Adoptive Immunotherapy Using Zoledronate-Activated gd T LAK Cells to Patients with Multiple Myeloma: A Pilot Study.

To evaluate the potential antitumor activity of zoledronate-activated gd T cells in vivo, we initiated a pilot study involving administration of zoledronate-activated gd T LAK cells to patients with multiple myeloma. Subjects (n=4) received four intravenous infusions, at two week intervals, of zoledronate-activated gd T LAK cells generated from culture of peripheral blood mononuclear cells in the presence of zoledronate and IL-2. The patient receiving the highest numbers of gd T LAK cells (patient 02) received a median of 3.86 × 10⁸ zoledronate-activated gd T LAK cells. The other patients received a median of 4.0 × 10⁷ zoledronate-activated gdT LAK cells. Immunological monitoring included immunophenotyping of PB by flow cytometry to determine relative numbers and with the use of full blood cell counts, absolute numbers of Vg9gd T cells, Vg9gd T cell subsets and T cell subsets (CD3+CD4+, CD3+CD8+ or CD3+CD56+). Bone marrow gd T cell numbers, including subsets, were assessed before and 4 weeks after the final treatment. In all patients the absolute and relative numbers of PB T cells and T cell subsets changed minimally during and up to 4 weeks after the treatment period. The percentage of Vg9gd T cells in PBMCs and absolute numbers of Vg9gd T cells in PB increased in one out of 4 patients, patient 02 in whom the largest number of gd T cells were administered. Of potential interest, this was associated with a 30% decrease in M protein levels (IgA) and decreased serum β2-MG following therapy. The other three patients, administered lower numbers of gd T cells, had no change in PB levels of gd T cells and no change in M protein levels, although serumβ2-MG levels fell in 2 out of the 3 cases. To further evaluate the potential for large number of gd T cells to induce immunological changes in the recipients, we focused on the immunological outcomes in the recipient of the highest gd T cell dose (patient 02). The percentage of TEM gd T cells in total Vg9gd T cells and absolute numbers of TEM gd T cells in PB increased during the treatment and remained high in comparison to baseline levels for 4 week after treatment. In parallel, numbers of T naive gd T cells decreased during the treatment and remained below base line levels at 4 weeks after treatment. Interestingly, the increased percentage of TEM gd T cells on day 1 after the final treatment (82.8%) persisted for a further 4 weeks (82.5%), but returned almost to base line levels by 10 weeks after the final treatment (11.3%). In vitro re-stimulation of PBMC with zoledoronate in this case produced higher production of IFNg by the PBMCs than the other 3 cases evaluated. The percentages of Vg9gd T cells and TEM gd T cells in bone marrow increased in 2 out of 4 patients 4 weeks after the final treatment. In parallel, the percentages of T naive gd T cells decreased. Minor systemic side effects, including fever, malaise and lethargy were noted but there were no serious treatment related adverse events. In summary, administration of gd T LAK cells is well tolerated and may modulate PB and BM Vg9gd T cells when sufficient cells are administered. The increased percentage of TEM Vg9gd T cells in PB and BM may induce antitumor activity in patients with multiple myeloma.