Preclinical evaluation of ADVM-062, a novel intravitreal gene therapy vector for the treatment of blue cone monochromacy.

Blue cone monochromacy (BCM) is a rare X-linked retinal disease characterized by the absence of L- and M-opsin in cone photoreceptors, considered a potential gene therapy candidate. However, most experimental ocular gene therapies utilize subretinal vector injection which would pose a risk to the fragile central retinal structure of BCM patients. Here we describe the use of ADVM-062, a vector optimized for cone-specific expression of human L-opsin and administered using a single intravitreal (IVT) injection. Pharmacological activity of ADVM-062 was established in gerbils, whose cone-rich retina naturally lacks L-opsin. A single IVT administration dose of ADVM-062 effectively transduced gerbil cone photoreceptors and produced a de novo response to long-wavelength stimuli. To identify potential first-in-human doses we evaluated ADVM-062 in non-human primates. Cone-specific expression of ADVM-062 in primates was confirmed using ADVM-062.myc, a vector engineered with the same regulatory elements as ADVM-062. Enumeration of human OPN1LW.myc-positive cones demonstrated that doses ≥3 × 1010 vg/eye resulted in transduction of 18%-85% of foveal cones. A Good Laboratory Practice (GLP) toxicology study established that IVT administration of ADVM-062 was well tolerated at doses that could potentially achieve clinically meaningful effect, thus supporting the potential of ADVM-062 as a one-time IVT gene therapy for BCM.

Non-progressing cancer patients have persistent B cell responses expressing shared antibody paratopes that target public tumor antigens.

There is significant debate regarding whether B cells and their antibodies contribute to effective anti-cancer immune responses. Here we show that patients with metastatic but non-progressing melanoma, lung adenocarcinoma, or renal cell carcinoma exhibited increased levels of blood plasmablasts. We used a cell-barcoding technology to sequence their plasmablast antibody repertoires, revealing clonal families of affinity matured B cells that exhibit progressive class switching and persistence over time. Anti-CTLA4 and other treatments were associated with further increases in somatic hypermutation and clonal family size. Recombinant antibodies from clonal families bound non-autologous tumor tissue and cell lines, and families possessing immunoglobulin paratope sequence motifs shared across patients exhibited increased rates of binding. We identified antibodies that caused regression of, and durable immunity toward, heterologous syngeneic tumors in mice. Our findings demonstrate convergent functional anti-tumor antibody responses targeting public tumor antigens, and provide an approach to identify antibodies with diagnostic or therapeutic utility.

An Evaluation of the Pharmacodynamics, Safety, and Tolerability of the Potassium Binder RDX7675.

Hyperkalemia is common in patients with heart failure or chronic kidney disease, particularly those taking renin-angiotensin-aldosterone system inhibitors, and can cause arrhythmias and sudden cardiac death. The most widely used treatment, sodium polystyrene sulfonate (SPS), limits gastrointestinal potassium absorption, but has poor palatability. RDX7675 (RDX227675) is the calcium salt of a reengineered polystyrene sulfonate-based resin with improved palatability over SPS. The pharmacodynamic effects and safety of RDX7675 were assessed in a phase 1, single-center, randomized, active-controlled study. Healthy volunteers received nominal active doses of RDX7675 4.6 g twice a day (BID), 4.6 g 3 times a day (TID), 6.9 g BID, 13.7 g daily (QD), 9.2 g TID, or 13.7 g BID (n = 12 each), or equivalent doses of SPS (n = 3 each), for 4 days. RDX7675 dosing increased stool potassium excretion and decreased urinary potassium excretion from baseline. Stool potassium excretion increased by up to 1481 mg/day with RDX7675 (6.9 g BID), and urinary potassium excretion decreased by up to 939 mg/day (13.7 g BID). Similar levels of potassium excretion were observed using QD, BID, or TID dosing of a 13.7 g total daily RDX7675 dose. Few adverse events were reported. In conclusion, repeated oral dosing with RDX7675 over 4 days reduced potassium absorption in healthy volunteers; the results support QD dosing of RDX7675 in future clinical studies.