Therapeutic use of OKT3 monoclonal antibody for acute renal allograft rejection

Teplizumab in Type 1 Diabetes Mellitus: An Updated Review

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune condition characterized by the irreversible destruction of the β cells of the pancreas, which leads to a lifelong dependency on exogenous insulin. Despite the advancements in insulin delivery methods, the suboptimal outcomes of these methods have triggered the search for therapies that may prevent or reverse the disease. Given the autoimmune aetiology of T1DM, therapies counteracting the immune-mediated destruction of the β-cells are the obvious target. Although several treatment strategies have been attempted to target cellular, humoral and innate immunity, very few have had a clinically meaningful impact. Of all the available immunomodulatory agents, cluster of differentiation (CD) 3 antibodies have exhibited the most promising preclinical and clinical results. Muromonab-CD3, which also happened to be a murine CD3 antibody, was the first monoclonal antibody approved for clinical use and was primarily indicated for graft rejection. The adverse effects associated with muromonab-CD3 led to its withdrawal. Teplizumab, a newer CD3 antibody, has a better side-effect profile because of its humanized nature and non-Fc-receptor-binding domain. In November 2022, teplizumab became the first immunomodulatory agent to be licensed by the US Food and Drug Administration for delaying the onset of T1DM in high-risk adults and children over 8 years old. The mechanism seems to be enhancing regulatory T-cell activity and promoting immune tolerance. This article reviews the mechanism of action and the clinical trials of teplizumab in individuals with T1DM or at risk of developing the disease.

Cell-penetrating porcine single-chain antibodies (transbodies) against nonstructural protein 1β (NSP1β) of porcine reproductive and respiratory syndrome virus inhibit virus replication

Porcine reproductive and respiratory syndrome virus (PRRSV) causes porcine reproductive and respiratory syndrome (PRRS) worldwide, especially in domestic pigs, with an enormous economic impact, estimated at $664 million in losses every year to the pig industry. Current vaccines confer limited protection, and no direct-acting anti-PRRS treatment is available. Non-structural protein (NSP) 1β, a cysteine-like protease (CLPro) of PRRSV plays an essential role in viral polyprotein processing, subgenomic RNA synthesis, and evasion of host innate immunity. Therefore, agents that interfere with the bioactivity of NSP1β would be expected to inhibit virus replication. In this study, a porcine single-chain antibody (scFv)-phage display library was constructed and used as a tool for production of NSP1β-specific porcine scFvs (pscFvs). The pscFvs to NSP1β were linked to a cell-penetrating peptide to form cell-penetrating pscFvs (transbodies), which could be internalized and inhibit PRRSV replication in infected cells. A computer simulation indicated that the effective pscFvs used several residues in multiple complementarity determining regions (CDRs) to interact with multiple residues in the CLPro and C-terminal motifs, which might explain the mechanism of pscFv-mediated inhibition of virus replication. Although experiments are needed to determine the antiviral mechanism of the transbodies, the current data indicate that transbodies can potentially be applied for treatment and prevention of PRRSV infection.

Generation and Next-Generation Sequencing-Based Characterization of a Large Human Combinatorial Antibody Library

Antibody phage display is a key technology for the discovery and development of target-specific monoclonal antibodies (mAbs) for use in research, diagnostics, and therapy. The construction of a high-quality antibody library, with larger and more diverse antibody repertoires, is essential for the successful development of phage display-derived mAbs. In this study, a large human combinatorial single-chain variable fragment library (1.5 × 10¹¹ colonies) was constructed from Epstein-Barr virus-infected human peripheral blood mononuclear cells stimulated with a combination of two of the activators of human B cells, the Toll-like receptor 7/8 agonist R848 and interleukin-2. Next-generation sequencing analysis with approximately 1.9 × 10⁶ and 2.7 × 10⁶ full-length sequences of heavy chain variable (VH) and κ light chain variable (Vκ) domains, respectively, revealed that the library consists of unique VH (approximately 94%) and Vκ (approximately 91%) sequences with greater diversity than germline sequences. Lastly, multiple unique mAbs with high affinity and broad cross-species reactivity could be isolated from the library against two therapeutically relevant target antigens, validating the library quality. These findings suggest that the novel antibody library we have developed may be useful for the rapid development of target-specific phage display-derived recombinant human mAbs for use in therapeutic and diagnostic applications.

