Development of Novel CD47-Specific ADCs Possessing High Potency Against Non-Small Cell Lung Cancer in vitro and in vivo

Targeted therapies hold promise for efficiently and accurately delivering cytotoxic drugs directly to tumor tissue to exert anticancer effects. CD47 is a membrane protein expressed in a variety of malignant tumors and hematopoietic cells, which plays a key role in immune escape and tumor progression. Although CD47 immunocheckpoint therapy has been developed in recent years, many patients cannot benefit from it because of its low efficiency. To strengthen and extend the therapeutic efficacy of anti-CD47 monoclonal antibody (mAb), we used the newly developed 7DC2 and 7DC4 mAbs as the targeting payload adaptor and VCMMAE as the toxin payload to construct novel CD47-specific immunotoxin (7DC-VCMMAE) by engineering cysteine residues. These CD47-specific ADCs have the better cell penetration, excellent DAR, similar payload distribution and good antigen-binding affinity. In vitro, 7DC-VCMMAE treatment induced death of non-small cell lung cancer (NSCLC) cell lines 95D and SPC-A1, but not A549 that express low levels of CD47 on the cell membrane. This finding suggests that 7DC-VCMMAE may possess greater therapeutic effect on NSCLC tumors expressing a high level of CD47 antigen; however, 7DC-VCMMAE treatment also promoted phagocytosis of A549 cells by macrophages. In vivo, 7DC-VCMMAE treatment had remarkable antitumor effects in a NSCLC cell line-derived xenograft (CDX) mouse model based on nonobese diabetic/severe combined immunodeficient (NOD/SCID). In summary, this study combined VCMMAE with anti-CD47 mAbs, emphasizing a novel and promising immunotherapy method for direct killing of NSCLC, which provides a valuable new way to meet the needs of the cancer therapy field.

Five-year maintenance of clinical response and health-related quality of life improvements in patients with moderate-to-severe psoriasis treated with guselkumab: results from VOYAGE 1 and VOYAGE 2

BACKGROUND

Psoriasis is a chronic disease requiring long-term therapy.

OBJECTIVES

Physician- and patient-reported outcomes were evaluated through week 252 in VOYAGE 1 and VOYAGE 2.

METHODS

In total, 1829 patients were randomized at baseline to receive guselkumab 100 mg every 8 weeks, placebo or adalimumab. Patients receiving placebo crossed over to guselkumab at week 16. Patients receiving adalimumab crossed over to guselkumab at week 52 in VOYAGE 1, and randomized withdrawal and retreatment occurred at weeks 28-76 in VOYAGE 2; all patients then received open-label guselkumab through week 252. Efficacy and health-related quality of life (HRQoL) endpoints were analysed through week 252. Safety was monitored through week 264.

RESULTS

The proportions of patients in the guselkumab group who achieved clinical responses at week 252 in VOYAGE 1 and VOYAGE 2, respectively, were 84·1% and 82·0% [≥ 90% improvement in Psoriasis Area and Severity Index (PASI)]; 82·4% and 85·0% [Investigator's Global Assessment (IGA) 0 or 1]; 52·7% and 53·0% (100% improvement in PASI) and 54·7% and 55·5% (IGA 0). HRQoL endpoints were achieved as follows: 72·7% and 71·1% of patients (Dermatology Life Quality Index 0 or 1: no effect on patient's life); 42·4% and 42·0% [Psoriasis Symptoms and Signs Diary (PSSD) symptom score = 0] and 33·0% and 31·0% (PSSD sign score = 0). As measured in VOYAGE 2 only, approximately 45% of patients achieved ≥ 5-point reduction in Short Form-36 physical and mental component scores, and 80% reported no anxiety or depression (Hospital Anxiety and Depression Scale scores < 8). Similar findings were reported for adalimumab crossovers. These effects were maintained from week 52 in VOYAGE 1 and week 100 in VOYAGE 2. No new safety signals were identified.

CONCLUSIONS

Guselkumab maintains high levels of clinical response and improvement in patient-reported outcomes through 5 years in patients with moderate-to-severe psoriasis.

Safety of guselkumab in patients with moderate-to-severe psoriasis treated through 100 weeks: a pooled analysis from the randomized VOYAGE 1 and VOYAGE 2 studies

BACKGROUND

Long-term evaluation is required to confirm the safety profile of newer biologic agents.

OBJECTIVES

To report on pooled safety data from the ongoing VOYAGE 1 (NCT02207231) and VOYAGE 2 (NCT02207244) trials through 100 weeks of follow-up.

