Efficacy of the anti-CD22 recombinant immunotoxin BL22 in chemotherapy-resistant hairy-cell leukemia

BACKGROUND

Hairy-cell leukemia that is resistant to treatment with purine analogues, including cladribine, has a poor prognosis. We tested the safety and efficacy of an immunotoxin directed against a surface antigen that is strongly expressed by leukemic hairy cells.

METHODS

RFB4(dsFv)-PE38 (BL22), a recombinant immunotoxin containing an anti-CD22 variable domain (Fv) fused to truncated pseudomonas exotoxin, was administered in a dose-escalation trial by intravenous infusion every other day for a total of three doses.

RESULTS

Of 16 patients who were resistant to cladribine, 11 had a complete remission and 2 had a partial remission with BL22. The three patients who did not have a response received low doses of BL22 or had preexisting toxin-neutralizing antibodies. Of the 11 patients in complete remission, 2 had minimal residual disease in the bone marrow or blood. During a median follow-up of 16 months (range, 10 to 23), 3 of the 11 patients who had a complete response relapsed and were retreated; all of these patients had a second complete remission. In 2 of the 16 patients, a serious but completely reversible hemolytic-uremic syndrome developed during the second cycle of treatment with BL22. Common toxic effects included transient hypoalbuminemia and elevated aminotransferase levels.

CONCLUSIONS

BL22 can induce complete remissions in patients with hairy-cell leukemia that is resistant to treatment with purine analogues.

Ketamine-Assisted and Culturally Attuned Trauma Informed Psychotherapy as Adjunct to Traditional Indigenous Healing: Effecting Cultural Collaboration in Canadian Mental Health Care

Ketamine therapy with culturally attuned trauma-informed psychotherapy in a collaborative cross-cultural partnership may provide a critical step in the operationalization and optimization of treatment effectiveness in diverse populations and may provide a foundation for an improved quality of life for Indigenous people. Decolonizing Indigenous health and wellbeing is long overdue, requiring an equal partnership between government and Indigenous communities, built upon an aboriginal culture holistic foundation of balance of mind, body, social and spiritual realms, and within the context of historical and lived experiences of colonialism. Culturally attuned trauma-informed psychotherapy paired with ketamine-a fast-acting antidepressant that typically takes effect within 4 hours, even in cases of acute suicidality-may be uniquely qualified to integrate into an Indigenous based health system, since ketamine's therapeutic effects engage multiple neuropsychological, physiological, biological, and behavioral systems damaged by intergenerational complex developmental trauma. Ketamine holds the potential to serve as a core treatment modality around which culturally engaged treatment approaches might be organized since its brief alteration of normal waking consciousness is already a familiar and intrinsic element of healing culture in many Indigenous societies. There is great need and desire in Indigenous communities for respectful and sacred partnership in fostering more effective mental health outcomes and improved quality of life.