This year’s American Society of Clinical Oncology (ASCO) annual meeting, which is being held in Chicago, began on Friday and goes through Tuesday.

Sunday started with a poster session in which im­por­tant new re­search findings were summarized on posters dis­played throughout a large conference hall.

The stud­ies pre­sented during the session were on a wide variety of myeloma-related topics, in­clud­ing new treat­ments being devel­oped for myeloma, cur­rently used regi­mens, smol­der­ing mul­ti­ple myeloma, and findings on initial ther­apy.

Some of the posters in­cluded pre­lim­i­nary results from on­go­ing clin­i­cal trials.  Others described the design of on­go­ing clin­i­cal trials for which results are not yet avail­able.

This up­date covers many of the myeloma-related stud­ies pre­sented during Sunday’s poster session.

TH-302

The session in­cluded a poster summarizing initial results from a Phase 1 study of TH-302 plus dexa­metha­sone (Decadron) in heavily pre­treated myeloma patients (abstract; poster [pdf] courtesy of Dr. Irene Gho­bri­al).

TH-302 is being devel­oped by Threshold Pharma­ceu­ticals (NASDAQ: THLD) and the German pharma­ceut­i­cal com­pany Merck KGaA. TH-302 is a drug that is activated under low oxygen level con­di­tions, which are common in tumors and the bone mar­row of people with blood cancers. It is cur­rently also being in­ves­ti­gated in a range of solid tumors.

The study in­cluded 13 patients with a median age of 59 years who had re­ceived a median of six prior lines of ther­apy.

They were treated with one of three dif­fer­en­t doses of TH-302 plus dexa­meth­a­sone.

Of the 12 patients eval­u­ated for re­sponse, 17 per­cent achieved a partial re­sponse, 17 per­cent reached a minimal re­sponse, and 67 per­cent had stable dis­ease.

The lower doses tested appear safe, but the highest dose was asso­ci­ated with severe side effects.

The authors point out that Velcade will be added to the com­bi­na­tion for Phase 2 of the study.

Kyprolis

The session in­cluded two posters about Kyprolis (car­filz­o­mib), which was approved by the U.S. Food and Drug Admin­istra­tion (FDA) for the treat­ment of re­lapsed and re­frac­tory mul­ti­ple myeloma last year.

The first poster summarized the findings of a Phase 1/2 study that in­ves­ti­gated the safety and ef­fi­cacy of Kyprolis when substituted for Velcade (bor­tez­o­mib) in Velcade-based regi­mens on which patients had progressed (abstract; poster [pdf] courtesy of Dr. James Berenson).

The study in­cluded 37 patients who had re­ceived a median of five prior ther­a­pies, in­clud­ing two Velcade-based com­bi­na­tions.

The results show that 43 per­cent of patients responded when Velcade was replaced with Kyprolis, with 8 per­cent achieving a com­plete re­sponse, 16 per­cent a very good partial re­sponse, and 19 per­cent a partial re­sponse.

The median time to pro­gres­sion was 9.9 months, and the median over­all sur­vival was 15.8 months.

The most common severe side effects in­cluded low lym­pho­cyte levels (35 per­cent), low platelet counts (24 per­cent), low white blood cell counts (11 per­cent), and low red blood cell counts (3 per­cent).

The sec­ond Kyprolis-related poster described results of a retro­spec­tive analysis of heart-related compli­ca­tions in heavily pre­treated myeloma patients who re­ceived treat­ment with Kyprolis.  The patients were given Kyprolis on a compassionate use basis at the University of Arkansas for Medical Sciences start­ing in 2009 (abstract; poster [pdf] courtesy of Dr. Saad Usmani).

The analysis in­cluded data from 143 patients with a median age of 61 years.  They had re­ceived a median of seven prior ther­a­pies; 92 per­cent had re­ceived a stem cell trans­plant, and 74 per­cent had re­ceived two or more trans­plants.