METHODS

Patients were randomized to either guselkumab 100 mg at weeks 0 and 4 and every 8 weeks thereafter; placebo at weeks 0, 4, 12 followed by guselkumab 100 mg at weeks 16 and 20 and every 8 weeks thereafter; or adalimumab 80 mg at week 0, 40 mg at week 1, and 40 mg every 2 weeks thereafter. Patients who received adalimumab crossed over to guselkumab at week 52 (VOYAGE 1) and at/after week 28 based on clinical response (VOYAGE 2). Open-label extensions, in which all patients received guselkumab, started at week 52 (VOYAGE 1) and week 76 (VOYAGE 2). Rates of adverse events (AEs) per 100 patient-years (PYs) are presented through 100 weeks of follow-up.

RESULTS

Through week 52, observed rates for guselkumab- and adalimumab-treated patients, respectively, were 262·45 per 100 PYs and 328·28 per 100 PYs for AEs, 6·20 per 100 PYs and 7·77 per 100 PYs for serious AEs (SAEs), 1·22 per 100 PYs and 1·79 per 100 PYs for serious infections (SIs), 0·28 per 100 PYs and 0·40 per 100 PYs for malignancies other than nonmelanoma skin cancers (NMSCs), 0·56 per 100 PYs and 0·40 per 100 PYs for NMSCs, and 0·47 per 100 PYs and 0·40 per 100 PYs for major adverse cardiovascular events (MACEs). Rates among patients treated with guselkumab through week 52 and week 100, respectively, were 262·45 per 100 PYs and 210·41 per 100 PYs for AEs, 6·20 and 6·29 per 100 PYs, for SAEs, 1·22 per 100 PYs and 1·06 per 100 PYs for SIs, 0·28 per 100 PYs and 0·38 per 100 PYs for malignancies, 0·56 per 100 PYs and 0·39 per 100 PYs for NMSCs, and 0·47 per 100 PYs and 0·38 per 100 PYs for MACEs. Among patients treated with adalimumab, rates of AEs, SAEs, SIs, malignancies, NMSCs, and MACEs showed some variability before and after crossover to guselkumab, although no new safety signals were noted after crossover.

CONCLUSIONS

The safety profile for guselkumab remains favourable through 100 weeks of treatment in patients with moderate-to-severe psoriasis.

Use of dose-exposure-response relationships in Phase 2 and Phase 3 guselkumab studies to optimize dose selection in psoriasis

BACKGROUND

Guselkumab is an anti-interleukin-23 monoclonal antibody for the treatment of moderate-to-severe psoriasis.

OBJECTIVE

To evaluate the association between dose-response and exposure-response of guselkumab in Phase 2 and Phase 3 studies to optimize dose selection.

METHODS

Serum guselkumab concentrations in Phase 2 and Phase 3 studies (VOYAGE 1 and VOYAGE 2) were measured using a validated immunoassay. Efficacy assessments included Physician's Global Assessment (PGA), Investigator's Global Assessment (IGA) and Psoriasis Area and Severity Index (PASI).

RESULTS

In Phase 2, a positive dose-response relationship was observed for PASI and PGA (5-mg through 100-mg dose regimens). Exposure-response analysis showed that patients with steady-state trough serum guselkumab concentrations ≥0.67 μg/mL achieved the highest levels of efficacy (PGA 0/1: 90.0%; PGA 0: 70.0%). The guselkumab 100-mg every 8-week (q8w) dose regimen, safe and well-tolerated in Phase 2, provided the highest serum guselkumab concentrations among all regimens studied and was selected for Phase 3. In Phase 3, 72.5% of patients achieved guselkumab concentrations ≥0.67 μg/mL at week 28, the level associated with the highest clinical responses in Phase 2, with patients achieving response rates of IGA 0/1: 91.2%, IGA 0: 55.3%, PASI 90: 83.8% and PASI 100: 49.1% at week 28.

CONCLUSION

The 100-mg guselkumab q8w dose regimen, based on the dose-exposure-response relationship from the Phase 2 study, produced the target serum concentration associated with high-level efficacy in the majority of patients in Phase 3. Phase 3 data further confirmed that guselkumab 100mg q8w is the optimum dosing regimen for treating patients with moderate-to-severe psoriasis.

