increased for subsequent bone tumors (HR, 1.60; 95% CI, 1.03 to 2.49) and leiomyosarcoma (HR, 2.67; 95% CI, 1.22 to 5.85) but not for melanoma (HR, 0.74; 95% CI, 0.36 to 1.55) or epithelial tumors (HR, 0.89; 95% CI, 0.48 to 1.64). Leiomyosarcoma risk was significantly increased for survivors who received AAs at age < 1 (HR, 5.17; 95% CI, 1.76 to 15.17) but not for those receiving AAs at age ≥ 1 year (HR, 1.75; 95% CI, 0.68 to 4.51). Development of leiomyosarcoma was significantly more common after AA plus RT versus RT (5.8% v 1.6% at age 40 years; P = .01).

CONCLUSION

This comprehensive quantification of SMN risk after chemotherapy and RT among hereditary Rb survivors also demonstrates an AA-related contribution to risk. Although triethylenemelamine is no longer prescribed, our findings warrant further follow-up to investigate potential SMN risks associated with current chemotherapies used for Rb.

Carboplatin +/- topotecan ophthalmic artery chemosurgery for intraocular retinoblastoma

Purpose

Carboplatin administered systemically or periocularly can result in dramatic and prompt regression of retinoblastoma. However, both routes are rarely curative alone and have undesirable side effects. We aimed to assess the efficacy and toxicity of carboplatin +/− topotecan delivered by ophthalmic artery chemosurgery whereby chemotherapy is infused into the eye via the ophthalmic artery.

Methods

This retrospective, IRB-approved study investigated retinoblastoma patients whom received carboplatin +/− topotecan ophthalmic artery chemosurgery. Patient survival, ocular survival, hematologic toxicity, ocular toxicity, second cancer development and electroretinogram response were all evaluated.

Results

57 carboplatin +/− topotecan infusions (of 111 total) were performed in 31 eyes of 24 patients. The remaining infusions were melphalan-containing. All patients were alive and no patient developed a second malignancy at a median follow up of 25 months. The Kaplan-Meier estimate of ocular survival at two years was 89.9% (95% confidence interval [CI], 82.1–97.9%) for all eyes. Grade 3 or 4 neutropenia developed in two patients and one patient developed metastatic disease. By univariate analysis, neither increasing maximum carboplatin/topotecan dose nor cumulative carboplatin/topotecan dose was associated with statistically significant reduction in the electroretinogram responses.

Conclusion

Carboplatin +/− topotecan infusions are effective for ophthalmic artery chemosurgery in retinoblastoma: they demonstrate low hematologic and ocular toxicity and no statistically significant influence on electroretinogram responses, and used in conjunction with melphalan-containing OAC, demonstrate excellent patient survival and satisfactory ocular survival.

Intra-arterial chemotherapy is more effective than sequential periocular and intravenous chemotherapy as salvage treatment for relapsed retinoblastoma

BACKGROUND

Treatment of eyes with retinoblastoma failing systemic chemoreduction and external beam radiotherapy is seldom efficacious. This study compares the efficacy and toxicity of intra-arterial ophthalmic artery chemotherapy (IAO) to our historical cohort of sequential periocular and systemic chemotherapy in such patients.

PATIENTS AND METHODS

Eighteen eyes (15 consecutive patients) were retrospectively evaluated. Eight eyes received IAO for a median of four cycles (range: 2-9) including melphalan alone (n = 3) or after topotecan and carboplatin (n = 4) or topotecan and carboplatin without melphalan (n = 1). Ten eyes received a median of two cycles (range: 1-3) of periocular topotecan (n = 9) or carboplatin (n = 1) followed by intravenous topotecan and cyclophosphamide in three patients if at least stable disease was achieved. Both groups were comparable for disease extension and prior therapy.

RESULTS

No extraocular dissemination or second malignancy occurred and all patients are alive. The probability of enucleation-free eye survival at 12 months was 0.87 (95% CI: 0.42-0.97) for the IAO group, compared to 0.1 (95% CI: 0.06-0.35) for the periocular group (P < 0.01). Ocular toxicity was mild and similar in both groups (mostly mild orbital edema). Systemic toxicity was low for IAO and periocular injection, but children who received sequentially intravenous chemotherapy (n = 12 cycles) had five episodes of grade 4 neutropenia, three of which resulted in hospitalizations. No case in the IAO group presented these complications.