[Monoclonal antibodies for anti-infective therapy]

Ein Jahrhundert lang wurde die Serumtherapie von Seren tierischen Ursprungs und Hyperimmunglobulinen dominiert. Obwohl seit Ende der Achtzigerjahre des letzten Jahrhunderts zahlreiche monoklonale Antikörper (MAB) insbesondere zur Behandlung von immunologischen und onkologischen Erkrankungen entwickelt wurden, sollte es noch 20 Jahre bis zur Zulassung des ersten antiinfektiven MAB in der Europäischen Union dauern. In den folgenden 2 Dekaden kamen nur 2 weitere antiinfektive MAB hinzu. Interessanterweise werden zurzeit zur Bekämpfung der COVID-19-Pandemie zahlreiche MAB, die insbesondere in immunologischer Indikation zugelassen sind, zur Behandlung der Folgen der SARS-CoV-2-Infektion, wie Pneumonie oder Hyperimmunreaktion, eingesetzt.

Im Folgenden werden die zugelassenen monoklonalen Antikörper zur Behandlung von Infektionskrankheiten vorgestellt. Darüber hinaus wird eine Übersicht über die aktuellen Entwicklungen, insbesondere bei der Therapie der SARS-CoV-2-Infektion, gegeben.

Monoclonal antibodies as anti-infective products: a promising future?

BACKGROUND

The paucity of licensed monoclonal antibodies (mAbs) in the infectious diseases arena strongly contrasts with the ready availability of these therapeutics for use in other conditions.

AIMS

This narrative review aims to assess the potential of monoclonal antibody-based interventions for infectious diseases.

SOURCES

A review of the literature via the Medline database was performed and complemented by published official documents on licensed anti-infective mAbs. In addition, ongoing trials were identified through a search of the clinical trial registration platform ClinicalTrials.gov.

CONTENT

We identified the few infections for which mAbs have been added to the therapeutic armamentarium and stressed their potential in representing a readily available protection tool against biothreats and newly emerging and reemerging infectious agents. In reviewing the historical context and main features of mAbs, we assert a potentially wider applicability and cite relevant examples of ongoing therapeutic developments. Factors hindering successful introduction of mAbs on a larger scale are outlined and thoughts are offered on how to possibly address some of these limitations.

IMPLICATIONS

mAbs may represent important tools in treating or preventing infections occurring with reasonably sufficient prevalence to justify demand and for which existing alternatives are not deemed fully adequate. Future initiatives need to address the prohibitive costs encountered in the development process. The feasibility of more large-scale administration of alternative modalities merits further exploration. In order to ensure optimal prospect of regulatory success, an early dialogue with competent authorities is encouraged.

Antibody Agents in Solid Organ Transplantation

Antibody agents play an important role in the pharmacotherapy of solid organ transplantation. These agents can be either monoclonal or polyclonal, derived from an animal source or genetically engineered utilizing human antibody sequences. This reviewpresents basic pharmacology and therapeutic issues related to the antibody preparations utilized in transplantation including equine and rabbit antithymocyte globulins, muromonab-CD3, daclizumab, and basiliximab. The parameters covered for these agents include mechanism of action, pharmacokinetics, pharmacodynamic monitoring strategies, clinical dosing, adverse effects, and clinical trials. The brief overviewof current clinical data related to these agents focuses on kidney transplantation. The use of these very powerful agents in different patient populations needs to be individualized based on certain risks and these data are presented to help in the decision-making process, especially for renal allograft recipients.

A prospective, double-blind, randomized study of high-versus low-dose OKT3 induction immunosuppression in cadaveric renal transplantation

We undertook a prospective, double-blind study of high-(5-mg) versus low-(2-mg) dose OKT3 for induction immunosuppression (12 days) in cadaveric renal allograft transplantation. Maintenance immunosuppression was identical in both groups and consisted of azathioprine and prednisone initially, with cyclosporine beginning on the 5th postoperative day. Twenty-six patients were randomized. The groups were similar in terms of age, kidney ischemia time, peak PRA, and latest PRA. There were more diabetics and women in the high-dose group. Patient survival at 12 months was 100% in both groups. Graft survival at 12 months was 92% and 100% in the high- and low-dose groups, respectively. Infections were mostly minor and equal in frequency in the two groups. All patients receiving high- or low-dose OKT3 had manifestations of the cytokine release syndrome; these were delayed in onset in the low-dose group. Eleven patients (85%) in each group produced anti-OKT3 antibodies. Lymphocyte depletion after 1 day was major (> 98%) and identical in both groups. CD3 antigens were removed more slowly in the low-dose group but eventually at equal rates in both groups. Cost was significantly lower in the low-dose group. We conclude that while both doses of OKT3 were effective and safe for induction immunosuppression, it may be prudent to use a lower dose of OKT3 for induction immunosuppression because of its potential to reduce cytokine-mediated effects and to avoid the complications of overimmunosuppression and because of the lower costs associated with it.