Effects of sequential deletions of residues from the N- or C-terminus on the functions of epsilon subunit of the chloroplast ATP synthase

Ten truncated mutants of chloroplast ATP synthase epsilon subunit from spinach (Spinacia oleracea), which had sequentially lost 1-5 amino acid residues from the N-terminus and 6-10 residues from the C-terminus, were generated by PCR. These mutants were overexpressed in Escherichia coli, reconstituted with soluble and membrane-bound CF(1), and the ATPase activity and proton conductance of thylakoid membrane were examined. Deletions of as few as 3 amino acid residues from the N-terminus or 6 residues from the C-terminus of epsilon subunit significantly affected their ATPase-inhibitory activity in solution. Deletion of 5 residues from the N-terminus abolished its abilities to inhibit ATPase activity and to restore proton impermeability. Considering the consequence of interaction of epsilon and gamma subunit in the enzyme functions, the special interactions between the epsilon variants and the gamma subunit were detected in the yeast two-hybrid system and in vitro binding assay. In addition, the structures of these mutants were modeled through the SWISS-MODEL Protein Modeling Server. These results suggested that in chloroplast ATP synthase, both the N-terminus and C-terminus of the epsilon subunit show importance in regulation of the ATPase activity. Furthermore, the N-terminus of the epsilon subunit is more important for its interaction with gamma and some CF(o) subunits, and crucial for the blocking of proton leakage. Compared with the epsilon subunit from E. coli [Jounouchi, M., Takeyama, M., Noumi, T., Moriyama, Y., Maeda, M., and Futai, M. (1992) Arch. Biochem. Biophys. 292, 87-94; Kuki, M., Noumi, T., Maeda, M., Amemura, A., and Futai, M. (1988) J. Biol. Chem. 263, 4335-4340], the chloroplast epsilon subunit is more sensitive to N-terminal or C-terminal truncations.

Photoinactivation of photosystem II by cumulative exposure to short light pulses during the induction period of photosynthesis

Photoinactivation of Photosystem (PS) II in vivo was investigated by cumulative exposure of pea, rice and spinach leaves to light pulses of variable duration from 2 to 100 s, separated by dark intervals of 30 min. During each light pulse, photosynthetic induction occurred to an extent depending on the time of illumination, but steady-state photosynthesis had not been achieved. During photosynthetic induction, it is clearly demonstrated that reciprocity of irradiance and duration of illumination did not hold: hence the same cumulative photon exposure (mol m(-2)) does not necessarily give the same extent of photoinactivation of PS II. This contrasts with the situation of steady-state photosynthesis where the photoinactivation of PS II exhibited reciprocity of irradiance and duration of illumination (Park et al. (1995) Planta 196: 401-411). We suggest that, for reciprocity to hold between irradiance and duration of illumination, there must be a balance between photochemical (qP) and non-photochemical (NPQ) quenching at all irradiances. The index of susceptibility to light stress, which represents an intrinsic ability of PS II to balance photochemical and non-photochemical quenching, is defined by the quotient (1-qP)/NPQ. Although constant in steady-state photosynthesis under a wide range of irradiance (Park et al. (1995). Plant Cell Physiol 36: 1163-1169), this index of susceptibility for spinach leaves declined extremely rapidly during photosynthetic induction at a given irradiance, and, at a given cumulative photon exposure, was dependent on irradiance. During photosynthetic induction, only limited photoprotective strategies are developed: while the transthylakoid pH gradient conferred some degree of photoprotection, neither D1 protein turnover nor the xanthophyll cycle was operative. Thus, PS II is more easily photoinactivated during photosynthetic induction, a phenomenon that may have relevance for understorey leaves experiencing infrequent, short sunflecks.

Malate regulation of Mg(2+)-ATPase of chloroplast coupling factor 1

The regulatory effects of malate on chloroplast Mg(2+)-ATPase were investigated and the mechanism was discussed. Malate stimulated methanol-activated membrane-bound and isolated CF1 Mg(2+)-ATPase activity. The γ subunit of CF1 may be involved in malate regulation of the enzyme function. Modification of γ subunit at one site of the peptide by NEM may affect malate stimulation of ATPase while at another site may have no effect. The effect of malate on the Mg(2+)-ATPase was also controlled by the Mg(2+)/ATP ratio in the reaction medium. The enhancing effect of malate on Mg(2+)-ATPase activity depended on the presence of high concentrations of Mg(2+) in the reaction mixture. Kinetic study showed that malate raised the Vmax of catalysis without affecting the Km for Mg(2+) ATP. The experiments imply that the stimulation of Mg(2+)-ATPase by malate is probably correlated with the Pi binding site on the enzyme. The regulation of ATPase activity by malate in chloroplasts may be relevant to its function in vivo.