Category Archives: ofatumumab

Oncology drug development questions for 2014: Combination therapies for B cell lymphoma

Part 1 – Ibrutinib and the development of combination therapies for B cell lymphoma

For physicians, patients, investors etc, major medical conferences are a way to check in on the progress of a company’s drugs in the context of the medical communities response to the data, i.e. the buzz. Negative buzz is generally pretty straightforward, reflecting poor results or unexpected toxicity in a clinical trial. Positive buzz should be (and often isn’t) more nuanced, as positive data, while great to see, need to be placed into the context of evolving clinical practice and the ever-present competition for patients. Results, positive or negative, need to be vetted for robustness: clinical trial stage, sample size, design; endpoint design; therapeutic window (the dose range between efficacy and toxicity); and duration of response.

Last year saw extraordinary advances in the treatment of B cell lymphoma, particularly the Non-Hodgkin Lymphomas (NHL) that include well known cancers like Chronic Lymphocytic Leukemia (CLL), Mantle Cell Lymphoma (MCL), indolent NHL (iNHL) and many others. This advances included small molecule therapeutics that target critical drivers of lymphoma cell proliferation and survival, novel antibodies (“naked”, enhanced, payload carrying), ex vivo modified patient T cells that attack lymphomas upon reinjection, and a variety of other modalities. It was interesting to see that the companies getting the most buzz varied during the year, with different companies “winning” different conferences. Be assured that in this context, winning reflects wins for the stock price! Winning in the medical marketplace is a whole different story.

With the medical marketplace in mind, a reasonable question for 2014 pops up when you step back and look at the breadth of the B cell lymphoma therapeutic landscape.

How will biopharmaceutical companies, physicians, and payers develop and use combinations of these therapies?

Lets think about the possible combinations. The most obvious are those that we are already seeing widely used, such as the combination of a small molecule inhibitor with a tumor-targeting antibody. One example is the combination of ibrutinib, a BTK inhibitor, and rituximab, an anti-CD20 monoclonal antibody. Ibrutinib was approved for treatment of relapsed/treatment refractory (rr) MCL in November 2013 under the brand name Imbruvica, and approval for rrCLL is expected soon (these indications were filed for approval together, in August 2013). Patients with relapsed/refractory small lymphocytic lymphoma (SLL) were included in the CLL arm of the clinical trial.

CLL is a good example of the power of combination therapy. Rituximab monotherapy in rrCLL/SLL produced overall response rates (ORR) in the range of 55% and a complete response rate (CR) of somewhere under 10%, depending on the trial. Note here that ORR and CR refer to assessments of tumor burden at a specific and predetermined time after treatment is initiated. A CR does not indicate a cure but rather is a measure of the degree of efficacy. The ORR and CR measurements are most meaningful when presented in the context of duration of response (DOR) or in the context of progression-free survival (PFS) or overall survival (OS).

Monotherapy of rrCLL/SLL with ibrutinib produced ORRs ranging from 70-80%, with CRs ranging from 0 – 10%. Duration of response was good, and there was a measurable impact on PFS. There are different classes of rrCLL patients, based on cytogenetic status. High risk CLL patients commonly carry a deletion on chromosome 17 (del17p) and/or other abnormalities. Such mutations predict poor prognosis for these patients. Last April, the FDA granted Ibrutinib Breakthrough Therapy Designation for high-risk rrCLL/SLL del17p patients based on achievement of a 50% ORR in these patients when given ibrutinib monotherapy.

Now to the combination of ibrutinib and rituximab (and a chemo agent, bendamustine). As discussed in earlier coverage of the American Society of Hematology Annual Meeting (ASH), linked here, treatment of high-risk CLL patients with the combination therapy produced an ORR of 95%, with 78% maintaining response through 18 months. While only 10% of the responses were designated CR, the long duration of the partial responses (PR) was a dramatic result.

The cost of Rituxan treatment for B cell lymphoma is generally quoted at ~10K/month but billed to insurance at about 5K monthly, so we are somewhere between 60-120K per year per patient in the US. Imbruvica will cost 130K per year per patient in the US. Note here that neither therapy, given alone, is considered curative. We don’t know yet what the durable remission rate will be for the combination therapy, where we define durable remission as no detectable disease (in the blood, lymph nodes, bone marrow) without maintenance therapy. Curative treatment means no disease in a patient who no longer requires drugs.