Evaluation of OKT3 monoclonal antibody and anti-thymocyte globulin in the treatment of steroid-resistant acute allograft rejection in pediatric renal transplants

We reviewed the effectiveness of Muromonab-CD3 (OKT3) and anti-thymocyte globulin (ATG) in the treatment of corticosteroid-resistant acute renal allograft rejection in 49 transplanted children. Reversal of rejection was successful in 22 of 23 patients (96%) treated with OKT3 and 21 of 26 (81%) treated with ATG (P = NS). Re-rejection episodes occurred within 1 month of cessation of therapy in 9 of 22 patients treated with OKT3 but only in 2 of 21 who received ATG (P < 0.05). In the patients with re-rejection, 7 of the 9 patients originally given OKT3 and 1 of the 2 who received ATG responded to a repeat course of high-dose corticosteroids; thus, at 1 month post treatment, the incidence of graft loss due to initial rejection or re-rejection was 13% for the OKT3 and 23% for the ATG group (P = NS). Graft survival was similar at 6 months: 82% for OKT3- and 73% for ATG-treated patients (P = NS); 100% patient survival was noted in both groups. Mean calculated creatinine clearance prior to, during, and at 1 and 6 months post rejection was similar in the OKT3- and ATG-treated groups. Neutropenia and thrombocytopenia occurred more frequently in the ATG group, but there was no significant difference in infectious complications. Two patients developed high (> or = 1:1,000) OKT3 antibody titers. In our experience, children with corticosteroid-resistant acute renal allograft rejection treated with OKT3 and ATG had similar allograft survival and level of renal function at 1 and 6 months, and number of infectious complications post therapy.

Anti-OKT3 response following prophylactic treatment in paediatric kidney transplant recipients

The anti-OKT3 response was studied in 40 paediatric kidney transplant recipients receiving OTK3 as a prophylactic treatment in association with azathioprine and prednisone. Only 1 patient experienced a reversible acute rejection episode while receiving OKT3. OKT3 induced a rapid disappearance of CD3+ cells, but significant proportions of CD3+ cells reappeared before the end of the treatment in 14 patients. Wide variations in circulating OKT3 levels were observed and in only 50% of patients could stable circulating OKT3 levels be detected until discontinuation of treatment. Anti-OKT3 antibodies detected by the enzyme-linked immunosorbent assay (ELISA) (anti-idiotypic and anti-isotypic antibodies) developed in 91% of patients. Anti-idiotypic antibodies detected by the immunofluorescence inhibition test were found in the sera of 71% of patients, always when high titres of anti-OKT3 antibodies were detected by ELISA. As it has recently been shown that anti-idiotypic antibodies are associated with failure of subsequent OKT3 treatment, we conclude that OKT3 should be restricted to steroid-resistant rejection crises in paediatric patients.

Monoclonal antibodies in renal transplantation: a review

OKT3 is the first anti-CD3 monoclonal antibody available for treatment in humans. Over the last few years it has proven to be a very powerful immunosuppressive agent in renal transplantation. Clinical studies have shown that OKT3 is superior to high-dose steroids as first-line treatment for acute renal allograft rejection. Furthermore, it is comparable to antithymocyte globulin (ATG) in treating steroid-resistant rejection and is also effective as rescue treatment in ATG- and antilymphocyte globulin-(ALG-) resistant rejection. Despite its excellent rejection-reversal rate, OKT3 treatment is followed by a substantial percentage of re-rejections, most of which respond well to steroids. In the early post-transplantation period, a prophylactic course of OKT3 is very effective in preventing acute rejections, and in this respect it is probably equivalent to ATG. Indirect evidence exists that a prophylactic course of OKT3 may be beneficial in immunologically high-risk patients and in patients with delayed graft function. However, more clinical studies are required to answer the question whether OKT3 should be given as induction treatment, as first-line treatment, or as rescue treatment. To answer this question, the side effects of OKT3 should also be taken into account. First-dose-related side effects, although frequent and disturbing, are usually transient and seldom life-threatening, provided overhydration has been corrected and steroids have been given before the first administration. These side effects are attributed to the release of cytokines as a result of T-cell activation or lysis. After exposure of patients to OKT3 an increased incidence of infections and malignancies has been reported. However, it is not yet clear whether this is due to OKT3 as such, or whether it merely reflects the total burden of immunosuppression. Xeno-sensitization represents an important limitation to OKT3 treatment, although a second or third course can still be effective in patients with low antibody titers. The precise immunosuppressive mechanism of anti-CD3 monoclonal antibodies is yet unknown. Monitoring of patients treated with OKT3 revealed CD3 and/or T-cell antigen receptor depletion and immunological incompetence of remaining T cells. More clinical data are required to establish the correct dose and duration of OKT3 treatment. In conclusion, OKT3 is a powerful immunosuppressive agent but its real value in renal transplantation remains to be determined. A practical approach may be to reserve it for the treatment of steroid-resistant rejections.(ABSTRACT TRUNCATED AT 400 WORDS)

