Clinical development of cell therapies for cancer: The regulators' perspective

Challenges and Lessons Learned in Autologous Chimeric Antigen Receptor T-Cell Therapy Development from a Statistical Perspective

Chimeric antigen receptor (CAR) T-cell therapy is a human gene therapy product where T cells from a patient are genetically modified to enable them to recognize desired target antigen(s) more effectively. In recent years, promising antitumor activity has been seen with autologous CAR T cells. Since 2017, six CAR T-cell therapies for the treatment of hematological malignancies have been approved by the Food and Drug Administration (FDA). Despite the rapid progress of CAR T-cell therapies, considerable statistical challenges still exist for this category of products across all phases of clinical development that need to be addressed. These include (but not limited to) dose finding strategy, implementation of the estimand framework, use of real-world data in contextualizing single-arm CAR T trials, analysis of safety data and long-term follow-up studies. This paper is the first step in summarizing and addressing these statistical hurdles based on the development of the six approved CAR T-cell products.

RE-MIND2: comparative effectiveness of tafasitamab plus lenalidomide versus polatuzumab vedotin/bendamustine/rituximab (pola-BR), CAR-T therapies, and lenalidomide/rituximab (R2) based on real-world data in patients with relapsed/refractory diffuse large B-cell lymphoma

RE-MIND2 (NCT04697160) compared patient outcomes from the L-MIND (NCT02399085) trial of tafasitamab+lenalidomide with those of patients treated with other therapies for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who are autologous stem cell transplant ineligible. We present outcomes data for three pre-specified treatments not assessed in the primary analysis. Data were retrospectively collected from sites in North America, Europe, and the Asia Pacific region. Patients were aged ≥18 years with histologically confirmed DLBCL and received ≥2 systemic therapies for DLBCL (including ≥1 anti-CD20 therapy). Patients enrolled in the observational and L-MIND cohorts were matched using propensity score-based 1:1 nearest-neighbor matching, balanced for six covariates. Tafasitamab+lenalidomide was compared with polatuzumab vedotin+bendamustine+rituximab (pola-BR), rituximab+lenalidomide (R2), and CD19-chimeric antigen receptor T-cell (CAR-T) therapies. The primary endpoint was overall survival (OS). Secondary endpoints included treatment response and progression-free survival. From 200 sites, 3,454 patients were enrolled in the observational cohort. Strictly matched patient pairs consisted of tafasitamab+lenalidomide versus pola-BR (n = 24 pairs), versus R2 (n = 33 pairs), and versus CAR-T therapies (n = 37 pairs). A significant OS benefit was observed with tafasitamab+lenalidomide versus pola-BR (HR: 0.441; p = 0.034) and R2 (HR: 0.435; p = 0.012). Comparable OS was observed in tafasitamab+lenalidomide and CAR-T cohorts (HR: 0.953, p = 0.892). Tafasitamab+lenalidomide appeared to improve survival outcomes versus pola-BR and R2, and comparable outcomes were observed versus CAR-T. Although based on limited patient numbers, these data may help to contextualize emerging therapies for R/R DLBCL. CLINICAL TRIAL REGISTRATION: NCT04697160 (January 6, 2021).

The Randomised Controlled Trial at the Intersection of Research Ethics and Innovation

The randomised controlled trial (RCT) has been considered for a long time as the gold standard for evidence generation to support regulatory decision making for medicines. The randomisation procedure involves an ethical dilemma since it means leaving the treatment choice to chance. Although currently contested, the ethical justification for the RCT that has gained widespread acceptance is the notion of 'clinical equipoise'. This state exists when "there is no consensus within the expert clinical community about the comparative merits of the alternatives to be tested"; it is argued that this confers the ethical grounds for the conduct of an RCT. The prominent position of the RCT is being challenged by new therapeutic modalities for which this study design may be unsuitable. Moreover, alternative approaches to evidence generation represent another area where innovation may have implications for the relevance of the RCT. Against the backdrop of the debate around the equipoise principle and some recent therapeutic and data analytical innovations, the aim of this article is to explore the current standing of the RCT from a regulatory perspective.

