The following article features coverage from the 2021 Annual Meeting of the Society of Hematologic Oncology (SOHO). Click here to read more of Hematology Advisor‘s conference coverage.

Longer follow up of patients in a phase 2 study demonstrated durable responses to loncastuximab tesirine (Lonca; formerly ADCT-402) in heavily pretreated patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), with no new safety signals.

The updated results were presented by Brad Kahl, MD, of Washington University, St. Louis, MI, at the Annual Meeting of the Society of the Hematologic Oncology (SOHO).

LOTIS-2 (ClinicalTrials.gov Identifier: NCT03589469), is an ongoing multicenter, open-label, single-arm phase 2 study evaluating the efficacy and safety of Lonca, a humanized anti-CD19 antibody conjugated to a pyrrolobenzodiazepine dimer toxin, in adult patients with R/R DLBCL and who have relapsed after ≥2 prior systemic treatments.


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Participants received ≥1 dose Lonca (150 µg/kg every 3 weeks [Q3W] for 2 cycles, then 75 µg/kg Q3W). The primary efficacy endpoint is overall response rate (ORR). Secondary efficacy endpoints include duration of response (DoR), progression-free survival (PFS), and overall survival (OS). Safety analyses include treatment-emergent adverse events (TEAEs). The planned follow-up period is Q12W for ≤3 years after the end of treatment. The updated results included ≥17 months of follow up since patients’ first dose.

A total of 145 patients with a median age of 66 years (range 23-94) received ≥1 Lonca dose (mean, 4.6 cycles; range, 1-22). Patients had received a median of 3 prior therapies (range, 2-7).

At data cut-off (March 1, 2021, ≥17 months since first dose), the ORR was 48.3%, with a complete response (CR) rate of 24.8% and partial response (PR) rate of 23.4%. The median DoR was 13.4 months for patients who responded (CR or PR; n=70), 5.7 months for patients with PR and not reached for patients with CR. The median PFS was 4.9 months (95% CI, 2.9-8.3) and, the median OS was 9.5 months (95% CI, 6.9-11.5).

Following Lonca treatment, 16 patients received CD19-directed chimeric antigen receptor T-cell therapy with an investigator-assessed ORR of 43.8%, and 11 patients underwent SCT as consolidation after responding to Lonca.

Among patients with CR, 44.4% remained in CR with no further treatment, while 36.1% experienced progressive disease or death. When excluding 10 patients who were censored due to SCT, these rates were 61.5% and 34.6%, respectively.

Grade ≥3 TEAEs occurred in 73.8% patients; the most common (≥10%) were neutropenia (26.2%), thrombocytopenia (17.9%), increased GGT (17.2%), and anemia (10.3%). Serious TEAEs occurred in 39.3% of patients, and TEAEs with a fatal outcome in 5.5% (n=8) of patients. TEAEs leading to treatment discontinuation and dose delays occurred in 18.6% and 42.8% of patients, respectively.

Efficacy and safety continue to be monitored.

Disclosure: This research was supported by ADC Therapeutics SA. Please see the original reference for a full list of disclosures.

Read more of Hematology Advisor’s coverage of SOHO 2021 by visiting the conference page.

Reference

Kahl BS, Hamadani M, Caimi PF, et al. LOTIS-2 follow-up analysis: Updated results from a phase 2 study of loncastuximab tesirine (Lonca) in relapsed or refractory diffuse large B-Cell lymphoma. Paper presented at: Annual Meeting of the Society of Hematologic Oncology (SOHO); September 8-11, 2021. Abstract ABCL-022.