Prophylactic use of OKT3 in liver transplantation. A review

Liver rejection in the era of cyclosporine-based immunosuppression is approximately 60-70%. Approximately 15-25% of liver transplant patients will require hemodialysis following transplantation. These facts argue for a potent, less nephrotoxic immunosuppressive regimen, especially during the period of vulnerability to these events. Prophylactic use of OKT3 has been suggested as a means to decrease the need for hemodialysis while maintaining potent immunosuppression. The goal of this review is to examine potential benefits and pitfalls of this regimen. A lack of documentation of long-term patient and graft survival, the potential susceptibility to infectious complications, development of sensitization, and the cost must be weighed against the decreased need for hemodialysis and the control of early rejection episodes.

Cardiovascular collapse following orthoclone OKT3 administration: a case report

Orthoclone OKT3 has been described to have significant adverse effects on the cardiovascular system, including pulmonary edema, angina, dysrhythmias, hypertension, and hypotension, usually following the first or second doses of the drug. We describe a case of cardiopulmonary arrest in a patient 1 minute after the initial injection of OKT3. Two subsequent doses were successfully administered with the guidance of hemodynamic monitoring, which showed profound, immediate effects of OKT3 on the cardiovascular system. Potential mechanisms of these effects are discussed.

The role of OKT3 in clinical transplantation

OKT3 is a murine monoclonal anti-T cell antibody that is directed to CD3, a five-chain molecular complex found in association with the T cell receptor for antigen. OKT3 was the first monoclonal antibody to be used in organ transplantation and during the past 10 years there has been extensive experience of its use both for preventing and treating rejection in organ transplantation. OKT3 blocks T cell function by modulating CD3 and the T cell receptor from the T cell surface. A reaction to OKT3 results from cytokines released when OKT3 first reacts with T cells. This reaction is generally mild but can be severe. First rejections following kidney transplantation are reversed in approximately 95% of cases. Steroid-resistant rejections are also susceptible to OKT3 but in only approximately 75% of cases. When used for prophylaxis, OKT3 completely blocks rejection in 95% of patients and significantly delays the onset of rejection in those who do reject. Antibodies to OKT3 are produced in approximately 75% of patients receiving it. However, seldom are the antibodies to OKT3 present in high titer and only in those cases is successful re-use of OKT3 prevented. As is the case with all potent immunosuppressive drugs, the use of OKT3 is associated with increased viral, specifically cytomegalovirus, infections. However, it appears that reduction of concomitant immunosuppression decreases the incidence of severe infections. Unquestionably, OKT3 has been a useful addition to the immunosuppression used for organ transplantation. In addition, its use has stimulated research on other monoclonal antibodies for use in organ transplantation.