Current landscape of clinical development and approval of advanced therapies

Advanced therapy medicinal products (ATMPs) are innovative therapies that mainly target orphan diseases and high unmet medical needs. The uncertainty about the product's benefit-risk balance at the time of approval, the limitations of nonclinical development, and the complex quality aspects of those highly individualized advanced therapies are playing a key role in the clinical development, approval, and post-marketing setting for these therapies. This article reviews the current landscape of clinical development of advanced therapies, its challenges, and some of the efforts several stakeholders are conducting to move forward within this field. Progressive iteration of the science, methodologically sound clinical developments, establishing new standards for ATMPs development with the aim to ensure consistency in clinical development, and the reproducibility of knowledge is required, not only to increase the evidence generation for approval but to set principles to achieve translational success in this field.

Reinforcing Collaboration and Harmonization to Unlock the Potentials of Advanced Therapy Medical Products: Future Efforts Are Awaited From Manufacturers and Decision-Makers

Some advanced therapy medicinal products (ATMPs) hold great promises for life-threatening diseases with high unmet needs. However, ATMPs are also associated with significant challenges in market access, which necessitates the joint efforts between all relevant stakeholders to navigate. In this review, we will elaborate on the importance of collaborations and harmonization across different stakeholders, to expedite the market access of promising ATMPs. Manufacturers of ATMPs should proactively establish collaborations with other stakeholders throughout the whole lifecycle of ATMPs, from early research to post-market activities. This covered engagements with (1) external developers (i.e., not-for-profit organizations and commercial players) to obtain complementary knowledge, technology, or infrastructures, (2) patient groups and healthcare providers to highlight their roles as active contributors, and (3) decision-makers, such as regulators, health technology assessment (HTA) agencies, and payers, to communicate the uncertainties in evidence package, where parallel consultation will be a powerful strategy. Harmonization between decision-makers is desired at (1) regulatory level, in terms of strengthening the international standardization of regulatory framework to minimize discrepancies in evidence requirements for market authorization, and (2) HTA level, in terms of enhancing alignments between regional and national HTA agencies to narrow inequity in patient access, and cross-border HTA cooperation to improve the quality and efficiency of HTA process. In conclusion, manufacturers and decision-makers shared the common goals to safeguard timely patient access to ATMPs. Collaboration and harmonization will be increasingly leveraged to enable the value delivery of ATMPs to all stakeholders.

An overview of cell and gene therapy development in China

China, the first country worldwide to approve a gene therapy in 2003, almost lost the advantage for a head start in cell and gene therapy (CGT) development due to a lack of clear and strict regulatory frameworks. The rapid advancements of CGTs' development worldwide as well as their therapeutic potential have triggered the government to conduct a spate of regulatory reforms in order to promote normative development of CGTs in China. Encouraged by policy support, the remarkable progress for CGTs in China has been observed over the past few years, thereby catapulting China back into the forefront of CGTs worldwide. This manuscript aims to provide an overview of regulatory reforms, the current development landscape of CGTs, as well as key contributors and challenges for CGT development in China.

Regulating innovation in the early development of cell therapies

Clinical need for paradigm shifts in efficacy and safety is driving the rapid and wide-ranging innovation in cell therapies for cancer beyond existing regulatory frameworks. Critical issues emerging during clinical trials frequently reflect unresolved elements of the regulation of innovation conundrum from earlier stages of development. We address this challenge using a global regulators’ perspective on the preclinical development of cell therapies, as a navigational aid to intended commercial use which maximises the clinical relevance of developmental data. We examine the implications of tumour targeting based on B cell, natural killer cell, conventional and unconventional T cell receptor domains; multiplex approaches; genetic manipulation strategies; and autologous versus allogeneic cell sources. We propose that detailed characterisation of both the cell source and final product is critical to optimising manufacture of individualised autologous or off the shelf allogeneic cell therapies, enabling product consistency to underpin extrapolation of clinical trial data to the expected commercial use. We highlight preclinical approaches to characterising target antigens including the Human Cell Atlas initiative, multi-dimensional cell culture, and safety testing against activated, proliferating or stressed control cells. Practical solutions are provided for preclinical toxicity studies when cell therapies target uniquely human tumour antigens, including illustrative mitigation measures for potential toxicity likely to support timely approval of first-in-human clinical trials. We recommend addressing the regulation of innovation conundrum through serial engagement between innovators and regulators early in the development of cell therapies for cancer, accelerating patient access while safeguarding against unacceptable toxicities.