During the first 28-day cycle of treat­ment, patients re­ceived Kyprolis with dexa­meth­a­sone, and the Kyprolis dosing was com­parable to the cur­rent FDA-approved dosing regi­men.

During the sec­ond and later cycles, Kyprolis's dose could be in­creased, and other anti-myeloma ther­a­pies could be added to the treat­ment regi­men.

The results show that 19 per­cent of patients ex­peri­enced a serious heart-related com­pli­ca­tion, 78 per­cent of whom had preexisting risk factors for heart-related com­pli­ca­tions. Nine per­cent of patients re­quired hospi­tal­iza­tion.

The re­searchers point out that the reasons for these heart-related com­pli­ca­tions could not be definitively de­ter­mined because of the retro­spec­tive nature of the analysis, but sug­gest using Kyprolis with caution in patients with a history of serious cardiac dis­ease.

Pomalyst

The session also in­cluded sev­er­al posters about Pomalyst (poma­lido­mide), which was approved earlier this year by the FDA for the treat­ment of re­lapsed and re­frac­tory myeloma.

One poster summarized the results of a Phase 1 study of Pomalyst in com­bi­na­tion with Velcade and low-dose dexa­meth­a­sone in re­lapsed and re­frac­tory mul­ti­ple myeloma patients (abstract; poster [PDF] courtesy of Dr. Paul Richardson).

The study in­cluded 22 patients with a median age of 57 years who had re­ceived a median of two prior lines of ther­a­pies.

Among the 20 patients eval­u­ated for re­sponse, the over­all re­sponse rate was 75 per­cent.  Specifically, 5 per­cent achieved a com­plete re­sponse, 25 per­cent a very good partial re­sponse, and 45 per­cent a partial re­sponse.

The most common severe side effects were low white blood cell counts (32 per­cent) and low platelet counts (21 per­cent).

The sec­ond Pomalyst poster showed the results of a Phase 1/2 study of Pomalyst in com­bi­na­tion with Doxil (doxorubicin lipo­somal) and dexa­meth­a­sone in re­lapsed and re­frac­tory mul­ti­ple myeloma patients (abstract; poster [pdf] courtesy of Dr. James Hilger).

The study in­cluded 27 patients with a median age of 69 years who had re­ceived a median of five prior ther­a­pies.

Overall, 33 per­cent achieved a partial re­sponse. In addi­tion, 4 per­cent achieved a minimal re­sponse and 26 per­cent reached stable dis­ease.

The most common severe side effects were low white blood cell counts, in­clud­ing low leukocyte counts (41 per­cent), low neu­tro­phil counts (37 per­cent), and low lym­pho­cyte counts (30 per­cent).

Since more than half of the patients initially en­rolled in the study ex­peri­enced low white blood cell counts, the Pomalyst dose will be lowered from 4 mg to 3 mg for any addi­tional patients en­rolled in the study.

Another poster in­cluded initial results of a Phase 1 study investigating the ef­fi­cacy and safety of Pomalyst plus low-dose dexa­meth­a­sone in re­lapsed and re­frac­tory mul­ti­ple myeloma patients with kidney im­pair­ment (abstract).

The study in­cluded 11 re­lapsed and re­frac­tory myeloma patients, eight with nor­mal kidney function and three with im­paired kidney function that did not re­quire dialysis.  Addi­tional patients, in­clud­ing those re­quir­ing dialysis, are being recruited.

The median age of the par­tic­i­pants so far is 66 years, and they had re­ceived a median of four prior lines of ther­apy.

Patients re­ceived 2 mg or 4 mg of Pomalyst, de­pending on their kidney function.

Among the 11 patients eval­u­ated for re­sponse, the over­all re­sponse rate was 27 per­cent, which is con­sis­tent with results from other stud­ies of this com­bi­na­tion.

