Rituximab treatment for chronic refractory idiopathic thrombocytopenic purpura

Successful Management of Immune Thrombocytopenia Presenting with Lethal Alveolar Hemorrhage

Immune thrombocytopenic purpura (ITP) typically presents with bleeding due to immunologic thrombocytopenia. Severe hemorrhage due to ITP is sometimes lethal, and the urgent recovery of platelets is necessary. In addition to conventional therapeutic strategies, romiplostim shows promising efficacy for chronic ITP. However, there is little evidence for the utilization of this treatment for acute ITP or acute exacerbation of chronic ITP. We report the case details of three elderly ITP patients presenting with lethal diffuse alveolar hemorrhage. These patients had the following underlying pulmonary diseases: case 1, nontuberculous mycobacterial infection and sarcoidosis; case 2, cryptogenic organizing pneumonia; case 3, pulmonary emphysema. These patients recovered following treatment with romiplostim at a higher dose (10 μg/kg), in addition to conventional therapies including corticosteroids and high-dose intravenous immunoglobulin. In summary, the addition of romiplostim resulted in earlier recovery of thrombocytopenia than has been previously reported. Our three cases suggest that early romiplostim at a higher dose could be an efficacious therapeutic option for acute ITP patients with severe lethal bleeding.

Low Dose Rituximab in Chronic ITP: Still an Option in Resource Limited Settings

The etiology of ITP remains unknown but its pathogenesis consists of loss of tolerance to platelet antigens. There is a complex dysregulation of the immune system involving both the B cells and the T cells. Splenectomy is the standard second line option in steroid refractory chronic ITP patients. However, costs of surgery and reluctance for surgery in severely thrombocytopenic patients on part of surgeons are major obstacles in resource limited settings. Rituximab has been used in both the standard doses of 375 mg/m² and low doses of 100 mg/m² with similar results. We studied the utility of low dose Rituximab (@100 mg/m² weekly × 4 doses) in resource limited settings. Overall response, complete response (CR) and partial response (PR) rates were 47.6% (10/21), 33.3% (7/21) and 14.3% (3/21) respectively. Median time to response in patients achieving CR was 75 days (range 45-185 days) while in patients achieving PR it was 105 days (range 45-165 days). However, there was no significant difference between males and females achieving CR or PR. We also observed that patients who had earlier responded to any form of treatment were more likely to respond to Rituximab treatment. The cumulative relapse free survival (RFS) at 13 months was 78%. By giving lower dose, six times less than conventional dosing dose, we have been able to demonstrate cost effectiveness in our study population. We were able to administer all the doses in day care without any major adverse events leading to further cost savings on in-patient care.

Different dosages of intravenous immunoglobulin (IVIg) in treating immune thrombocytopenia with long-term follow-up of three years: Results of a prospective study including 167 cases

This study compared the effects of different dosages of intravenous immunoglobulin (IVIg) against immune thrombocytopenia (ITP). A total of 167 patients, 91 adults and 76 children, with ITP, followed-up for three years in the case-control study, were divided into three subgroups according to the dosages of IVIg administered: group A (0.2 g/kg/day), group B (0.3 g/kg/day) and group C (0.4 g/kg/day). The therapeutic response in 91 adult patients did not differ significantly among the three groups of IVIg dosages (p = 0.459). The response rate of IVIg treatment in the three adult groups was 97.1% for group A, 97.2% for group B and 100% for group C. The mean time for raising platelets to 30 × 10(9)/L in group A was 2.5 days, group B 3.2 days and group C 2.9 days (p = 0.324). The median IVIg consumption in group A was 0.83 g/kg, group B 1.22 g/kg and group C 1.64 g/kg (p < 0.01). Similar results were shown in the children groups. The follow-up results showed no significant difference of clinical outcome between groups A, B and C. In conclusion, low-dose IVIg treatment is shown to be as effective as high-dose regimen without increasing the risk of developing the patients into chronic ITP conditions, suggesting that ITP patients could be treated more cost-effectively by lower conventional dosage of IVIg regimen.

[Efficacy and safety of rhTPO in the treatment of pediatric primary immune thrombocytopenia]

OBJECTIVE

To evaluate the efficacy and safety of recombinant human thrombopoietin (rhTPO) in treatment of pediatric primary immune thrombocytopenia (ITP).

