Hairy Cell Leukemia: I Want a New Drug ...

I want a new drug... 

Okay, maybe not yet, but it looks like there are lots of new potential candidates for treating HCL that still have yet to be explored.  Two posts ago, I mentioned a new third-generation antibody that has the potential of being 5 to 100 times more powerful than Rituxan but hasn't been used to treat HCL yet.  I'm hoping some preliminary in-vitro studies will be conducted soon.

Today, I found another one -- a Btk (Bruton's tyrosine kinase) Inhibitor, PCI-32765, that is currently in Phase I clinical trials in patients with B cell malignancies (specifically Non-Hodgkin's Lymphoma).  Btk is an essential signalling factor needed for the development of  B-cells.  By inhibiting it, the Btk protein production is blocked and B-cells can't develop.  The inspiration for developing the drug was born from a disease, XLA, in which B-cells are absent from the peripheral blood because Btk is not produced due to a Btk gene defect. 

What's great about this drug is that it's a pill, taken orally, that inhibits Btk production and thus B-cell production.  Since HCL is a B-cell malignancy, I've asked the Hairy Cell Consortium if they are familiar with the drug and whether it may be a candidate for a Phase 1 trial to treat relapsed and refractory HCL patients.  I'll let you know if they respond. 

"This is a very selective compound for B-cells, and it could represent an important alternative to rituximab therapy for the treatment of B-cell NHL. Other obvious applications include autoimmune disorders such as rheumatoid arthritis and lupus, and Pharmacyclics also has strong preclinical efficacy with PCI-32765 in these disease models," said Dr. Mark Genovese, Professor of Medicine and Co-Chief of the Division of Immunology and Rheumatology at Stanford University Medical Center and member of Pharmacyclics' Scientific Advisory Board. [Taken from Pharmacyclics Press Release dated April 13, 2009]


Wouldn't it be great if we HCL'ers could knock out minimal residual disease (MRD) and then take a pill as maintenance therapy so that we'd never have to worry about it ever coming back?  Even better if it could act as the first-line therapy someday and eliminate the need for chemotherapy altogether (and side-effects like increased secondary cancer risk and impact to T-cell counts), or provide  a new treatment alternative for patients with HCL-V (the variant form of HCL that doesn't respond as well to Cladribine).

Prediction?...Pain!

After months of putting it off, I finally went to a new dentist last week.  He told me to see another endodontist to get a second opinion about the root canal and fistula that never resolved after the retreat 18 months ago.  The endodontist told me he's stymied, that it's not good to let the fistula linger because of possible bone damage, and to get the tooth (#14 molar) pulled.  Since the tooth extends into my nasal cavity, they may have to sew in some new bone to make it heal faster.  Once it heals, they'll install a post and a false tooth. 

Oh, and my dentist found a cavity under a cracked filling. 

The tooth extraction and filling cover the first week of December.  The following week, Dr.K is going to restage my progress in case they need to retreat with another round of Rituxan, which means another bone marrow biopsy (#6) on the 13th. 

My good friend Mr. T would like to have a few words:

Prediction? ... Pain!

The protocol has officially been ammended to allow two rounds of Rituxan for the delayed Rituxan cohort (the one that I'm in).  It's a simple one-line addition:  "Also may repeat for those with blood MRD six months after delayed Rituxan."  My flow was negative at 6 months post-Rituxan but has now been positive for 3 months, and will likely still be positive when I restage, so I'll probably receive another 8 rounds of Rituxan starting in January.   I'm very hopeful that this round may be even more effective than last year's since my counts are in good shape and my neutrophil level is much higher.

A high neutrophil count has been shown to correlate with improved antibody-dependent cell-mediated cytotoxicity (ADCC). In other words, the more neutrophils you have when you start Rituxan therapy, the more they can help kill the cells that are tagged with Rituxan. I'll be interested in seeing if I have another incidence of Rituxan-Related Late Onset Neutropenia (RRLON) at week 14 this time around.

I had a physical at my PCP on the 3rd.  Everything checked out fine.  My liver enzymes are holding steady at 22 for both the AST and ALT and my HDL is back up to 40 for the first time in 2 years!  I received 3 vaccinations:  tetanus, pneumonia, and flu.  I couldn't move my left arm for 4 days, but now I feel great.

Aside from that, I've been dabbling in some new favorite hobbies: studying organic chemistry, molecular cell biology, genetics and bioinformatics so that I can better understand some of the papers I've been reading on antibody research and lipid rafts.  I wish I could go back to school full time. 
(12/2/2010)  Tooth Extraction Follow-Up:  Had the tooth pulled.  Everything went fine, and the major bleeding stopped within minutes, although there was a very slow trickle afterward.  I'm hoping this means that there is continued improvement in my platelet count.  I was able to go without any gauze within 3 hours (probably sooner if I hadn't been so cautious).  There were several cysts (about 1 to 1.5 mm) that had formed at each root tip and had to be rigorously scraped off the bone after the roots were extracted.  The worst part was the high pitched squeal of the drill used to segment the root sections so they could be pulled individually.  1 day later, everything feels fine.  I just need to eat soft foods and avoid that side of my mouth for a few days.  In 2 to 3 months, I'll have an exam to verify the bone has grown back and then get a post installed.