CONCLUSIONS

IAO is significantly superior to sequential periocular-intravenous topotecan-containing regimens in eyes with relapsed intraocular retinoblastoma with a more favorable toxicity profile.

Topotecan and vincristine combination is effective against advanced bilateral intraocular retinoblastoma and has manageable toxicity

BACKGROUND

New, effective chemotherapeutic agents are needed for intraocular retinoblastoma.

METHODS

This institutional clinical trial sought to estimate the rate of response to 2 courses of vincristine and topotecan (VT) window therapy in patients with bilateral retinoblastoma and advanced disease (Reese-Ellsworth group IV or V) in at least 1 eye. The topotecan dose started at 3 mg/m(2) /day for 5 days and was adjusted to target a systemic exposure of 140 ± 20 ng/mL · hour. The vincristine dose was 0.05 mg/kg for patients <12 months of age and 1.5 mg/m(2) for those >12 months of age at diagnosis.

RESULTS

From February 2005 to June 2010, 27 patients received VT window therapy. Median age at enrollment was 8.1 months (range, 0.7-22.1 months). Twenty-four patients (88.9%) responded to window therapy (95% confidence interval = 71.3%-96.9%). Hematologic toxicity comprised grade 4 neutropenia (n = 27), grade 3 anemia (n = 19), and grade 3/4 thrombocytopenia (n = 16). Thirteen patients had grade 3 nonhematologic toxicity. Granulocyte colony-stimulating factor support was added after 10 patients had been treated, and it significantly reduced the duration of grade 4 neutropenia (median, 7 vs 24 days; P < .001). Pharmacokinetic studies showed rapid changes in topotecan clearance rates during the first year of life.

CONCLUSIONS

The combination of topotecan and vincristine is effective for the treatment of advanced intraocular retinoblastoma. Granulocyte colony-stimulating factor treatment alleviates the duration of grade 4 neutropenia. Appropriate topotecan starting doses for patients 0-3, 3-6, 6-9, 9-12, and >12 months of age are specified.

Pharmacokinetic analysis of topotecan after superselective ophthalmic artery infusion and periocular administration in a porcine model

PURPOSE

To characterize the vitreous and plasma pharmacokinetics of topotecan after ophthalmic artery infusion (OAI) subsequent to superselective artery catheterization and to compare it with periocular injection (POI).

METHODS

The ophthalmic artery of 4 pigs was catheterized and 1 mg of topotecan infused over a period of 30 minutes. The contralateral eye was subsequently used for administering topotecan by POI. Serial vitreous specimens were obtained by microdialysis and plasma samples collected and assayed for total and lactone topotecan.

RESULTS

Maximum total topotecan concentration in the vitreous (median, range) was significantly higher after OAI compared with POI (131.8 ng/mL [112.9-138.7] vs. 13.6 ng/mL [5.5-15.3], respectively; P < 0.005). Median vitreous exposure calculated as area under the curve for total topotecan attained after OAI was significantly higher than after POI (299.8 ng·hour/mL [247.6-347.2] and 48.9 ng·hour/mL [11.8-63.4], respectively; P < 0.05). The vitreous to plasma exposure ratio was 29 after OAI and 3.4 after POI. Systemic exposure for total topotecan was low after both modalities of administration, with a trend to be lower after OAI compared with POI (10.6 ng·hour/mL [6.8-13.4] vs. 18.7 ng·hour/mL [6.3-21.7]; P = 0.54).

CONCLUSION

Superselective OAI resulted in significantly higher vitreous concentrations and exposure and a trend toward lower systemic exposure than POI.