So it’s fair to say that these combination therapies will be very expensive and may need to be used for a long time. Given the current climate of cost control, especially outside of the US, what are companies doing to anticipate eventual pushback on premium pricing?

Just a quick reminder that Imbruvica (ibrutinib) is a Pharmacyclics/Johnson&Johnson (J&J) product and the Rituxan is a Roche product and further, that Roche has a next generation anti-CD20 antibody, obinutuzumab, recently approved for the treatment of CLL (including as first line treatment), under the brand name Gazyva. This antibody given in combination with a cheap chemotherapy agent, chlorambucil, produced an ORR = 78% and a CR of 28% in the phase 3 trial. This antibody was significantly better than Rituxan (rituximab) plus chlorambucil in the same clinical trial (ORR = 65%, CR = 7%). The trial was done in rrCLL patients including high-risk patients defined as del17p.

Another anti-CD20 antibody, ofatumumab from GSK, has been approved for second-line use in rrCLL. This drug, priced at 120K yearly, ran into reimbursement pressure in Europe and the UK as not showing sufficient benefit to justify the price. This is a hint of price pressures to come.

This is where I think things get really interesting. I spent some quality time on, trying to understand how companies competing in the B cell lymphoma space are looking ahead, the assumption being that one can do this by looking at the trials planned or underway for the top tier drugs. Many of the oral drugs in advanced development for B cell lymphomas are reviewed here.

Nearly all advanced oral drugs for B cell lymphoma have trials underway or planned with an anti-CD20 antibody. Most of these trials are done with rituximab, probably just reflecting the wide availability of this antibody. Perhaps some companies are sticking with rituximab in the belief that generic biosimilar forms of this antibody will become available in Europe (where it is now off-patent) and in the US (where patent protection expires in 2018), which may make combination therapy more widely available. The rituximab trials are not done in collaboration with Roche, with one notable exception which we will get to later.

There are 11 clinical trials listed as active that include ibrutinib with rituximab either alone or with various other agents. Some of these trials have already read out results:

NCT01980654210/24/2013rituximabuntreated FL
NCT0152051921/25/2012rituximabhigh risk CLL, SCL
NCT0161109035/15/2012rituximab/bendamustinerrCLL, rrSCL
NCT0177684031/24/2013rituximab/bendamustineuntreated MCL
NCT01479842111/1/2011rituximab/bendamustinerr DLBCL,MCL,iNHL
NCT0188687236/24/2013noneuntreated CLL
v rituximab/bendamustine
NCT01974440310/28/2013R-CHOPrr iNHL
v rituximab/bendamustine
NCT0188685916/24/2013lenalidomiderrCLL, rrSCL
NCT0182956814/9/2013lenalidomide & rituximabrrFL
NCT0195549919/27/2013lenalidomide & rituximabrr iNHL

Note that FL is follicular lymphoma and DLBCL is diffuse large B cell lymphoma. DLBCL-ABC is a subtype. These are all types of B cell lymphomas. R-CHOP is rituximab plus a standard mixture of chemotherapeutic agents, and I may or may not have defined this correctly, suffice to say if it says CHOP then there is a potent mix of chemo being given; “v” means versus, that is, it is a comparator arm.

There are another seven or eight single agent ibrutinib trials also, but I did not include those here, so what we see all together is a full court press of clinical trials designed to show benefit of ibrutinib in multiple different B cell lymphomas, as first line or second line therapy. These trials will produce a tidal wave of data that, if positive, will by their sheer volume place ibrutinib at the top of the heap of B cell lymphoma oral agents. So, yes, I’m betting on Pharmacyclics (stock symbol PCYC) and J&J to win the marketplace, at least for the near term.

Ibrutinib development does not stop there. There are three trials with lenalidomide, also known as Revlimid, approved as second line therapy for multiple myeloma (MM). A monotherapy trial of lenalidomide in CLL was halted last year due to an increase in deaths seen in the active arm. Even at a reduced dose (I’m guessing here) the use of this agent plus ibrutinib plus rituximab seems risky. Also, the drug is owned by Celgene. So why conduct trials with lenalidomide at all? The answer to that question will be found in the list of clinical trials for CC-292, Celgene’s BTK inhibitor under development for B cell lymphoma.

