Development and conduct of allogeneic stem cell transplant and autologous stem cell gene therapy for inherited immune deficiencies

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications & trials

Abstract

The first part of this project involves the development of conditioning regimens for allogeneic transplantation of patients with primary immunodeficiencies. In 2007 we initiated a clinical protocol using busulfan, Campath and low dose TBI and treated 44 patients with CGD, 39 of whom received an unrelated donor (MUD) graft. The results were published in the Journal of Clinical Immunology. (Parta et al. JCI). Included in this cohort were two patients with the P40 form of CGD demonstrating complete reversal of refractory colitis in this unique subset. In follow up to that study we have opened a new protocol modeling on our previous results using a higher cell dose and post-transplant cyclophosphamide to improve engraftment but mitigate the increased risk of Graft versus Host Disease (GvHD) from the larger graft. We initially enrolled 10 patients with 3 deaths due to progressive pulmonary disease and one patient with graft loss who did not receive post transplant cyclophosphamide. A retrospective evaluation of all transplanted patients suggested that an elevated C reactive protein (CRP) prior to the transplant itself was the one common risk factor and the protocol was thus modified to exclude patients who have an elevated CRP. We have subsequently transplanted 15 more patients (7 in the last 5 months after a hiatus due to COVID) with good outcomes except for one graft loss despite initial engraftment. He remains alive and well. The remainder of the patients have all engrafted with no severe GvHD. We also transplanted two patients as exemptions to the protocol (with elevated CRPs) with one patient expiring due to progression of his underlying infection and the other doing well despite extensive disease and functional quadriplegia prior to transplant. To expand eligibility, in 2014 we opened a protocol using haploidentical donors. The 1st patient had an ongoing infection refractory to all standard therapy involving the heart and is now 5 years out with complete resolution of his infection. (J Clin Immunol. 2015 Oct;35(7):675-80). We enrolled a total of 7 patients on this protocol but saw severe GvHD in the last 3 patients with 2 of the patients succumbing to its' complications but the 3rd patient recovering and now doing well. This protocol is now closed and a new protocol is now open to accrual (19-I-0080). This protocol used both early and late Campath along with busulfan, TBI, and post-transplant cyclophosphamide. The first patient did very well with full engraftment, and no evidence of GvHD. The 2nd patient developed significant GvHD, thus the protocol was modified to change the timing of the Campath. The 3rd patient has done well with this modification and a 4th patient is now undergoing transplant. A protocol for X-linked and JAK-3 SCID (20-I-0080) has also been opened for accrual. No patients have yet been enrolled although one is being evaluated now. We are also working towards developing antibody based conditioning regimens for CGD and SCID patients in order to further reduce regimen toxicity . The SCID study has been approved and the CGD study is going through the regulatory steps. As a member of the Primary Immune Deficiency Treatment Consortium (J Allergy Clin Immunol. 2014 Feb;133(2):335-47) we developed a collaborative protocol (6903) to review the results of transplants done for CGD in North America. We enrolled over 100 transplanted patients and published the results on a subgroup of patients with inflammatory bowel disease (Marsh et al, JCI 2019). We are now in the midst of analyzing the data from the overall study. We have also been involved in a microbiome analysis, (a substudy done in collaboration with Emilia Falcone) with a manuscript now in preparation. We are also finalizing a new CGD related protocol (6908) which will specifically evaluate the autoinflammatory aspects of CGD patients pre and post-transplant. In the laboratory, our post bacs Caroline Kreitzer and Nicole Fama (now Karissa Bever) have worked on developing murine models of engraftment syndrome and graft failure as these both occur with significant frequency in our CGD patients and improved understanding of the pathophysiologies should lead to better prevention and treatment. Utilizing our established murine models of GvHD, they have modified the conditioning regimens to induce graft rejection and/or engraftment syndrome with various cytokines to mimic the inflammatory milieu seen in patients as well as manipulating the graft cell composition to assess any donor graft effects. Although progress has been made in these efforts, there have been delays due to Covid-19. The second part of this project involves the use of genetically modified autologous cells for the treatment of patients with XCGD and other immunodeficiencies. We initiated a clinical trial in 2006 to treat XCGD patients and an underlying infection, protocol 07-I-0017. Based on preclinical data in the rhesus as well as clinical data in a patient, we used busulfan at a dose of 10mg/kg prior to infusion of the genetically modified cells. We treated 3 patients, the results of which were published in Blood. Of the 3 patients the first had persistent levels of detectable oxidase positive cells more than 7 years post gene therapy; however he developed a progressive pulmonary process which despite an attempt at allogeneic transplant, led to his demise in 2016. The 2nd patient treated on this trial appeared to develop an immune reaction against the transduced cells, with rapid clearance of these cells after initially having 5% marking. The 3rd patient was treated for a fungal lung infection and had an initial marking level of 4% with a subsequent decline to 0.03% where it remained stable until he underwent a MUD transplant due to continued infections. He is now more than 5 years out doing well. In 2015 we developed a collaborative study, Protocol 15-I-0008, using a lentiviral vector for XCGD. The 2nd patient on the trial was treated at NIH in 2016, and continues to have marking in the 20-30% range more than 3 years post treatment. The 2nd NIH patient is now over 2 years post transplant with resolution of his underlying pulmonary fungal infection. Our 3rd patient was treated in 2017 and unfortunately developed autoimmune thrombocytopenia, unrelated to the gene therapy, and died of a cerebral hemorrhage. Our most recent patient, treated in 2019, is doing well with more than 70% oxidase cells at his last evaluation with follow up pending to patient ability to travel. A total of 9 patients have been treated at the various sites with 3 patients, including the last patient treated in 2020, having loss of their marking. The results have been published. (Kohn et al. Nature Medicine 2020.) An addendum protocol to treat patients with the same vector but using a modified conditioning regimen has now been IRB approved and the first patient is being treated at UCLA (July 2021) with subsequent patients to be treated at NIH. We are also developing a collaborative study to treat patients with the P47 autosomal recessive form of CGD using a lentiviral vector and will start enrolling patients by early 2022 (delayed due to the Covid-19). Future plans will include incorporating transduction enhancers to improve the efficiency of transduction and reduce the amount of vector needed to treat each patient. We are also planning to involve the use of antibody-based conditioning similar to our allogeneic transplantation. Uimook Choi and Nicole have developed vectors for the P67 and P22 forms of CGD. Finally, Caroline (now Karissa), in collaboration with the laboratory of Mihailis Lionakis, has been developing a CARD 9 lentivector with initial data showing some efficacy in in vitro studies. In vivo mouse studies are pending once adequate vector can be produced.