Effect of aminobisphosphonates and statins on circulating Vgamma9Vdelta2-T cells

Vy9Vd2-T cells are lymphocytes that play an important role in antitumor
immunity. They can be activated by phosphoantigens, which has recently been
shown to result in their acquisition of antigen presenting call properties.
Aminobisphosphonates are administered 3-4 weekly to patients with bone
metastases from various malignancies in order to reduce the number of skeletal
events. By inhibiting mevalonate metabolism (resulting in the accumulation of
endogenous phosphoantigens) aminobisphosphonates can also result in the
activation of Vy9Vd2-T cells. Since preclinical data indicate that statins
inhibit endogenous phosphoantigen accumulation and Vy9Vd2-T cell activation,
one can envision that statins can similarly inhibit the
aminobisphosphonate-induced activation of Vy9Vd2-T cells in vivo. In this study
the effects of aminobisphosphonate treatment and the inhibitory effects of the
simultaneous use of statins on Vy9Vd2-T cells will be evaluated. This is
relevant as data from e.g. breast cancer and prostate cancer patients indicate
that aminobisphosphonates, via the activation of Vy9Vd2-T cells, can induce
clinically relevant antitumor responses. Inhibition of this activation by the
simultaneous use of statins could be detrimental in such circumstances.

To study (in patients who have an indication for treatment with an intravenous
aminobisphosponate because of bone metastases of a malignant tumor) the effects
of aminobisphophonate treatment on the phenotype and function on circulating
Vy9Vd2-T cells and to determine whether these effects are inhibited by
simultaneous treatment with statins.

A total of 40 patients will be entered in this study. Half of the patients will
receive standard intravenous treatment with aminobsiphosphonates, the other
half will be additionally be treated with a statin. Patients already receiving
statin treatment will continue this treatment, other patients will be asked
whether they are willing to be treated with a statin for a maximum of 5 weeks.
Consenting patients will be randomized to receive i.v. aminobisphosponates plus
or minus simvastatin 40 mg once daily. Simvastatin will be started one week
prior to the first administration of aminobisphosphonates and continued for a
maximum of 5 weeks.

In each patient 20 ml peripheral blood will be drawn (t=0, t=24 hr, t=1 week,
t=3-4 weken (prior to the 2nd aminobisphosphonate administration). In addition,
patients will be requested to measure their temperature thrice daily during the
2 days following the first aminobisphosponate administration. This, because a
relation between the occurrence of a febrile response upon aminobisphosponate
administration and an activation and expansion of Vy9Vd2-T cells has been
suggested.

Peripheral blood mononuclear cells will be isolated from the drawn peripheral
blood. Using intra- and extracellular flowcytometry Vy9Vd2-T cells will be
characterized phenotypically (APC markers: CD1d, CD40, CD80, CD83, CD86,
HLA-DR; activation/memory markers: CD25, CD27, CD45RA, CD45RO, CCR7) and
functionally (IFN-*, TNF-*, granzyme B). In addition, the frequency of CD3+,
CD4+, CD8+ T cells, NK cells, B cells, iNKT cells, CD4+CD25+ regulatory T
cells, and circulating dendritic cells will be assessed.

Treatment with simvastatin in patients with malignant bone metastases with an
indication for treatment with aminobisphosphonates.

This study exerts a minimal burden on patients (blood withdrawel on 4
occasions, thrice daily temperature assessment for 2 days). Part of the
patients will be treated with simvastatin (1 tablet daily) for 4-5 weeks.
Simvastatin has been administered to enormous amounts of patients facing
hypercholesterolemia world-wide. From this clinical experience it is known that
it can be safely administered to patients with a relatively small chance of
(serious) side-effects.