Accelerating development of engineered T cell therapies in the EU: current regulatory framework for studying multiple product versions and T2EVOLVE recommendations

To accelerate the development of Advanced Therapy Medicinal Products (ATMPs) for patients suffering from life-threatening cancer with limited therapeutic options, regulatory approaches need to be constantly reviewed, evaluated and adjusted, as necessary. This includes utilizing science and risk-based approaches to mitigate and balance potential risks associated with early clinical research and a more flexible manufacturing paradigm. In this paper, T2EVOLVE an Innovative Medicine Initiative (IMI) consortium explores opportunities to expedite the development of CAR and TCR engineered T cell therapies in the EU by leveraging tools within the existing EU regulatory framework to facilitate an iterative and adaptive learning approach across different product versions with similar design elements or based on the same platform technology. As understanding of the linkage between product quality attributes, manufacturing processes, clinical efficacy and safety evolves through development and post licensure, opportunities are emerging to streamline regulatory submissions, optimize clinical studies and extrapolate data across product versions reducing the need to perform duplicative studies. It is worth noting that this paper is focusing on CAR- and TCR-engineered T cell therapies but the concepts may be applied more broadly to engineered cell therapy products (e.g., CAR NK cell therapy products)

Accelerating development of engineered T cell therapies in the EU: current regulatory framework for studying multiple product versions and T2EVOLVE recommendations

To accelerate the development of Advanced Therapy Medicinal Products (ATMPs) for patients suffering from life-threatening cancer with limited therapeutic options, regulatory approaches need to be constantly reviewed, evaluated and adjusted, as necessary. This includes utilizing science and risk-based approaches to mitigate and balance potential risks associated with early clinical research and a more flexible manufacturing paradigm. In this paper, T2EVOLVE an Innovative Medicine Initiative (IMI) consortium explores opportunities to expedite the development of CAR and TCR engineered T cell therapies in the EU by leveraging tools within the existing EU regulatory framework to facilitate an iterative and adaptive learning approach across different product versions with similar design elements or based on the same platform technology. As understanding of the linkage between product quality attributes, manufacturing processes, clinical efficacy and safety evolves through development and post licensure, opportunities are emerging to streamline regulatory submissions, optimize clinical studies and extrapolate data across product versions reducing the need to perform duplicative studies. It is worth noting that this paper is focusing on CAR- and TCR-engineered T cell therapies but the concepts may be applied more broadly to engineered cell therapy products (e.g., CAR NK cell therapy products)

Structural Determinants for the Binding of Morphinan Agonists to the μ-Opioid Receptor

Atomistic descriptions of the μ-opioid receptor (μOR) noncovalently binding with two of its prototypical morphinan agonists, morphine (MOP) and hydromorphone (HMP), are investigated using molecular dynamics (MD) simulations. Subtle differences between the binding modes and hydration properties of MOP and HMP emerge from the calculations. Alchemical free energy perturbation calculations show qualitative agreement with in vitro experiments performed in this work: indeed, the binding free energy difference between MOP and HMP computed by forward and backward alchemical transformation is 1.2±1.1 and 0.8±0.8 kcal/mol, respectively, to be compared with 0.4±0.3 kcal/mol from experiment. Comparison with an MD simulation of μOR covalently bound with the antagonist β-funaltrexamine hints to agonist-induced conformational changes associated with an early event of the receptor’s activation: a shift of the transmembrane helix 6 relative to the transmembrane helix 3 and a consequent loss of the key R165-T279 interhelical hydrogen bond. This finding is consistent with a previous proposal suggesting that the R165-T279 hydrogen bond between these two helices indicates an inactive receptor conformation

Free energy differences (in kcal/mol) for the described transformations.

<p>Error estimates are included.</p><p>^a Calculated as </p><p></p><p></p><p><mi>Δ</mi><mi>Δ</mi></p><p><mi>G</mi></p><p>MOP<mo>→</mo>HMP</p><p>exp<mo>.</mo></p><p></p><mo>=</mo><mi>Δ</mi><p><mi>G</mi></p><p>bind</p><p>HMP<mo stretchy="false">(</mo>exp<mo>.</mo><mo stretchy="false">)</mo></p><p></p><mo>−</mo><mi>Δ</mi><p><mi>G</mi></p><p>bind</p><p>MOP<mo stretchy="false">(</mo>exp<mo>.</mo><mo stretchy="false">)</mo></p><p></p><mo>=</mo><mi>R</mi><mi>T</mi>ln<p><mo>[</mo></p><p></p><p></p><p></p><p><mi>K</mi><mi>i</mi></p><p>HMP<mo stretchy="false">(</mo>exp<mo>.</mo><mo stretchy="false">)</mo></p><p></p><p></p><mo>/</mo><p></p><p><mi>K</mi><mi>i</mi></p><p>MOP<mo stretchy="false">(</mo>exp<mo>.</mo><mo stretchy="false">)</mo></p><p></p><p></p><p></p><p></p><mo>]</mo><p></p><mo>.</mo><p></p><p></p><p></p><p></p><p>Free energy differences (in kcal/mol) for the described transformations.</p

Representative structure of the MD simulations for (A) the MOP-μOR and (B) the HMP-μOR complexes obtained from clustering analysis.

<p>The ligand carbon atoms are in orange. H-bonds and salt-bridges are shown in green and magenta dashed lines, respectively. For clarity hydrogen atoms of the ligands and the μOR residues are not shown. H297 is monoprotonated at the Nε atom.</p

Conformational change of μOR EL3 observed in the case of MOP binding.

<p>E310 in EL3 forms a salt-bridge with K233 (magenta dashed lines), which remains until the end of the simulation.</p

Molecular structures of morphine and hydromorphone.

<p>Molecular structures of morphine and hydromorphone.</p

Schematic model of the agonist-induced μOR conformational change into an active-like state.

<p>Schematic model of the agonist-induced μOR conformational change into an active-like state.</p

The thermodynamic cycle for computing the free energy difference between MOP and HMP upon binding to μOR: ΔΔGbind=ΔGbindMOP−ΔGbindHMP=ΔGMOP→HMPbound−ΔGMOP→HMPunbound.

<p>The unbound state requires transformation of the ligands alone in solution, since the receptor is the same in both cases.</p

Arrangements of aromatic residues at the μOR orthosteric binding site upon binding with (A) MOP and with (B) HMP.

<p>Arrangements of aromatic residues at the μOR orthosteric binding site upon binding with (A) MOP and with (B) HMP.</p