Investigation of Hydrophilic Auristatin Derivatives for Use in Antibody Drug Conjugates

Abstract

Antibody drug conjugates offer a targeted cancer treatment for the delivery of potent cytotoxic drugs. Derivatives of the natural product dolastatin 10 containing pyridines and other basic amines were examined with the objective of determining if a more hydrophilic auristatin derivative would be potent enough for use as part of an ADC. This may be advantageous if a less hydrophobic drug makes a better ADC. A pyridine derivative, monomethyl auristatin PYE, showed the greatest potency when tested in vivo. While only a modest tumor growth inhibition was observed when the HCC1954 human breast cancer xenografts were treated with"non-cleavable" linker ADCs, tumor regression was seen when treated with an enzymatically degradable "cleavable" linker ADC when conjugated to trastuzumab. Based on these studies, monomethyl auristatin PYE shows promise for use as an ADC payload.

Antibody–Drug Conjugate Payloads; Study of Auristatin Derivatives

“…Many research groups have studied auristatins with a focus mostly on the P1 and P5 subunits and these modifications have been extensively reviewed 16,50) (Fig. 3).…”

“…The MMAPYE (8) and aniline 17 were evaluated in vivo (data not shown in this paper). We identified that MMAPYE (8) was the payload with the best activity and the least toxicity in vivo 16) (17 showed signs of toxicity at the 4 mg/kg dose, pronounced body weight loss). It was successfully attached to a variety of linkers then conjugated to trastuzumab for evaluation as an ADC (Fig.…”

“…10). The SAR described in the chemical literature is significantly more limited 16,50,[53][54][55][56] for the P2-P4 modifications compared with the terminal amino acid variants. For the P2 subunit, limited substitution of the natural valine residue with leucine or isoleucine was previously reported without a significant impact in compound potency.…”

“…11,14) Over the last few decades, many research groups have studied auristatin analogues and its ADCs and this research area has been extensively reviewed both on academic and industrial sides. 11,16) Thus auristatins are attractive toxic compounds on ADCs and we also have investigated the structure-activity relationship (SAR) and auristatins ADCs to create the next generation ADCs. [17][18][19][20] In this review, our recent research regarding auristatin analogues is described.…”

Systematic identification of engineered methionines and oxaziridines for efficient, stable, and site-specific antibody bioconjugation

“…We chose to use the cathepsin B cleavable linker valine-citrulline for its improved effect over a non-cleavable linker (data not shown). We picked the microtubule inhibitor MMAF as the toxic payload due to its previously characterized strong potency in ADC formats and improved solubility compared to MMAE 25 . Both ADCs showed high potency in a HER2-positive breast cancer cell line, BT474-M1, compared to either trastuzumab alone or an aGFP Fab control (Fig.…”