But just to finish with ibrutinib. Here are the rest of the active clinical trials I could find:

NCT020131281,212/11/2013ublituximabCLL, MCL
NCT0157870734/11/2012v ofatumumabrrCLL
NCT0184172321/24/2013noner Hairy Cell leukemia

Ublituximab is a new anti-CD20 antibidy from TG Therapeutics and the clinical trial is being run by that company, not by J&J/PCYC. In contrast the ofatumumab trials, which are “active but not recruiting” are sponsored by Pharmacyclics.

Finally, just some tidbits. Ibrutinib presentations recently have included studies in some interesting new indications, particularly MM. There are two MM trials shown here, the second one being run in collaboration with Onyx Pharmaceuticals, whose proteosome inhibitor carfilzomib, has been approved for treatment of rrMM under the name Kyprolis.

I suspect we will see many more such collaborative efforts as the field matures.

Next up we will look at the efforts of two of the compounds seeking to compete with ibrutinib, Gilead’s idelalisib and Celgene’s CC-292.

Stay tuned.

SnapShots from the 2013 American Society of Hematology Abstracts – Part 5

Part 5. Key Biologics in Clinical Trials.
November 20, 2013
The American Society of Hematology Meeting will take place in New Orleans,
December 7 – 10, 2013. The abstracts are available at
In parts 1-4 we meandered through the small molecule, mainly oral drugs,
highlighting a few key pathways and focusing mainly on CLL.
Biologic drugs are a different and equally important class of therapeutics for lymphoma
treatment, and really it is Rituxan, the antibody that depletes cells expressing CD20, that
ushered in the new era of non-chemotherapy-based drugs. Some of the small molecule
trials discussed earlier were done in combination with anti-CD20 antibodies with or
without added chemotherapy. This therapeutic trend toward combination therapy will
dominate the lymphoma landscape, with chemo, targeted small molecules, and antibodies available to mix and match, just so long as they are not too toxic when combined, provide additive efficacy, and we can afford to pay for them. One might also overlay immuno-
therapy approaches – checkpoint modifiers, CAR-T modified cells, even cancer vaccines -
and of course there is also the whole bone marrow or stem cell transplantation field.
There are notable new biologics being developed for the treatment of lymphoma, and a
few of these have new data available in the ASH 2013 abstracts.
The real question is whether anything will be able to compete with the novel anti-CD20
mAb obinutuzumab.
Obinutuzumab (GA101) is aglycoengineered antibody having 10-fold greater affinity 
for FcgammaR3A. This is receptor on cytotoxic NK cells that binds to the Fc domain 
of the antibody. The binding of the Fc domain to the FcR (receptor) triggers killing of 
the target (CD20+) cell by the interacting NK cell. Obinutuzumab was approved under 
the brand name Gazyva on November 1st for use in combination with chlorambucil to 
treat patients with previously untreated CLL. This was this first drug approved under 
the FDA’s new breakthrough therapy designation and wasbased on a Phase 3 study of 
previously untreated CLL patients (n = 365) comparing Obinutuzumab plus chlorambucil 
to chlorambucil alone. The PFS for the combination therapy was 23 months compared 
with 11.1 months with chlorambucil treatment. Additional data from the Phase 3 trials, 
comparing obinutuzumab pluschlorambucil (OB-c) to rituximab (Rituxan) plus 
chlorambucil (R-c), are to be presented during the plenary session at ASH (Abstract #6). 
Those data are summarized as follows:
26.7 months
15.2 months
*: MRD is minimal residual disease, meaning that bone marrow and organs are negative 
for tumor cells.
AEs were higher in the obinutuzumab plus chlorambucil arm, although it appears that 
this was due to increased severe infusion-related reactions, which can be controlled.
Another study in previously untreated CLL patients will be presented at ASH (Abstract
#523). In this trial, obinutuzumab (OB) was combined with fludarabine/cyclophosphamide 
(FC) or bendamustine (B). There are 41 patients enrolled and the median reported followup 
time is nearly 12 months. 9 patients (22%) had to discontinue treatment due to AEs, mainly cytopenias. The investigators will report and update response data, summarized here (note 
that CRi, defined as complete response with incomplete bone marrow resolution, is included 
