Characterization of the peripheral neuropathy associated with brentuximab vedotin treatment of Mycosis Fungoides and Sézary Syndrome.

Chemotherapy-induced peripheral neuropathy (CIPN) is common, frequently limits chemotherapy dosing, and negatively impacts quality of life. The National Cancer Institute Common Toxicity Criteria for Adverse Events (CTCAE), version 4.0, and the Total Neuropathy Score clinical version (TNSc) are both validated scores to quantify peripheral neuropathy (PN), with the TNSc being more sensitive to clinical changes. Mycosis fungoides and Sézary syndrome (MF/SS) are characterized by a chronic course, where current therapies are generally non-curative and treatment toxicities have the potential for significant lasting effects. Brentuximab vedotin (BV) is an antibody-drug-conjugate composed of an anti-CD30 monoclonal antibody linked to the microtubule-disrupting agent, monomethyl auristatin E, with a known associated CIPN. In our phase II clinical trial of BV in MF/SS, 25 (69%) of 36 patients developed PN, with 18 (50%) developing Clinically Significant PN, CTCAE v4.0 grade 2 or higher. The median time to grade 2 PN was 15 weeks (range 0.4-48) after the initial dose. By Kaplan-Meier calculation, the median time to improvement from Clinically Significant PN was 30 weeks from the last BV dose. Seventy-four percent had improvement by 24 months. We found that TNSc scores significantly correlated with CTCAE grade, with Spearman correlation coefficient 0.68 (p < 0.001). By logistic regression, for each 100 mg increase in BV total dose, the likelihood of developing Clinically Significant PN increased by 23% (95% CI 4-46%). Improved monitoring of CIPN associated with BV is of paramount importance in the MF/SS population.

Phase II Investigator-Initiated Study of Brentuximab Vedotin in Mycosis Fungoides and Sézary Syndrome With Variable CD30 Expression Level: A Multi-Institution Collaborative Project.

PURPOSE: In contrast to Hodgkin lymphoma and systemic anaplastic large-cell lymphoma, CD30 expression of malignant lymphocytes in mycosis fungoides (MF) and Sézary syndrome (SS) is quite variable. Clinical activity and safety of brentuximab vedotin, a CD30 targeting antibody-drug conjugate, was evaluated in MF and SS. Tissue and blood biomarkers of clinical response were explored. PATIENTS AND METHODS: In this phase II study, patients with MF or SS with negligible to 100% CD30 expression levels were treated with brentuximab vedotin (1.8 mg/kg) every 3 weeks for a maximum of sixteen doses. The primary end point was overall global response rate. Secondary end points included correlation of tissue CD30 expression level with clinical response, time to response, duration of response, progression-free and event-free survivals, and safety. RESULTS: Of the 32 patients enrolled and treated, 30 patients had available efficacy evaluations. Objective global response was observed in 21 (70%) of 30 patients (90% CI, 53% to 83%). CD30 expression assessed by immunohistochemistry was highly variable, with a median CD30max of 13% (range, 0% to 100%). Those with <5% CD30 expression had a lower likelihood of global response than did those with 5% or greater CD30 expression (P < .005). CD163 positive tumor-associated macrophages, many of which coexpress CD30, were abundant in tissue. Peripheral neuropathy was the most common adverse event. CONCLUSION: Brentuximab vedotin demonstrated significant clinical activity in treatment-refractory or advanced MF or SS with a wide range of CD30 expression levels. Additional biomarker studies may help optimize rational design of combination therapies with brentuximab vedotin.