Baricitinib in patients with moderate-to-severe atopic dermatitis and inadequate response to topical corticosteroids: results from two randomized monotherapy phase III trials

BACKGROUND

Baricitinib, an oral selective Janus kinase 1 and 2 inhibitor, effectively reduced atopic dermatitis (AD) severity in a phase II study with concomitant topical corticosteroids.

OBJECTIVES

To evaluate the efficacy and safety of baricitinib in patients with moderate-to-severe AD who had an inadequate response to topical therapies.

METHODS

In two independent, multicentre, double-blind, phase III monotherapy trials, BREEZE-AD1 and BREEZE-AD2, adults with moderate-to-severe AD were randomized 2 : 1 : 1 : 1 to once-daily placebo, baricitinib 1 mg, 2 mg, or 4 mg for 16 weeks.

RESULTS

At week 16, more patients achieved the primary end point of Validated Investigator's Global Assessment of AD (0, 1) on baricitinib 4 mg and 2 mg compared with placebo in BREEZE-AD1 [N = 624; baricitinib 4 mg 16·8% (P < 0·001), 2 mg 11·4% (P < 0·05), 1 mg 11·8% (P < 0·05), placebo 4·8%], and BREEZE-AD2 [N = 615; baricitinib 4 mg 13·8% (P = 0·001), 2 mg 10·6% (P < 0·05), 1 mg 8·8% (P = 0·085), placebo 4·5%]. Improvement in itch was achieved as early as week 1 for 4 mg and week 2 for 2 mg. Improvements in night-time awakenings, skin pain and quality-of-life measures were observed by week 1 for both 4 mg and 2 mg (P ≤ 0·05, all comparisons). The most common adverse events in patients treated with baricitinib were nasopharyngitis and headache. No cardiovascular events, venous thromboembolism, gastrointestinal perforation, significant haematological changes, or death were observed with any baricitinib dosage.

CONCLUSIONS

Baricitinib improved clinical signs and symptoms in patients with moderate-to-severe AD within 16 weeks of treatment and induced rapid reduction of itch. The safety profile remained consistent with prior findings from baricitinib clinical development in AD, with no new safety concerns.

Localization of pancreatic cancer with radiolabeled monoclonal antibody PAM4

Experimental animal studies were performed with (111)In-labeled PAM4 anti-MUC1 antibody along with (111)In-labeled control antibody. Tumor uptake of radiolabeled PAM4 was significantly higher than for the control antibody at all time points. When normalized to a blood dose of 1500 cGy as an estimate of myelotoxicity, (90)Y-labeled PAM4 would provide 5344 cGy to the tumor, whereas an equitoxic dose of (90)Y-labeled control antibody would provide only 862 cGy to the tumor. In addition to the animal studies, five patients with proven pancreatic cancer were administered either (131)I-PAM4 IgG (n=2) or 99mTc-PAM4 Fab' (n=3). Tumor targeting was observed in four out of five patients. By immunohistochemistry, PAM4 was non-reactive with tumor from the one patient not targeted. Dosimetry from the patients given (131)I-PAM4 predicted that tumors would receive 10-20 cGy/mCi with tumor/red marrow dose ratios ranging from 3 to 10. Based upon these results, we have established a phase-I (111)In-labeled PAM4 imaging and (90)Y-labeled PAM4 therapy trial.

Epithelial mucin-1 (MUC1) expression and MA5 anti-MUC1 monoclonal antibody targeting in multiple myeloma

Multiple myeloma (MM) is the second most common hematological cancer in the United States. It is typically incurable, even with myeloablative chemotherapy and stem-cell transplantation. The epithelial mucin-1 (MUC1) glycoprotein is expressed by normal and malignant epithelial cells but has also been shown to be expressed by MM cells. MUC1 is a useful antigenic target in solid tumors for clinical diagnostic and therapeutic monoclonal antibody (mAb)-based approaches. The MA5 mAb, as well as other anti-MUC1 mAbs reactive with the MUC1 variable number tandem repeat domain, exhibited moderate to strong reactivity with both MM cell lines and clinical samples. To explore the biochemical nature and potential of MUC1 as an antigenic target in MM, studies were performed to: (a) compare the mRNA and the MUC1 glycoprotein species between epithelial cancer and MM cell lines; and (b) develop and use a human MM tumor xenograft model system to study the biodistribution of the MA5 mAb. MA5 mAb was strongly reactive with six of eight human MM cell lines by flow cytometry. In seven of eight MM patient samples (bone marrow and/or peripheral blood) reactivity was found in 10-90% of the cells, whereas normal control (n = 5) and leukemia and lymphoma (n = 5) cells showed only 0-6% reactivity. 125I-labeled MA5 whole-cell binding studies showed quantitatively similar amounts of binding between strongly positive MM lines and high-MUC1-expressing breast carcinoma lines. mRNA expression was assessed by Northern blotting and reverse transcription-PCR. MM cell lines were positive by both methods, with strong similarity in the sizes of the mRNAs and cDNAs that were obtained. Finally, biodistribution experiments were carried out with 131I-labeled MA5 versus a nonbinding control 125I-labeled mAb in a s.c. MM xenograft model. Selective MM tumor uptake of the MA5 mAb was demonstrated, with a potential for delivering a tumor radiation absorbed dose of 8540 cGy/mCi of injected dose compared with 3099 cGy/mCi of tumor-absorbed dose delivered by nonspecific antibody.

