A Novel Anti-CD22 Anthracycline-Based Antibody–Drug Conjugate (ADC) That Overcomes Resistance to Auristatin-Based ADCs

Abstract

Purpose: We are interested in identifying mechanisms of resistance to the current generation of antibody-drug conjugates (ADC) and developing ADCs that can overcome this resistance.Experimental Design: Pinatuzumab vedotin (anti-CD22-vc-MMAE) and polatuzumab vedotin are ADCs that contain the microtubule inhibitor monomethyl auristatin E (MMAE) attached to the antibody by the proteasecleavable linker maleimidocaproyl-valine-citrulline-p-aminobenzoyloxycarbonyl (MC-vc-PAB). Early clinical trial data suggest that these ADCs have promising efficacy for the treatment of nonHodgkin lymphoma (NHL); however, some patients do not respond or become resistant to the ADCs. Anthracyclines are very effective in NHL, but ADCs containing the anthracycline doxorubicin were not clinically efficacious probably due to the low drug potency and inadequate linker technology. The anthracycline analogue PNU-159682 is thousands of times more cytotoxic than doxorubicin, so we used it to develop a new class of ADCs. We used the same MC-vc-PAB linker and antibody in pinatuzumab vedotin but replaced the MMAE with a derivative of PNU-159682 to make anti-CD22-NMS249 and tested it for in vivo efficacy in xenograft tumors resistant to MMAE-based ADCs.Results: We derived cell lines from in vivo xenograft tumors that were made resistant to anti-CD22-vc-MMAE and anti-CD79b-vc-MMAE. We identified P-gp (ABCB1/MDR1) as the major driver of resistance to the vc-MMAE-based conjugates. Anti-CD22-NMS249 was at least as effective as anti-CD22-vc-MMAE in xenograft models of the parental cell lines and maintained its efficacy in the resistant cell lines.Conclusions: These studies provide proof of concept for an anthracycline-based ADC that could be used to treat B-cell malignancies that are resistant to vc-MMAE conjugates.

Caveolae-Mediated Endocytosis as a Novel Mechanism of Resistance to Trastuzumab Emtansine (T-DM1)

“…In a similar fashion, cell line models made resistant to CD22-or CD79b-targeting ADCs employing the vcMMAE linker-payload remained sensitive to the respective ADCs delivering a different payload (e.g., PNU-159682; ref. 29). Thus, by swapping each module of an ADC with a different functional group, ADC activity can be modulated.…”

Highly Potent, Anthracycline-based Antibody–Drug Conjugates Generated by Enzymatic, Site-specific Conjugation

“…1D). A similar linkerpayload for maleimide-based conjugation to thiols, referred to as NMS249, has recently been described and was evaluated in the context of a CD22-specific ADC (33).…”

“…PNU-159682 was described to be several orders of magnitude more potent than doxorubicin (34) and has recently shown promise as a payload for ADCs in the context of conventional chemical conjugation (32,33). Indeed, when conjugated to trastuzumab, a significantly increased cytotoxic activity was achieved in comparison with maytansine conjugates and even cells with moderate HER2 expression levels, that were not sensitive to Kadcyla, could efficiently be killed (Figs.…”

“…Finally, alternative payloads with substantially higher potency than microtubuledisrupting agents are being investigated, including pyrrolobenzodiazepine (PBD) dimers (29), enedyenes such as calicheamicin (30), indilino-benzodiazepine (IBD) pseudodimers (termed IGNs; ref. 31), as well as novel anthracylines (32,33).…”

Differential killing of CD56-expressing cells by drug-conjugated human antibodies targeting membrane-distal and membrane-proximal non-overlapping epitopes

“…31,32 It has been reported that in some tumors with high multi-drug resistance (MDR) activity, PBD-conjugated ADCs can overcome the resistance mechanism and remain active in acute myeloid leukemia model. 33 We tested m906MMAF initially and compared it with m906PBD (data not shown), and found that the latter was more potent in killing IMR-05 cells.…”