Ethnicity is a factor to be considered before dose planning in ovarian cancer patients to be treated with topotecan

The objective of this study was to determine the efficacy and toxicity of topotecan in Chinese patients with ovarian cancer. A retrospective analysis on recurrent ovarian cancer patients receiving topotecan 1.25 mg/m(2) daily for 5 consecutive days on a 21-day cycle from 1997 to 2002 was conducted. The patients included were all treated with at least two cycles of topotecan. The patient characteristics were compared in relation to their toxicity profile and their response to treatment. Response was evaluated by physical findings, imaging techniques, and serum CA125 level. A total of 60 patients were included in the study. All patients were evaluable for response and toxicities. A total of 361 cycles were given (median, 5 per patient; range 2-15). The major toxicity was neutropenia, which was grade 4 in 45.0% of the patients and 10.2% of the cycles. Age was the only covariate predicting the occurrence of grade 4 neutropenia (logistic regression P= 0.046, CI 1.01-1.12). Neutropenic fever occurred in 8.3% of the patients. Eighteen (30%) patients were required to delay their chemotherapy and 11 (18.3%) required dose reduction. Nonhematologic toxicities were mild. The overall response rate was 21.6%, with eight (13.3%) complete responses and five (8.3%) partial responses. The median duration of response and median time to progression were 11 and 5 months, respectively. The median survival was 14 months. Topotecan 1.25 mg/m(2) in a five-times-daily schedule was well tolerated in a cohort of Chinese patients. Myelotoxicity was the most important side effect in our study, but the incidence is much lower than that reported in other studies. Age was an independent factor predicting the occurrence of grade 4 neutropenia.

Topotecan Combination Chemotherapy in Two New Rodent Models of Retinoblastoma

Chemotherapy combined with laser therapy and cryotherapy has improved the ocular salvage rate for children with bilateral retinoblastoma. However, children with late-stage disease often experience recurrence shortly after treatment. To improve the vision salvage rate in advanced bilateral retinoblastoma, we have developed and characterized two new rodent models of retinoblastoma for screening chemotherapeutic drug combinations. The first model is an orthotopic xenograft model in which green fluorescent protein- or luciferase-labeled human retinoblastoma cells are injected into the eyes of newborn rats. The second model uses a replication-incompetent retrovirus (LIA-E(E1A)) encoding the E1A oncogene. Clonal, focal tumors arise from mouse retinal progenitor cells when LIA-E(E1A) is injected into the eyes of newborn p53-/- mice. Using these two models combined with pharmacokinetic studies and cell culture experiments, we have tested the efficacy of topotecan combined with carboplatin and of topotecan combined with vincristine for the treatment of retinoblastoma. The combination of topotecan and carboplatin most effectively halted retinoblastoma progression in our rodent models and was superior to the current triple drug therapy using vincristine, carboplatin, and etoposide. Vincristine had the lowest LC50 in culture but did not reduce tumor growth in our preclinical retinoblastoma models. Taken together, these data suggest that topotecan may be a suitable replacement for etoposide in combination chemotherapy for the treatment of retinoblastoma.

Experience with chemoreduction and focal therapy for intraocular retinoblastoma in a developing country

BACKGROUND

Chemoreduction is used for the treatment of retinoblastoma in industrialized nations; however, there are fewer data from developing countries. Before the implementation of this program, radiotherapy was used in almost all preserved eyes.

METHODS

Retrospective evaluation from 1995 to 2001 at the Hospital Garrahan (Argentina). Carboplatin 18.7 mg/kg/day 1 and vincristine (0.05 mg/kg/day 1) were offered to patients with Reese-Ellsworth (RE) groups I-III and all unilateral cases. Etoposide (3.3 mg/kg/day 1 and 2) was added for groups IV and V. The number of cycles was tailored according to response.

RESULTS

Fifty-eight patients (78 eyes) were evaluated (39 bilateral, 19 unilateral). With a median follow-up of 47 months, 40 patients had unilateral enucleation, 14 were not enucleated, and 4 had bilateral enucleation. Nineteen patients had unilateral initial enucleation. Eye preservation at 5 years was: RE groups I-III (n = 24 eyes), 0.9 (SE: 0.095) IV-V (n = 54), 0.45 (SE 0.07). Patients received a median of four cycles of chemotherapy. Acute toxicity was mild. External beam radiotherapy was avoided in 41% of eyes with groups I-III. Etoposide was avoided in 24 patients. Two patients died of metastasis. No secondary malignancy occurred.

CONCLUSIONS

Compared to our previous experience, eye preservation was better and even though less radiotherapy was used, it was prescribed more often than currently recommended in eyes with less advanced disease because of limited availability of sophisticated local therapy.