METHODS

The clinical characteristics of 41 pediatric ITP patients who received rhTPO therapy from December 2006 to September 2014 were retrospectively analyzed (as rhTPO group). During the same time another 26 pediatric ITP patients who received vindesine combined with human immunoglobulin therapy were selected as control group. The treatment outcomes were evaluated.

RESULTS

A total of 67 cases of pediatric ITP, 31 males and 36 females with a median age 10.0(1.6-17.0) years were enrolled, including 19 cases of newly disgnosed ITP, 18 cases of persistent ITP and 30 cases of chronic ITP. Of them, 43 cases of whom were severe ITP (PLT<10×10⁹/L). The total response rate had no statistically significant difference between the rhTPO group and the control group (68.29% vs 65.38%, P=0.806), neither in newly ITP, persistent and chronic ITP (P=0.320, P=0.763). In severe ITP patients, 17 of 30 cases (56.67%) achieved response with rhTPO therapy, while the control group was 61.54% (8/13) (P=0.766). The median maximum peak of platelet counts and the time of the platelet counts >30×10⁹/L and > 50×10⁹/L had no statistically significant differences in rhTPO group compared with the control group [52(7-608)×10⁹/L vs 40(3-152)×10⁹/L, P=0.05; 7(3-13) d vs 4(2-24) d, P=0.202; 7.5(4-15) d vs 5.5(4-23) d, P=0.557]. The mean platelet counts were 43(3-605)×10⁹/L in the rhTPO group, which were higher than the control group [32(-14-149)×10⁹/L, P=0.042]. No severe adverse effects were observed in both groups.

CONCLUSION

For pediatric ITP, rhTPO has a similar outcomes with vindesine combined with human immunoglobulin, and it is an effective and safe treatment option.

[Cost per responder associated with romiplostim and rituximab treatment for adult primary immune thrombocytopenia in France]

PURPOSE OF THE STUDY

This analysis compared the response rates and cost per responder associated with romiplostim and rituximab in adult immune thrombocytopenia from the French National Health System payer perspective.

METHODS

A decision analytic model was developed to estimate the cost per patient and per responder of treating adult immune thrombocytopenia patients with romiplostim versus rituximab over 6 months. A systematic literature review identified phase 3 randomized controlled trials. Published response rates were extracted (response definition: ≥50×10(9) platelets/liter). Resource utilization was based on French and international treatment guidelines, and clinical expert opinion. Unit costs were derived from literature and French reimbursement lists, and included the costs of routine physician visits, treatment administration, and emergency care. Non-responders incurred bleeding-related event costs.

RESULTS

The literature review identified a phase 3 randomized controlled trial for romiplostim with a response rate of 83%. Due to a lack of phase 3 randomized controlled trials for rituximab, a systematic review of studies was selected as the best source, reporting a response rate of 62.5%. Romiplostim and rituximab were associated with similar treatment costs, with an estimated cost per patient for romiplostim of €17,456 and €17,068 for rituximab. Rituximab resulted in a 30% higher cost per responder (€27,308 for rituximab versus €21,031 for romiplostim). Romiplostim use reduced drug administration, intravenous immunoglobulin, and bleeding-related hospitalization costs compared to rituximab.

CONCLUSIONS

Due to its high efficacy leading to lower bleeding-related costs, romiplostim represents an efficient use of resources for adult immune thrombocytopenia patients in the French healthcare system.

[Cost-per-responder analysis comparing romiplostim to rituximab in the treatment of adult primary immune thrombocytopenia in Spain]

BACKGROUND AND OBJECTIVE

Romiplostim, a thrombopoietin-receptor agonist, is approved for second-line use in idiopathic thrombocytopenic purpura (ITP) patients where surgery is contraindicated. Anti-CD20 rituximab, an immunosuppressant, is currently used off-label. This analysis compared the cost per responder for romiplostim versus rituximab in Spain.

