Italian Real Life Experience with Brentuximab Vedotin: Results of a National Observational Study on Relapsed/Refractory Anaplastic Large Cell Lymphoma

From November 2012 to July 2014, brentuximab vedotin (BV) was available in Italy for patients with relapsed systemic anaplastic large cell lymphoma (ALCL) outside a clinical trial context based on a local disposition of the Italian Drug Agency (AIFA) issued according to a national law (Law 648/96: "medicinal products that are provided free of charge on the national health service"). A large Italian observational retrospective study was conducted on the use of BV in the everyday clinical practice to check if clinical trial results are confirmed even in a real life context. Primary endpoint was the best response; secondary endpoints were the overall response rate at the end of the treatment, duration of response, survival and the safety profile. BV was infused intravenously at the dose of 1.8 mg/kg every 3 weeks for a maximum of 16 cycles. A total of 40 ALCL (18 anaplastic lymphoma kinase [ALK] negative and 22 ALK-positive status) patients were treated with BV in 40 Hematology Centers. All patients had histologically documented CD30+ ALCL; 16 (40%) had relapsed and 24 (60%) had refractory disease. Patients were heavily pretreated with a median of 2 previous therapies (including autologous transplant in the 32.5% of cases). Best response was observed after a median of 4 cycles in 31 patients (77.5%): 19 (47.5%) patients obtained a complete response (CR) and 12 (30%) achieved a partial response (PR); overall response rate at the end of the treatment was 62.5% (18 CR and 7 PR). The best response rate was higher in the elderly subset (>60 years): 9 (64.2%) CR and 3 (21.4%) PR, achieving a total of 85.6%. At the latest follow up 15/18 patients are still in CR (3 with consolidative procedure). Global progression free survival was 39.1% at 29 months and disease free survival 54% at 23.9 months (median not reached). Median duration of response was 12 months (range 9-24 months). We identified 5 long term responders (patients with a response ≥ 12 months), all were still in CR at the latest follow up (1 underwent allogeneic transplant). Particularly, all the long term responders were aged <30 years at first BV infusion.

All patients were included in the safety profile for the analysis; in general, the treatment was well tolerated even in this real life context and the toxicity profile was closely similar to the previously published data; no death has been linked to BV toxicity. Toxicity was primarily neurological and rarely so serious as to require treatment reduction or interruption; furthermore, neurological toxicity always reversed completely after end of treatment. No long-term toxicity was assessed during the follow-up period, even in patients later subjected to transplant consolidation.

BV induces clinical responses quite rapidly, i.e. within the first 4 cycles in most responders, thus permitting the timely application of the transplantation phase. Furthermore, BV displays a favorable toxicity profile, without overlapping toxicities with most of the agents employed in high-dose conditioning regimens. For patients ineligible for transplant or for who transplant failed, BV may represent a feasible effective therapeutic option in everyday clinical practice.