Prevention of acute graft rejection by the prostaglandin E1 analogue misoprostol in renal-transplant recipients treated with cyclosporine and prednisone

Prostaglandins of the E series have been shown to have immunosuppressive properties. To study the effects of the prostaglandin E1 analogue misoprostol on renal function and graft rejection after transplantation, we conducted a randomized, double-blind, placebo-controlled trial in 77 renal-allograft recipients. The subjects received misoprostol (200 micrograms four times daily by mouth; n = 38) or placebo (n = 39) for the first 12 weeks after transplantation, in addition to standard immunosuppression with cyclosporine and prednisone. They were then observed for an additional four weeks after the drug or placebo was discontinued. Treatment with misoprostol was associated with a significant improvement in renal function as judged by the mean (+/- SEM) serum creatinine concentration (128 +/- 7 vs. 158 +/- 11 mumol per liter after 12 weeks; P = 0.03) and creatinine clearance (84 +/- 6 vs. 69 +/- 5 ml per minute per 1.73 m2 of body-surface area; P = 0.05). There was a significant reduction in the incidence of acute rejection in the group treated with misoprostol as compared with the placebo group (10 of 38 vs. 20 of 39; P = 0.02), and there was less need for rehospitalization after transplantation (4 +/- 1 days with misoprostol vs. 10 +/- 2 days for placebo; P = 0.03). Although blood levels of cyclosporine did not differ significantly between the groups, they tended to be higher in the misoprostol group, as did the incidence of acute nephrotoxicity due to cyclosporine (13 of 38 vs. 8 of 39). Infectious complications tended to be fewer in the misoprostol-treated group (14 of 38 vs. 21 of 39). We conclude that misoprostol improves renal function and safely reduces the incidence of acute rejection in renal-transplant recipients treated concurrently with cyclosporine and prednisone.

Recurrence of acute rejection in the absence of CD3-positive lymphocytes

Allograft rejection is the single largest impediment to successful transplantation. Therapy targeted to lymphocytes has been in practice for many years using polyclonal heteroantisera. These products are generally accepted as being useful for the prevention and treatment of rejection; however, there have been problems with specificity, lot to lot variability, and supply. Therapy with monoclonal antibodies such as OKT3 may circumvent these problems and may allow for refined specificity. OKT3 has been shown to be highly effective at reversing acute renal allograft rejection. The few treatment failures were attributed to anti-mouse antibodies eliminating the OKT3, or to delay of therapy to such a late stage that rejection was irreversible. We present two cases which demonstrate successful reversal of acute rejection in cadaveric renal transplants by OKT3. The reversal was transient, however, in both cases, as both patients experienced recurrence of rejection while still receiving the monoclonal antibody. This occurred despite the absence of CD3-positive cells in the peripheral blood, and the presence of excess OKT3 in the serum. This implies that CD3-negative lymphocytes may under certain circumstances contribute to the rejection phenomenon.

Early use of OKT3 monoclonal antibody in renal transplantation to prevent rejection

OKT3 monoclonal anti-T cell antibody was used during the first 2 weeks following cadaveric renal transplantation to prevent rejection. When compared with a control group receiving triple immunosuppression with cyclosporine, azathioprine, and prednisone, the OKT3, azathioprine, and prednisone group had significantly fewer acute rejections during the first month (6% v 50%; P less than 0.01), and the mean time of onset of the first rejection was significantly delayed (day 47 v day 8; P less than 0.01) in the OKT3 prophylaxis group. OKT3 was administered intraoperatively safely and without complications on the day of transplantation. The well-reported first dose reaction to OKT3 was similar in these patients when compared with patients receiving OKT3 for treatment of rejection. Anti-OKT3 antibody development occurred in half of the patients receiving OKT3, and did not prevent the subsequent use of OKT3 in these patients, whose rejections following OKT3 prophylaxis were steroid reversible. There were no deaths among the patients receiving prophylactic OKT3, and during a 15-month follow-up, only three of 34 kidneys were lost for any reason. In addition to its use for primary and steroid-resistant rejection, OKT3 may be useful early after transplantation to prevent rejection.

The use of OKT3 in cadaveric renal transplantation for rejection that is unresponsive to conventional anti-rejection therapy

Thirty-one recipients of cadaver kidney transplants were given OKT3 monoclonal anti-T cell antibody for rejection treatment after conventional therapy had failed. Seventy-four percent of steroid or steroid and antithymocyte globulin (ATG) resistant rejections reversed with a standard course of OKT3. Rejections reversed in 85% of 26 patients treated within 90 days of transplantation. Late rejections treated more than 90 days after transplantation were poorly responsive to OKT3 and graft survival for this group of five patients was poor (20%). However, for those patients treated with OKT3 for early resistant rejection, actuarial 4-year graft survival was 66%. Actuarial 4-year patient survival was 97%, and the incidence of serious infection was low. Acute rejections in cadaver transplantation are common and a small percentage of rejections are resistant to steroids and ATG. OKT3 has proven to be useful for reversing these resistant rejections without causing significant morbidity from infection or death.