Enhanced Efficacy from Gene Therapy in Pompe Disease Using Coreceptor Blockade

Abstract

Enzyme replacement therapy (ERT) is the standard-of-care treatment of Pompe disease, a lysosomal storage disorder caused by deficiency of acid a-glucosidase (GAA). One limitation of ERT with recombinant human (rh) GAA is antibody formation against GAA. Similarly, in adeno-associated virus (AAV) vector-mediated gene transfer for Pompe disease, development of antibodies against the GAA transgene product and the AAV vector prevents therapeutic efficacy and vector readministration, respectively. Here a nondepleting anti-CD4 monoclonal antibody (mAb) was administrated intravenously prior to administration of an AAV2/9 vector encoding GAA to suppress anti-GAA responses, leading to a substantial reduction of anti-GAA immunoglobulins, including IgG1, IgG2a, IgG2b, IgG2c, and IgG3. Transduction efficiency in liver with a subsequent AAV2/8 vector was massively improved by the administration of anti-CD4 mAb with the initial AAV2/9 vector, indicating a spread of benefit derived from control of the immune response to the first AAV2/9 vector. Anti-CD4 mAb along with AAV2/9-CBhGAApA significantly increased GAA activity in heart and skeletal muscles along with a significant reduction of glycogen accumulation. Taken together, these data demonstrated that the addition of nondepleting anti-CD4 mAb with gene therapy controls humoral immune responses to both vector and transgene, resulting in clear therapeutic benefit in mice with Pompe disease.

Synergistic Efficacy from Gene Therapy with Coreceptor Blockade and a β2-Agonist in Murine Pompe Disease

“…The formation of HSAT blocked the uptake of GAA and provoked fatal hypersensitivity reactions in GAA-KO mice with Pompe disease. 20 Although Nayak and colleagues demonstrated that immune reactions were mediated by a helper T cell type 2 response associated with high-titer IgG1 during ERT, 24 we observed alterations in many subclasses of immunoglobulins, implying a more complex response to AAV vector-mediated GAA expression in GAA-KO mice, 8 Therefore, we have developed coreceptor blockade to eliminate CD4 + T lymphocyte help, and combined this immune tolerance induction with b 2 -agonists to enhance CI-MPRmediated uptake of GAA during gene therapy in Pompe disease. Comparison of biochemical correction after immune tolerance induction with anti-CD4 mAb or liver-specific expression of GAA.…”

“…Induction of immune tolerance was achieved by two different approaches: one approach was focused on the suppression of immune responses through liver-specific expression of GAA 25 and the second acted through blockade of helper T lymphocyte activation with anti-CD4 mAb. 8 At present the need for the induction of immune tolerance is greatest for patients with infantile-onset Pompe disease. In the meantime, the need to induce CI-MPR expression for improvement of GAA uptake in skeletal muscle is greatest for patients with lateonset Pompe disease.…”

“…1), which was similar to the effect of anti-CD4 mAb accompanied by ubiquitous expression of GAA. 8 Thus, the prevention of anti-GAA formation by any method might enhance the efficacy of GAA activity in heart and skeletal muscles, regardless of enzyme sources, either transgene-mediated from gene therapy or from ERT. Multiple approaches for the induction of immune tolerance to a therapeutic protein (human factor IX) have been demonstrated in models for hemophilia, each of which might be adapted to the treatment of Pompe disease, including (1) liverspecific expression of therapeutic genes, 29,30 (2) neonatal exposure to the protein, 31,32 (3) expression of the therapeutic gene in precursor forms of immunologic cells 33 or in tolerogenic B cells, 34 or (4) blockade of coreceptors.…”

“…A single administration of a nondepleting anti-CD4 monoclonal antibody (mAb) before administration of an AAV2/9 vector encoding GAA significantly reduced formation of anti-GAA IgGs, including IgG1, IgG2a, IgG2b, IgG2c, and IgG3. 8 Anti-CD4 mAb along with a vector containing a constitutive promoter, AAV2/9-CBhGAApA, significantly increased GAA activity in muscle, resulting in a significant reduction of glycogen accumulation in the heart and to a lesser extent in skeletal muscle.…”

“…A single injection of anti-CD4 mAb blocked anti-GAA antibody formation, which was provoked by ubiquitous GAA expression with an AAV vector in GAA-KO mice. 8 Simultaneous clenbuterol administration could induce CI-MPR expression in striated muscle. 13 The AAV vector containing a muscle-specific promoter, AAV2/8-MHCK7hGAApA, expressed GAA in both cardiac and skeletal muscle.…”