Radioimmunotherapy of experimental pancreatic cancer with 131I-labeled monoclonal antibody PAM4

We examined the therapeutic efficacy of 131I-labeled murine monoclonal antibody (MAb) PAM4 against human pancreatic cancers carried as xenografts in athymic nude mice. Animals bearing the CaPan1 tumor (0.2 cm3) were either untreated or were given, 131I-labeled nonspecific Ag8 antibody. By week 7 mean tumor size had grown 16.5 +/- 8.4-fold and 4.2 +/- 2.5-fold for the untreated and 131I-Ag8-treated animals, respectively. In contrast, animals administered 131I-PAM4 exhibited marked regression of tumors to an average of 15% of initial tumor volume. Since most pancreatic cancer patients present with large tumor burdens, the limitation of 131I-PAM4 treatment with respect to initial tumor size was investigated in animals bearing tumors of approximately 0.5 cm3, 1.0 cm3 and 2.0 cm3. Significant extension of survival time (>3-fold increase) was noted for both the 0.5 cm3 and 1.0 cm3 131I-PAM4-treated groups, compared to their respective untreated controls. Even in the group bearing large 2.0-cm3 tumors, survival was increased 2-fold over the control group. To further improve anti-tumor effects in large tumors, 2 injections of 131I-PAM4 were administered at a 4-week interval to animals bearing tumors of approximately 1.0 cm3. Significant extended survival was noted for the group receiving 2 doses when compared to the group receiving only 1 dose.

A phase II trial of deferoxamine in patients with hormone-refractory metastatic prostate cancer

The management of hormone-refractory metastatic prostate cancer remains a therapeutic dilemma. We report the results of a phase II trial with deferoxamine administrated at a dose of 50 mg/kg (maximum dose 5 g) administered intravenously over 8 hr daily, repeated for 5 days at 4-week intervals for 2 courses. Fourteen patients with advanced hormone-refractory prostate cancer were treated and 28 courses were delivered. Essentially no toxicity was observed. Using combined clinical and prostate-specific antigen (PSA) criteria. 13 of 14 patients had disease progression. However, 9 of 14 patients had stable measurable or evaluable disease and progressed solely based on PSA criteria. Deferoxamine in this dose and schedule has no activity in hormone-refractory prostate cancer. Further investigation of the effect of deferoxamine on PSA production/expression is warranted.

Inhibition of lymphoma growth in vivo by combined treatment with hydroxyethyl starch deferoxamine conjugate and IgG monoclonal antibodies against the transferrin receptor

Synergistic inhibition of hematopoietic tumor growth can be observed in vitro when the iron chelator deferoxamine (DFO) is used in combination with an IgG mAb against the anti-transferrin receptor antibody (ATRA). Our goal was to ascertain whether similar findings could be seen in vivo. A high molecular weight conjugate of deferoxamine, known as hydroxyethyl starch (HES) DFO or HES-DFO, was tested in conjunction with C2, a well-defined rat antimouse transferrin receptor mAb, against the 38C13 tumor in C3H/HeN mice. It was shown that while neither HES-DFO alone nor C2 alone produced consistent, significant inhibition of tumor growth, the combination of HES-DFO and C2 produced virtually complete inhibition of initial tumor outgrowth. The latter combination failed, however, to inhibit the growth of established tumors. It was then found that when C2 was used in conjunction with RL34, another IgG ATRA, the two ATRAS were themselves capable of causing synergistic inhibition of the growth of 38C13 in vitro. When the two IgG ATRAS were used together in vivo, regressions of established tumors were observed. Moreover, the addition of HES-DFO to the IgG ATRA pair then caused more frequent regressions. Although there was never any obvious toxicity seen with a single IgG ATRA, the use of the IgG ATRA pair was associated with sporadic mortality. In addition, although HES-DFO by itself was also not associated with any obvious toxicity, combined treatment with HES-DFO and a single ATRA resulted in death due to bacterial infection in about half of the mice after 10-15 days. Combined treatment with HES-DFO and the ATRA pair resulted in death attributed to infection in nearly all of the mice after 6 days. Thus, an iron deprivation treatment protocol with HES-DFO and IgG ATRAS produced both a significant antitumor effect and an increased risk of infection in a murine model system.

Characterization of monoclonal antibody PAM4 reactive with a pancreatic cancer mucin

A monoclonal antibody (MAb), PAM4, having reactivity with pancreatic carcinoma has been developed. PAM4 is an IgG1 immunoglobulin produced by immunization of mice with mucin purified from the xenografted RIP1 human pancreatic carcinoma. An immunohistochemical study of normal adult tissues showed the PAM4 reactive epitope to be restricted to the gastrointestinal tract and absent from normal pancreas. In neoplastic tissue, PAM4 was reactive with 85% of the pancreatic carcinomas, approximately half of the colon cancers and none of the breast, ovarian, prostate, renal and liver cancers. PAM4 was, in general, non-reactive with pancreatitis specimens whereas CA19.9 and DUPAN2 were strongly reactive with each one. Treatment of the mucin antigen by heating, reduction of disulfide bonds, or protease digestion abolished immunoreactivity with PAM4. Treatment of the mucin by neuraminidase or periodate oxidation reduced immunoreactivity but did not completely abolish it. Our data are consistent with the proposal that the PAM4 epitope is a conformationally dependent peptide epitope and that certain carbohydrate structures are necessary in order to maintain the correct peptide conformation. The high specificity and intense reactivity of PAM4 with pancreatic carcinoma tissue suggests that the antibody may prove useful for in vitro diagnostic assays as well as in vivo targeting of diagnostic and therapeutic agents.