MATERIALS AND METHOD

A decision analytic model was constructed to estimate the 6-month cost per responding patient (achieving a platelet count≥50×10(9)/l) according to the most robust published data. A systematic literature review was performed to extract response rates from phase 3 randomized controlled trials. Romiplostim patients received weekly injections; rituximab patients received 4 weekly intravenous infusions. Medical resource costs were obtained from Spanish reimbursement lists. Treatment non-responders incurred bleeding-related event (BRE) management costs as reported in clinical trials. Medical resource utilization and clinical practice were based on Spanish treatment guidelines and validated by local clinical experts.

RESULTS

The literature review identified phase 3 romiplostim trials with a response rate of 83%. Due to a lack of phase 3 controlled rituximab trials, a systematic review of studies was selected as the best source, reporting a response rate of 62.5%. The mean cost per patient for romiplostim was €16,289 and €13,459 for rituximab. Rituximab resulted in a 10% higher cost per responder (€21,535 versus €19,625 for romiplostim). Romiplostim use reduced drug administration, intravenous immunoglobulin, and bleeding-related costs compared to rituximab.

CONCLUSIONS

Due to its high level of efficacy leading to lower BRE costs, romiplostim represents an efficient use of resources for adult ITP patients in the Spanish Healthcare System.

Cost effectiveness of romiplostim for the treatment of chronic immune thrombocytopenia in Ireland

BACKGROUND

Romiplostim, a thrombopoietin receptor agonist (TPOra), is a second-line medical treatment option for adults with chronic immune thrombocytopenia (ITP). Clinical trials have shown that romiplostim increases platelet counts, while reducing the risk of bleeding and, in turn, the need for costly rescue medications.

AIMS

The objective of this study was to assess the cost effectiveness of romiplostim in the treatment of adult ITP in Ireland, in comparison with eltrombopag and the medical standard of care (SoC).

METHODS

A lifetime treatment-sequence cost-utility Markov model with embedded decision tree was developed from an Irish healthcare perspective to compare romiplostim with eltrombopag and SoC. The model was driven by platelet response (platelet count ≥50 × 10(9)/L), which determined effectiveness and progression along the treatment pathway, need for rescue therapy (e.g. intravenous immunoglobulin [IVIg] and steroids) and risk of bleeding. Probability of response, mean treatment duration, average time to initial response and utilities were derived from clinical trials and other published evidence. Treatment sequences and healthcare utilization practice were validated by Irish clinical experts. Costs were assessed in <euro> for 2011 and included drug acquisition costs and costs associated with monitoring patients and management of bleeding, as available from published Irish reimbursement lists and other relevant sources. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

Romiplostim treatment resulted in an average of 20.2 fewer administrations of rescue medication (IVIg or intravenous steroids) over a patient lifetime than eltrombopag, and 29.3 fewer rescue medication administrations than SoC. Romiplostim was dominant, with cost savings of <euro>13,258 and <euro>22,673 and gains of 0.76 and 1.17 quality-adjusted life-years (QALYs), compared with eltrombopag and SoC, respectively. Romiplostim remained cost effective throughout a variety of potential scenarios, including short-term TPOra treatment duration (1 year). One-way sensitivity analysis showed that the model was most sensitive to variation in the cost of IVIg and use of romiplostim and IVIg. Probabilistic sensitivity analysis showed that romiplostim was likely to be cost effective in over 90 % of cases compared with eltrombopag, and 96 % compared with SoC at a willingness-to-pay threshold of <euro>30,000 per QALY.

CONCLUSIONS

Use of romiplostim in the ITP treatment pathway, compared with eltrombopag or SoC, is likely to be cost effective in Ireland. Romiplostim improves clinical outcomes by increasing platelet counts, reducing bleeding events and the use of IVIg and steroids, resulting in both cost savings and additional QALYs when compared with current treatment practices.

ITP in children: pathophysiology and current treatment approaches

Primary immune thrombocytopenia (ITP) is one of the most common bleeding disorders of childhood. In most cases, it presents with sudden widespread bruising and petechiae in an otherwise well child. Thought to be mainly a disorder of antibody-mediated platelet destruction, ITP can be self-limited or develop into a chronic condition. In this review, we discuss current concepts of the pathophysiology and treatment approaches to pediatric ITP.