The most common severe side effects were low white blood cell counts (50 per­cent for those with nor­mal kidney function versus 33 per­cent for those with im­paired kidney function), in­fec­tions (25 per­cent versus 66 per­cent), and anemia (25 per­cent versus 33 per­cent).

No patients with kidney im­pair­ment re­quired dose re­duc­tions or dis­con­tinued treat­ment due to side effects.  Additionally, the length of time on treat­ment was similar for both groups of patients (4.1 months for patients with nor­mal kidney function and 3.9 months for those with im­paired kidney function).

Rapidity Of Re­sponse To Initial Therapy

Another poster summarized the results of a retro­spec­tive analysis that in­ves­ti­gated the implications of rapidity of re­sponse to initial ther­apy (abstract; poster [pdf] courtesy of Dr. Shaji Kumar).

The analysis was based on data from 454 newly diag­nosed myeloma patients who underwent initial ther­apy be­tween Jan­u­ary 2000 and De­cem­ber 2011 at the Mayo Clinic in Rochester, Minnesota. The median age at diag­nosis was 66 years.

The re­searchers found that over­all sur­vival times were shortest for patients who had very shallow re­sponses (3.3 years) or very deep re­sponses (5.1 years) after the first cycle of treat­ment, com­pared to the remaining patients (about 7.5 years).

Based on their results, the re­searchers be­lieve that patients with shallow re­sponses and well as those with very deep re­sponses during the first treat­ment cycle should be con­sidered as having high-risk dis­ease.

They rec­om­mend addi­tional stud­ies to de­ter­mine whether a change in treat­ment regi­men would benefit patients who do not respond to ther­apy quickly.

SL-401

Another poster summarized the results of a pre­clin­i­cal study of the inves­ti­ga­tional drug SL-401, which is being devel­oped by Stemline Thera­peutics (NASDAQ: STML) in cooperation with the Dana-Farber Cancer In­sti­tute in Boston (abstract).

SL-401 works by targeting the interleukin-3 re­cep­tor found on tumor-promoting plasma­cytoid dendritic cells. Plasma­cytoid dendritic cells are a form of immune cells.

The results showed that SL-401 in­hib­ited growth of myeloma cells by kill­ing the tumor-promoting plasma­cytoid dendritic cells that are abundant in the bone mar­row of myeloma patients.

Smoldering Multiple Myeloma

Another poster showed the results of a sys­tematic review that in­ves­ti­gated early versus late treat­ment of smol­der­ing mul­ti­ple myeloma (abstract).

The review was based on seven stud­ies that in­cluded 869 patients in total.  The treat­ments in­ves­ti­gated in the stud­ies were not all anti-myeloma ther­a­pies.  Instead, in almost half the stud­ies, the treat­ments in­ves­ti­gated were bis­phos­pho­nate ther­a­pies.

The results show that the risk of dis­ease pro­gres­sion was lower in patients re­ceiv­ing early ther­apy com­pared to patients who did not.

The results also show that the use of com­bi­na­tion ther­apy com­pared to single-agent ther­apy de­creased the risk of pro­gres­sion.

However, the re­searchers did not observe any dif­fer­ences in over­all sur­vival be­tween patients who re­ceived early treat­ment versus those who did not.

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Myeloma pre­sen­ta­tions from Day 4 will also be summarized in Beacon ASCO daily up­dates to be pub­lished in the upcoming days.  Addi­tional coverage of key re­search results from the meeting will con­tinue after the meeting is over with in­di­vid­ual, topic-specific news articles.  For all Beacon articles re­lated to this year’s ASCO meeting, see The Beacon’s full ASCO 2013 coverage.

Note: Electronic copies of conference pre­sen­ta­tions and posters made avail­able to the Beacon's readers are for personal use only. Fur­ther transmission or pub­li­ca­tion of the files is not permitted, although hyperlinks to the files are permitted with attribution to the author and to The Beacon (for example, "courtesy of Dr. Jane Doe and The Myeloma Beacon.")