in this table with the %PR):
not reached
not reached
No responding patients progressed and PFS was not reached. While the data look very good
for efficacy, the fact that a high percentage of patients had to discontinue due to AEs is
Two other studies will be presented at ASH. One is on the treatment of CD20+ Diffuse
Large B Cell Lymphoma (DLBCL) patients in a Phase 2 clinical trial (Abstract #1820).
DLBCL is an aggressive lymphoma, currently treated with combination chemotherapy
(CHOP: cyclophosphamide, doxorubicin, vincristine, prednisone) or with rituximab plus combination chemotherapy (R-CHOP). In this trial, 80 previously untreated DLBCL
patients were treated with obinutuzumab plus CHOP. The ORR = 83%, consisting of
CR = 55% and PR = 28%. Of the 80 patients total, 11 patients discontinued treatment,
5 of these due to AEs (6.25%), but in general AEs were manageable. Nine patients had
PD, three died. These preliminary results are very encouraging, updated results including
analyses responses in DLBCL subsets (ABC v GC) and with reference to molecular
classification will be presented at the meeting. An earlier study (Abstract #1814) will
present data on the use of obinutuzumab as maintenance therapy after induction therapy
with chemo (either OB-CHOP or OB-FC). Patients had rrFL (follicular lymphoma). The
induction data was published by Radford et al. in Blood, 2013, volume 122, page 1137ff. 
CR rate was monitored at the start and end of maintenance therapy, with the maintenance 
period being a median of 35 months across the two cohorts. CR as a best overall response increased on maintenance with obinutuzumab in the OB-CHOP cohort (52%, PFS not 
reached) and in the OB-FC cohort (82%, median PFS = 46 months). Finally, a combination 
trial of obinutuzumab and ABT-199 is currently in phase Ib (NCT01685892).
These studies show benefit of obinutuzumab therapy in different lymphoma populations
using a variety of treatment paradigms, and point to the importance of this biologic
therapy in B cell lymphoma treatment.
There are a large number of new biologics competing for attention; just a few are discussed
Another anti-CD20 antibody with breakthrough status is ofatumumab (Arezza). Approved in
2009 for use in rrCLL patients, this antibody is moving toward use earlier (i.e. in newly
diagnosed CLL) and in other patient subsets.
In May of this year, positive phase 3 data for ofatumumab were announced by GSK. Patients
with previously untreated CLL (n = 447) received ofatumumab plus chlorambucil (OF-C) or chlorambucil (C) alone. The study found that patients in the ofatumumab cohort experienced
a longer median PFS. That study will be updated at ASH (Abstract #528). Top line data is
22 months
13 months
Other studies on ofatumumab being presented at ASH include a phase 2 trial in combination
with dexamethasone, to treat high risk rrCLL patients (Abstract #2877). This study presents
a CR = 16% and PFS = 10 months, although the infection risk was quite high. Another
phase 2 study is testing the efficacy of ofatumumab in combination with the AKT inhibitor afuresertib (Abstract # 4175) in the treatment of high-risk rrCLL patients. In this small
study (n = 19) AEs were manageable (neutropenia, GI complications) but responses were
low: ORR = 42%, CR = 0, PR = 42%; 58% of patients had SD, and 26% of patients
progressed. Several other trials will also be updated (Abstracts #1645 and 4177).
An example of the high bar set by obinutuzumab therapy can be seen in several trials of
other biologics. Pfizer has developed an antibody/drug conjugate (ADC) called inotuzumab ozogamicin (InO). This is a humanized anti-CD22 antibody conjugated with calicheamicin, 
a potent cytotoxic. CD22 is expressed on most forms of NHL. The trial (Abstract #1821) 
is a phase 1 dose escalation trial designed to identify the MTD in combination with 
rituximab plus chemo (gemcitabine, dexamethasone, and cisplatin). AEs, mostly
cytopenias, causing dose reductions and dose delays established the MTD. Patients had 
rrNHL, with 21 DLBCL, 14 FL, 12 MCL, 4 SLL, 1 MZL, and 3 other indolent B-NHL.
At the MTD dose the ORR = 45% and the CR = 22%. Of the 55 patients enrolled, 12
(22%) discontinued due to AEs and 12 (22%) discontinued due to PD. These numbers
are a little worrisome although this is a difficult patient population to treat. It will be
important to see PFS and OS numbers as clinical development of this therapy continues.