Treatment of immune thrombocytopenic purpura: focus on eltrombopag

Immune thrombocytopenic purpura (ITP) is a relatively common autoimmune disorder in which antibodies are produced to circulating platelets. Symptoms can be mild, but for most patients the risk of severe bleeding is unacceptable and treatment is required. Glucocorticoids followed by splenectomy had been the mainstays of therapy. High dose intravenous immunoglobulin and anti-RhD therapy are available for patients with severe illness, but produce only temporary benefit. Rituximab may provide more durable responses, danazol may be underutilized, and immunosuppressants and cytotoxic agents are less often required. Recently the pathophysiology of ITP has been more clearly elucidated, particularly the importance of decreased production of platelets in most patients and the very blunted rise that occurs in serum thrombopoietin (TPO). The isolation of TPO and better understanding of its role in thrombopoiesis has led to the development of new highly effective treatments. TPO analogs had some successes in treating highly refractory ITP patients but were taken out of development due to TPO-antibody induction. Two second-generation TPO-mimetics, romiplostim and the orally available eltrombopag, have recently been licensed in some territories for the treatment of ITP. Approval of eltrombopag was based on results from Phase II and III placebo-controlled clinical trials and a long-term extension study. About 80% of patients achieve significant increases in platelet count (11% of placebo patients), with reduced bleeding and reduced use of concomitant medications; responses are often durable with no tachyphylaxis. The side effects of eltrombopag are generally mild and not worse than placebo, although there are concerns about hepatic dysfunction, and the potentials for thromboses, marrow reticulin fibrosis, rebound thrombocytopenia and cataracts. This is an important new option for highly refractory patients, and its niche in earlier treatment (and for other thrombocytopenic disorders) is yet to be defined.

Off-label use of rituximab in a tertiary Queensland hospital

BACKGROUND

Rituximab is a monoclonal antibody directed against CD20, a pan B lymphocyte marker. It is approved in Australia for treatment of CD20-positive B cell non-Hodgkin lymphoma and rheumatoid arthritis. There is increasing off-label use of rituximab in conditions where B cells and autoantibodies play a role in the pathophysiology. Rituximab is not only expensive, but its safety in unregistered indications is uncertain.

METHODS

We performed a retrospective review of the off-label use of rituximab approved by the High Cost Drug Subcommittee at the Princess Alexandra Hospital between 2005 and 2008. Cases of post transplant lymphoproliferative disorder were excluded.

RESULTS

A total of 28 patients received rituximab for a variety of off-label indications. There were no reported cases of serious infusion reactions or other notable adverse events. The most favourable outcomes were seen in myasthenia gravis, shrinking lung syndrome, thrombotic thrombocytopenic purpura, prevention and treatment of renal transplant rejection and lupus nephritis. No benefit was observed in cases of focal segmental glomerulosclerosis (primary or post-transplant recurrence) and post-transplant recurrence of haemolytic uremic syndrome. There was limited benefit in cryoglobulinaemic vasculitis. The cost of off-label use was in excess of $210,000.

CONCLUSION

In the absence of formal clinical trials, decisions regarding off-label use of rituximab are difficult. Our cases contribute to the published literature and should help provide clinicians with greater insights into which conditions are likely to respond. As can be seen in our series, rituximab benefits people with certain conditions; longevity and cost-effectiveness are currently unknown.

The efficacy of rituximab in patients with splenectomized refractory chronic idiopathic thrombocythopenic purpura

The most difficult problem a physician encounters is the management of patients with idiopathic thrombocytopenic purpura (ITP), who has persistent severe thrombocytopenia after failure of initial treatment with glucocorticoids and splenectomy. Most of the patients refractory to corticosteroids and splenectomy will become refractory to other available agents, such as intravenous immunoglobulin (IVIg), danazol or chemotherapy. In this study, we investigated the effect of rituximab on 17 splenectomized refractory chronic ITP patients. Here, we showed that the anti-CD20 antibody, rituximab, induces a clinically significant response in severe chronic ITP patients, who are unresponsive to other therapeutic options. After sixth month, 10 out of 14 responders were still maintaining their durable and significant platelet responses (platelet counts >50 x 10(9)/l), without requirement to any other ITP medication. Therefore, we suggest that, rituximab is an effective treatment option in splenectomized refractory or relapsed ITP patients. Rituximab was well tolerated without severe side effects.