An intriguing target for antibody development is CD37. CD37 is tetraspan protein expressed
on a variety of hematopoietic cells, and can transmit a cell death signal through its SHP-1
domain. Trubion engineered a modified antibody called TRU-016, now being developed by Emergent (see the 14 November issue of Blood – volume 122, p 3397 – for a brief description 
of this and other anti-CD37 targeting agents). Phase 2 data on TRU-016, now called 
otlertuzumab, will be presented at ASH. Otlertuzumab induces cell death directly (ie. by 
signaling cell death) and also through Fc-mediated cytotoxicity. The phase 2 trial recruited 
65 rrCLL patients who had failed between 1 and 3 prior therapies. The Abstract (#2860) 
presents data on 44 evaluable patients treated with otlertuzumab (OTL) or with otlertuzumab
plus bendamustine (OTL-b). The data are as follows:
% progression
The % progression data refers to the responding patients only. AEs were in line with the chemotherapy treatment. A second study (Abstract #4165) provides preliminary data on
patients treated with otlertuzumab plus the anti-CD20 antibody rituximab (Rituxan). This
dual antibody therapy was given to previously untreated CLL patients. Preliminary data
suggest an ORR = 88%, and modest AEs. This trial will be updated at the meeting. These
early studies suggest that targeting CD37 is an attractive approach for CLL therapy.
BITE antibodies are bi-specific antibodies originally developed by Micromet. They have
received a lot of press following the 1.2 billion dollar acquisition of Micromet by Amgen. Blinatumomab binds to CD3 on T cells and CD19 on lymphoma cells, helping to direct the
T cells to recognize and destroy the tumor cell (BITE stands for BI-specific T cell Engager). Abstract #1811 has some very early data on blinatumomab treatment of rrDLBCL patients.
Lets be clear upfront that this is a tough patient group to treat. At the time of abstract
submission, 11 patients were enrolled with initial ORR = 57%. It will be very interesting
to hear updated results from this trial at ASH, including both efficacy and AEs, which at
first glance seem tolerable if unpleasant (including CNS toxicity).
MEDI-551 is an afucosyl-anti-CD19 antibody with augmented cytotoxic activity (due to the
lack of fucosylation of the antibody). An 83 patient Phase 1 trial (Abstract #1810) enrolled heavily pretreated rr CLL, DLBCL, FL, or MM (multiple myeloma). All of these B cell lymphoma types are CD19 positive. The ORR = 25%, with CR = 10.8% and PR = 14.5%.
50.1% of patients were characterized as SD. PFS was calculated to be 9 months. At first
glance the single agent responses are substandard; MedImmune is continuing development
of MEDI-551 in combination with chemotherapy.
A CD19 ADC has advanced to phase 2, in a combination trial with rituximab (Rituxan).
SAR3419 is a humanized anti-CD19 antibody conjugated to maytansin DM4, a cytotoxic
agent. It is under development by Sanofi and was licensed from ImmunoGen. This ADC
was given along with rituximab (Rituxan) to rrDLBLC patients (refractory to first line
therapy or relapsed after a prior therapy; Abstract #4395). ORR was low at 31% and 36%
of responders progressed by the end of the study. Sanofi plans to move this agent into
patient populations that may be more responsive.
So, here we have seen two anti-CD19 antibody therapeutics with rather poor efficacy
I want to end with an old dog/new trick story concerning alemtuzumab. First studied many
years ago in the context of transplant rejection therapy, this anti-CD52 antibody lives on as
a treatment for hematological malignancies (CD52 is widely expressed) and, under the
brand name Lemtrada, as a therapy for multiple sclerosis. The long strange trip of this
nasty antibody (the side effect profile is not good) is the subject for another day. Of interest
at ASH however is a nice study looking at the utility of alemtuzumab for very high risk
treatment naive CLL patients (Abstract #2861). High risk is defined here genetically – these
are patients with genetic deletions or mutations known to be associated with poor prognosis. Without diving into the details, the investigators have shown that TP53 mutations had an
adverse prognostic impact and shorter PFS and this was overcome by alemtuzumab treatment. This then presents itself as a potential therapeutic for patients known to have this poor risk
If time allows I want to discuss the CAR-T technology, perhaps in the next section.